Buy RAM chip heatsinks on eBay and use thermal epoxy to glue them right to the IC
I'd be less concerned about the U800 chip and more concerned about the 4 tantalum
surface mount capacitors on the A5 board. They are known to leak with corrosive electrolyte
over time and can absolutely destroy the A5 board.
Maybe you think that Tektronix EE's who design it are stupid?
They are not.
It works just perfect and thermal design is ok. There is NO any problem. Exept if someone take case off and use it without case. Also if FAN go bad it can go to thermal owerload.
Maybe you think that Tektronix EE's who design it are stupid?
They are not.
It works just perfect and thermal design is ok. There is NO any problem. Exept if someone take case off and use it without case. Also if FAN go bad it can go to thermal owerload.
I have study and inspect these oscilloscopes years (also I have no 3 pcs of these units in my lab for service and calibrate.
You can read Tektronix original full service and repair manual before you open oscilloscope if you design also power up it without case. It need use service enough airflow fan if need more time keep it running without case!
In the world you can find hundreds of defected Tektronix oscilloscopes just as burned hybrids and IC:s just becouse user do not care or "self learned service man" do not know how to handle these as professionals do who are specialised to make repair work with these nice scopes.
60 celsius is NOT hot. 90 celsius is not hot. 100 celsius is not hot.
When case is closed and airflow work normally it keep it fully inside accepted temperature area.
If not believe you can put thermal sensor over chip and close case. Temp is more low than in free air temp.
same for these some maybe more sensitive hybrids.
And also concern about this (mostly DALLAS) NVRAM. (this is designed lifetime!) Before they use EEROM and also RAM+Separate extremely good Lithium battery. (but reducing lifetime and costs...it is...what it is.)
I'd be less concerned about the U800 chip and more concerned about the 4 tantalum
surface mount capacitors on the A5 board. They are known to leak with corrosive electrolyte
over time and can absolutely destroy the A5 board.
There's another thread on the forum about the A5 board, or you can look at this repair
guide someone put together:
http://www.condoraudio.com/wp-content/uploads/Projects/Tektronix-2465B-Oscilloscope-Restoration-Repair.pdf (http://www.condoraudio.com/wp-content/uploads/Projects/Tektronix-2465B-Oscilloscope-Restoration-Repair.pdf)
Scott
This week I had the case off my 2465CTS. In some aspects it is quite similar to the B version in this thread, but for example the digital controller PCB (wow... an 68B08, nice, I grew up with 6800 and 6809 ;-) is through-hole and not SMD.
It was suffering from a rattling fan, which had an interesting cause: it had been stored (at work) on its side on some shelf. And apparantly some fat-fisted colleague of mine had dumped it on its side hard enough to push the handle lever into the case. This caused to whole case to dent and slightly deform. >:( The aluminium of the case is really quite soft. End result was that the fan (mine has a "rodent wheel" style fan) just touched the plastic back of the scope. Which rattled. Sigh..
Interesting (...) side effect was that the outer shell would not slide off the frame. I had to "crowbar" the side of the case somewhat to get it off. Once it was off, I could hammer (yes.. I had to use a hammer to fix a scope..) the dent out, which made the case slide back easily onto the frame.
Oh.. And I had to fit a new 10Mc Xtal on the digital controller PCB. That got stuck behind the dented case and broke off. ::)
Ah well, it is back to its glorious self again. I got it years ago (for free, can't complain there!)
Wilko
And yes MTTF goes down with temperature, so if the chip is seriously hot, I would *consider* adding a heatsink, or a small extra fan, though with the caveat of thinking how the whole airflow though the system is arranged.
Good points on the fan replacement though.
If not believe you can put thermal sensor over chip and close case. Temp is more low than in free air temp.
same for these some maybe more sensitive hybrids.
Surface temp will never be lower than ambient temp if using air cooling at "a non evaporating surface", its the basic law of thermodynamic, not sure where did you learn yours.
It looks that scope need service calibration.That is what I'm afraid of, cause I don't have enough supporting tools to do that, while sending it to certified calibrator is not an option since its way too expensive, the cost of certification might be more than a new 200Mhz china made digital scope. :'(
If do adjustments it need follow _exactly_ Tektronix service manual. There are not words without meaning (even if it feels stupid..).
How is measurement accuracy?
(btw. now you have adjusted readings location without service calibration procedures - remember, they maybe now adjusted wrong and after (or better tell inside) service cal procedure you may need adjust also this agen).Nope, checked with service manual, the adjustment I've made at R2918 to fix the readout vertical position is not part of the calibration procedure that will be stored as calibration data, check again your service manual.
Although the U800 post is some days ago here my solution, which is similar to Yours but I used a bigger Heatsink with a hole for the screw to avoid electrical contact. Bevor mounting the heat sink with normal super glue I isolated the screw with a plastic tube.
Also I have a question if You would be so kind to tell me if I'm right.
When I got my Tek2465A I wondered about the missing illumination. So I decided to open the front panel where I expected the bulbs - but I found nothing (see last picture). Shouldn't there be the illumination lights?
Yes I got a service manual, but the part with the illumination is not illustrated so good. So I thought it is better to ask some knowing guys about it :)
Am I right when I suppose that the red marked connector is the supply connector for the illumination?
(btw. now you have adjusted readings location without service calibration procedures - remember, they maybe now adjusted wrong and after (or better tell inside) service cal procedure you may need adjust also this agen).Nope, checked with service manual, the adjustment I've made at R2918 to fix the readout vertical position is not part of the calibration procedure that will be stored as calibration data, check again your service manual.
Thanks for the reply, that confirms my speculation about the missing illu.
Btw, if someone has problems with the eproms on the digital board loosing their "mind" - I read them out and can share the files if needed. I guess they are different for the models 2465/2465A/2465B (my model is 2465A).
Oh, I forgot this other site for firmware (and manuals):
http://www.ko4bb.com/manuals/index.php?dir=04 (http://www.ko4bb.com/manuals/index.php?dir=04))_ROM_Images_and_Drivers
Lots of good people trying to keep old test equipment alive by
archiving firmware images against eventual bitrot.
Scott
<snip>
P.S. Also I need to do something with the cooling off U800, I think there is a factory fitting error, IMHO there should be no shims between the IC a PCB, U800 should adhere directly to the PCB.
After I get done with calibration, I will add additional heatsink.
<snip>
@Jason (hepcat)
Thanks for the info, sounds very interesting. :-+
Do you have any photo shoots on how mod was done at the U800 ? Really appreciate it if you could share it here, I'm very interested and pretty sure other U800 owners too. ;)
I'm using the 2445B image, because the measuring errors are satisfactory for me without calibration. Your images also operate normally, but the calibration data does not match to my hardware - error of measurement is 15...20% in my scope.
I don't know the part no of this BBSRAM, originated from an old RICOH photocopying machine, was located on main control board PWB no. A1535112. The EPSON chip is a 256K-BIT SRAM with Extremely Low Standby Current. It's like a Dallas DS1225 without cover and with larger battery :). Address lines A13, A14 are grounded and disconected from scopes board. Did not work properly as they were connected.
I am curious how it goes with FM28V020. It's hard to get !
Looks like all analog Tek 24xxB scope's SRAM image are compatible each other, never expected that, great finding.
I'd be reasonably sure that 1996 fan was a replacement. They wouldn't be using Dallas chips with a 1989 date code in a 1996 scope. A lot of old Sun workstations use similar Dallas chips to hold the MAC address and configuration data and it is fairly common for those to have died with an FF:FF:FF:FF:FF:FF MAC address.
replacing the dallas module (not really looking forward to unsoldering it, to be honest.)I'm afraid you just can not escape from that. >:D
I just bought another 10-20 years of cal data ;) and the next guy does not have to unsolder that crazy chip.
I was able to calibrate my 2465BDM starting from a downloaded NVRAM from the KO4BB web site, programming a new NVRAM and calibrate most of the settings with the equipment I have. I'm not a calibration site by any means but willing to help if you're in my neck of the woods (Tucson, AZ)
anyway, it seems done now. I'd like to get it professionally calibrated but at least its rejuvinated.
I bought this scope on EBay from - rcatechalert_guy - as having been refurbished as follows: "The LV power supply filters (Capacitors) replaced with units with better specifications; The A5 control board SMD capacitors were replaced and potted. Do you see evidence that this was not done?
The areas that look like scorch marks are actually a resin of some sort. I'm assuming that this was done to protect against any future capacitor leakage damage, but I can't see through the stuff.
Hmmm. I've thought about this all day, and I agree that the seller really should be expected to replace this board with a functioning and professionally refurbished substitute. After struggling with this for awhile, and reading your identical suggestion - I did write to him again and ask that he fulfill this compromise. I asked for a professionally refurbished substitute board, as that is what I paid for in the first place (as I have no experience replacing surface mount components), and as I believe he should be given the chance to make good on the work.
Another question: Could changing out old power supply capacitors change scope characteristics such that a scope calibrated within the past few years could then fail to function because of retained NVSRAM calibration factors that were recorded at last calibration, when the older components were in place?
Thanks and credit to Kibi for allowing me to share this photos here. :-+
Quoting his tips & photos on detaching the A1 board :
1. Must unsolder the wires that go to the X and Y plates.
[...]
Just a minor note - You don't have to unsolder these wires. They lead to single pin connectors on the CRT neck. You can pull them off the CRT through the slot in the shield (carefully!).
The individual wires are not joined together. Those "pins" sticking out of the shield are actually connectors. You can pull on them, gently, to detach them.
I've attached a picture of what it looks like without the shield. (It's a different type of wire, but I'm just trying to illustrate what I mean). This is a 2465 CRT (#154-0850-01) and you can see the three pins from your picture. There are 4 pins on the other side where it attaches to the A1 board.
The CRT pins are thin and delicate. Avoid bending them as much as possible since you don't want to stress where it goes into the the metal-to-glass seal.
I've also attached a picture of the whole gun assembly. I think it's an impressive piece of glass work. Those little dots taped to the outside are magnets to tweak the beam position.
Actually, if you need to take it apart is a good idea to disconnect and reconnect those pins as they tend to rust a little. So many problems can be fixed that way :)I'll second that. When I got my 2465 the traces were intermittently jumping vertically. I traced it to one of the deflection plate connectors.
I picked up a 2465B today, which as it is in full working order isn't something I'm going to take apart, but have enjoyed seeing what's in there.
I picked up a 2465B today, which as it is in full working order isn't something I'm going to take apart, but have enjoyed seeing what's in there.
If its still untouched from Tek factory, as least you need to do the A5 digital board to refresh the pesky Dallas bbsram that is holding the scope cal. , and definitely its already passed it's specified battery life.
Btw, just curious, you're well known here that have access or probably own many high end T&M gears and also selling them, which some beyond the reach of common hobbyists level, why still buy this "old clunker" ? :o Sentimental value ? Anyway, welcome to the club. >:D
If its still untouched from Tek factory, as least you need to do the A5 digital board to refresh the pesky Dallas bbsram that is holding the scope cal. , and definitely its already passed it's specified battery life.Does this effect ALL 2465 models?
The SMD caps on the A5 in the 2465B board are also notorious - probably should be replaced even if they look OK (see earlier in this thread).+1, the well known problems for this Tektronix series which are the SRAM battery that is running out of juice, and the SMD electrolytic caps at the A5 board that leak like hell, this thread has a good example -> HERE (https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg406487/#msg406487), or HERE (The damaged vs the good one) (https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg406409/#msg406409) :o
Does this effect ALL 2465 models?Dom, not sure about your 2465CTS, maybe you can share the photo of your A5 digital board about the caps and maybe its using the same Dallas DS1225Y too, not very sure my self.
Is this process documented/detailed anywhere?
Dom
Does this effect ALL 2465 models?
The SMD caps on the A5 in the 2465B board are also notorious - probably should be replaced even if they look OK (see earlier in this thread).+1, the well known problems for this Tektronix series which are the SRAM battery that is running out of juice, and the SMD electrolytic caps at the A5 board that leak like hell, this thread has a good example -> HERE (https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg406487/#msg406487), or HERE (The damaged vs the good one) (https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg406409/#msg406409) :oDoes this effect ALL 2465 models?Dom, not sure about your 2465CTS, maybe you can share the photo of your A5 digital board about the caps and maybe its using the same Dallas DS1225Y too, not very sure my self.
Is this process documented/detailed anywhere?
Dom
On the Dallas, its a "Battery" Backed Static Ram (BBSRAM), and just read the datasheet yourself, it's specification on the battery life is maxed out only for 10 years. And if your 2465CTS also using it, its very likely already aged more than 10 years.
I'll drop a photo of the board here after lunch (about 3 hours from now).Yep, the long rectangle shaped board at the right side of the scope (front view), and if you see it closely, the board has almost all logic chips populated in it.
The A5 logic and control board is the one the outside right of the scope looking from the front right?
Dom
I bought it because it was the right price. I may need a fast scope soon, just bidding on some design work that may need a genuinely fast scope and the next fastest analogue scope I have is a 150MHz 2445. I do prefer analog scopes for looking at analog signals.
I'll drop a photo of the board here after lunch (about 3 hours from now).Yep, the long rectangle shaped board at the right side of the scope (front view), and if you see it closely, the board has almost all logic chips populated in it.
The A5 logic and control board is the one the outside right of the scope looking from the front right?
Dom
Sorry didn't mange it at lunch... mine does not look like that. All through hole, no SMD
All the boards look like have zero corrosion on them and almost pristine condition (bit of dust).
So looks like might not have anything more too do. Those caps 0.068uF.... I have 0.1uF close enough or do I need to stick wit the value?
Dom
I bought it because it was the right price. I may need a fast scope soon, just bidding on some design work that may need a genuinely fast scope and the next fastest analogue scope I have is a 150MHz 2445. I do prefer analog scopes for looking at analog signals.
Hey KJDS, I just visited your ebay shop and I can see you're also selling a 500 Mhz DSO. :o
Understand its an old DSO, its just I'm very curious why your prefer using a 400 Mhz old analog scope than the one you already have in hand ?
Please, if its not too troublesome for you, share on the real world examples or any reasons even its subjective that at your design work, this old clunker is better than that DSO, maybe create another new thread for that ?
I have created photos and break down notes from my 2465CTS... slightly different model to what I have seen here and lot more packed inside.
http://m1kta-qrp.blogspot.co.uk/2014/04/oscilloscope-tektronix-2465cts.html (http://m1kta-qrp.blogspot.co.uk/2014/04/oscilloscope-tektronix-2465cts.html)
Btw, if I'm not mistaken these made in 90s or with serial no. > 50000 don't use the crap high voltage cap anymore like Dom's, but just suggesting to check it out.
The left section is the high voltage mains area, in there there are two red boxed caps pointed by the blue arrows. This type should not be a problem.
(https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/?action=dlattach;attach=89407;image)
While bad example are like at older version which uses these well known transparent caps that will burst once aged. :-\
(https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/?action=dlattach;attach=89405;image)
Dom, permission to "steal" your photo if you don't mind. :P
.... if I'm not mistaken these made in 90s or with serial no. > 50000 don't use the crap high voltage cap anymore like Dom's, but just suggesting to check it out.BTW everyone do not assume just because the serial number (front panel to the right under the 2nd channel input) is >50000 these capacitors are not used.... my serial is B050949, visually check them, mine had a HV black cover over the area so you have to take that off first.
Anyone got the CTS manual anywhere? I can use it as a regular scope (2+2 channel) but not worked out the CTS bit yet.... or found a PC to scope interface I can clone.Look around the net for the regular 2465 option 09 (counter timer/word recognizer) and option 10 (GPIB) manuals. The CTS was just a specially priced bundle of those options plus some additional probes. After a quick look I'm not seeing a free PDF of them, but you can search some more.
Dom
Here's the link to the "24X5A/2467 Options Service Manual". It contains service info for the following options.These are for the "A" version. From the old catalog info I have, the CTS version is based on the plain 2465 (no A or B).
[...]
I just need to find two small replacement knobs for the intensity and focus controls.
Thanks for everyone's great info about replacing the leaking caps and battery-backed RAM in the Tek scopes. I just picked up a nice 2467B and it works great but does have a small amount of black sludge around the capacitors on the A5 board. I'm going to embark on the project to replace those caps and put a fresh BBSRAM on the board, but I'm curious what the best way to clean the sludge off the board is. Should I try to clean before desoldering the caps so I don't "cook" the stuff onto the board, should I just get the caps out of the way then clean, etc. Is Isopropyl alcohol the right cleaning agent to use?
.... if I'm not mistaken these made in 90s or with serial no. > 50000 don't use the crap high voltage cap anymore like Dom's, but just suggesting to check it out.BTW everyone do not assume just because the serial number (front panel to the right under the 2nd channel input) is >50000 these capacitors are not used....
That thing looks like a big piece of charcoal! Can anybody tell me what that thing is and what could have been going on here?It's the coupling for the final anode connector - so that you don't have to disconnect the cup if changing a CRT.
the power supply board pair comes out as a pair. loosen the rear screws since its physically tight and very hard to remove the way tek designed it. I struggled a lot to get my board pair out. its not meant to be taken out, so you -have- to loosen a few chassis screws to -create- clearance to remove the boards.
Does anyone have the part numbers for those 2 HV caps handy, before I dig into the service manual? Thanks a lot for all the help given in this thread so far!
A quick question for all the 2465 users here. One of the things i notice is that the brightness of the traces goes up if i switch on more channels. ........
I'm wondering if this is a bug or a feature. .............
I've read the temperature stories about the U800 chip. But i was also told it is not related to temperature, but because of outsourcing the manufacturing from tek to a third party. The original tek chips don't break. If that is true, i'm safe as it is a very early 2465 (Guernsey). It is also full of factory installed bodges (as in reworks).
I've read the temperature stories about the U800 chip. But i was also told it is not related to temperature, but because of outsourcing the manufacturing from tek to a third party. The original tek chips don't break. If that is true, i'm safe as it is a very early 2465 (Guernsey). It is also full of factory installed bodges (as in reworks).
Well, my U800 chip was almost too hot to touch by fingers at the black ic body even there was a big fan blowing strong wind on it.
Yes, it was outsourced to Maxim IC after Tek decided not to produce it anymore, as far as I know, there are two versions of this U800 chip (TEK part no 155 0241 02) , photo of both attached below.
Well, not really outsource. Tektronix had its own internal IC fab - called the Integrated Circuits Operation (ICO). Tek sold ICO to Maxim in 1994. It is still co-located on the Tektronix campus in Beaverton. So, the name changed, but the fab remained the same.Straight from the horse's mouth, thanks Alan for clarifying this. :-+
At the same time, Tektronix sold half-interest in their hybrids design and manufacturing group to Maxim, which formed the group known as MaxTek. Several years ago, Tektronix bought out Maxim's interest in MaxTek, returning this group to be wholly owned by Tektronix.
Seems that I should start with A5 board (it is all SMD sure) and replace this pesky Dallas SRAM IC and then caps. Should I replace both electrolytic caps (I wish to replace them with solid state polymeric SMD caps) and this black one I don't know what type are they, seems that I've seen photos of them leaking to.
After I'm done with A5 board, I will go and check for HV and LV board and then recap A1 board.
The black rectangle box cap are tantalum, the ones that are affected are using common rounded smd electrolytic cap. Maybe a photo of your A5 will clarify that better.Well, unfortunately, I'm half a thousand kilometers away from my scope and I have no idea when I will return back. That what I'm doing now is preparing my road map for the feature, so I can do thins faster on the scope.
Actually, after googling a little bit and searching through SM a found that this a just regular general purposes tantalum 15 uF 25V 20% caps. And symbol "2" in circle is just a Vishay Sprague logo, nothing exciting here :(Yep, but they don't leak overtime and I think they should be pretty reliable.
Yep, but they don't leak overtime and I think they should be pretty reliable.Well, after reading this particular tantalum caps datasheet I came to conclusion that there is no need to change them. They have no lifetime parameter specified at all, so, probably, as they intact, I will live them. But I'm going to replace aluminum "wet" electrolytic caps on A5 with solid state polymeric "dry" caps. The have longer lifetime, lower ESR and have nothing lo leak out. And I have to replace this pesky Dallas SRAM chip, but that's no so easy to get a fresh one here in Moscow and I have to get a good programmer before.
Btw, for newly acquired 246x scope, suggesting to check these system voltage rails first at the J119 header when opening it for the 1st time.
Remember, get a big fan blowing the whole A1 board while its turned on without the enclosure to cool down those unobtainium hybrid ICs.
Of course ideally these rails should be measured with another scope instead of just ordinary DMM to see if the ripples are up to the specification.
The J119 header location and the voltages specification & tolerances required by the scope to work properly, quoted from Tektronix 2465B service manual.
Everybody, who's going to replace DS1225 SRAM chip should take a look at Dr. Hugo Holden's document, concerning this procedure and possible chip replacement with FRAM and DRAM. Defiantly worth looking at http://www.worldphaco.com/uploads/TEKTRONIX_2465b_OSCILLOSCOPE_CALIBRATION___REPOWERING_THE_DS1225.pdf (http://www.worldphaco.com/uploads/TEKTRONIX_2465b_OSCILLOSCOPE_CALIBRATION___REPOWERING_THE_DS1225.pdf)!
Turn off ID check and tell it it is a DS1225 and it probably will write to it.
Hey Franky, please take few photos if you had a chance, also the cal data zipped and attach it here as well, might be useful someday for someone, who knows.
Thats weird, my experiences with DS1225 either the old one and new were without any problem at all using the minipro I purchased from you. :-+
Heck, I even still use the old one, while the new DS1225 which already has the cal data copied into it is in the storage, just curious how long the old one will survive. >:D
Where did you buy that DS1225 ? Read few posts back, there was a similar problem with new "old" stock of DS1225 bought from a surplus shop if I'm not mistaken, and problem solved by using the new DS1225 from authorized distributor.
Fyi, mine was purchased directly from Digikey with quite fresh date code, whats yours ?
I just tested it some more and it looks like I can't write a "0" to the least significant bit of the high byte in each word. I can fill the chip with 10, 11, 12...1F, 30, 31, 32...3F, etc. but can't write 2x or 4x etc. :palm:BTW, did you checked old DS1225 for a multiple read sequence? It's not mentioned in document, but mr. Hugo told me that results MAY be different with data "fading" away more and more after each read attempt.
BTW, did you checked old DS1225 for a multiple read sequence? It's not mentioned in document, but mr. Hugo told me that results MAY be different with data "fading" away more and more after each read attempt.
How old is your original DS1225 is?
Regarding your problem writing to a newly purchased DS1225: I had the same experience with a DS1225Y-200 purchased from a local supplier (Jameco) despite its having a recent date stamp. Per advice given here, I bought another chip from Digikey - that one could be read and written to flawlessly.Could you provide us a photo of this two chips sitting one next to another?
Sigh ... Don't feel like to buy GQ-4X programmer just to program this fram, I guess I'm stuck with my TL866 and 3 pcs of unused FM1608s. :'(
Btw, thanks for the cal ram image. :-+
You description of the failure reading the Dallas NVRAMs after desoldering them from the board match what I experienced doing the same procedure on my 2440 which had a pair of DS1230 memories. My programmer would not work with the 20+ year old memories but did with the EEPROM based replacements that I used.
While testing to determine the problem, I believe I inadvertently overwrote the NVRAMs destroying the calibration data but the 2440 series external calibration is trivial compared to that of the 2465B series so I just did that after installing sockets and the new memories. If I had been working on a 2465B, I would have been more careful and persevered.
If I had been working on a 2465b or similar where the calibration is tedious, I would have been more careful and certainly tried accessing the backup battery directly so the calibration data could be read out. I wonder if raising or lowering the temperature would have been enough to access the data.
So for those with a lost memory and a non-working 2465B, could the scope use "generic" cal data?
I.e. how poor would the scope behave if one used cal data from an other working 2465??
So for those with a lost memory and a non-working 2465B, could the scope use "generic" cal data?
I.e. how poor would the scope behave if one used cal data from an other working 2465??
What percent of these humanely treated Tek scopes would make it to 2015 without needing any parts (other than a battery) replaced?
What percent would make it to 2020 without needing any parts replaced?
So I'm wondering if there are different versions of U800, (based on IC dates, scope was build in '94) or if the legendary U800 meltdown only happen with certain settings ?As far as I'm aware, currently only 2 versions, one made by Tek, another one from Maxim , posted both photos -> post #185 (https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg440178/#msg440178) while ago.
This time I will take some shots with my TIC.
I thought crest factor also had to be taken into consideration.
And since it was open (you need to calibrate the markers with pots), i also took a picture of my wannabee U800 cooler:
(http://members.home.nl/baltusg/u800.jpg)
So it is clear, the calibration signal should be a 1kHz square with 50% duty with the following values, 0.5V, 0.2V, 0.1V, 50mV, 20mV, 1V and 10V.
1) Are these voltages in 50 ohm or in high impedance ? I think is HiZ.
2) Yes voltages are peak-to-peak, are they 0 to 0.5V for or AC +/- 2.5V ? I think they are 0 to +0.5 but better check first before I do something stoopid :)
I also need to do a vertical cal on my 2465 and of course no PG506 .. I do have a nice working FG 504 very stable and nice, a 51/2 digit Fluke multimeter and some scopes to compare ... but I am scratching a bit my head at how the vertical calibration signal should look like.
...
1) Are these voltages in 50 ohm or in high impedance ? I think is HiZ.
2) Yes voltages are peak-to-peak, are they 0 to 0.5V for or AC +/- 2.5V ? I think they are 0 to +0.5 but better check first before I do something stoopid :)
Good question. I assumed they are 50 ohm impedance. Thea manual states the testing procedure switches to 50 ohm impedance in Cal 01, I just assume this carried over to Cal 02 (Vertical).
Good question. I assumed they are 50 ohm impedance. Thea manual states the testing procedure switches to 50 ohm impedance in Cal 01, I just assume this carried over to Cal 02 (Vertical).
It cannot always be 50 ohms because a PG506 will not generate 10 volts into a 50 ohm load.
Another reason it cannot be 50 ohms is that then the calibration amplitude would depend on the accuracy of the 50 ohm termination value.
Guido, that heatsink looks like a stacked coins to me. ;D
So it is clear, the calibration signal should be a 1kHz square with 50% duty with the following values, 0.5V, 0.2V, 0.1V, 50mV, 20mV, 1V and 10V.
I wish if there is an easy and relatively cheap to build such circuit, any experienced or experts want to contribute on the circuit schematic ?
Don't need to be high precision right ? <5% accuracy is enough maybe ? :-//
Good question. I assumed they are 50 ohm impedance. Thea manual states the testing procedure switches to 50 ohm impedance in Cal 01, I just assume this carried over to Cal 02 (Vertical).
It cannot always be 50 ohms because a PG506 will not generate 10 volts into a 50 ohm load.
Another reason it cannot be 50 ohms is that then the calibration amplitude would depend on the accuracy of the 50 ohm termination value.
The HP can output into HiZ ... just the voltage seen by the scope will be double. But then if you measure RMS with a mutimeter that is the same as seen by the scope . Of course if you have a square wave with 50% RMS value for 5V pk to pk is 2.5 . Same is my FG504 .. 50 ohm. At 1Khz reflections on the line are not something to worry too much about i think. Yeah many FG-s cannot go that low .. you don't need precision resistors .. just precision dividing any resistor of the right value and a multiturn pot/trimmer will do as ong as you have a good rms meter and a comparision scope you are set. We are not looking for ultra high precision and low tempco here .. if is stable for 5 mins until the cal step is done is good enough i guess
It cannot always be 50 ohms because a PG506 will not generate 10 volts into a 50 ohm load.
Another reason it cannot be 50 ohms is that then the calibration amplitude would depend on the accuracy of the 50 ohm termination value.
What would my best option be for attempting to calibrate with my HP8116a. It as far as I know can only output the stated output voltages at 50 Ohm.
Let's see how we go about making a differential comparator measurement. First, we establish a reference position on our display by grounding both inputs. Then selecting the appropriate input (positive voltage source to the + INPUT, negative voltage source to the - INPUT), we switch the other input to the comparison voltage (Vc). Next, the comparison voltage is adjusted until the trace "slides back" to the reference position. What have we accomplished? Using the "difference" principle we have introduced a "common-mode" condition in the form of the comparison voltage; that is, the comparison input voltage now equals the signal input. We see that we now have the ability to measure any potential whether it be DC, complex in nature, or a combination of both - such as a complex wave superimposed on a DC potential. Thus, we have an extremely versatile measuring tool.
Looks like to perform the differential comparator measurement as above a differential probe is needed?.
Well looked up on differential amplifiers and I am sure there is a way but way beyond me I am afraid, especially the complexity of one of the signals being AC.
How would you test to see if the U800 is having any issues?
I have no available this ICs on easy :(Really ?
It looks like Cypress is discontinuing their EEPROM based NVSRAMs. They still list them but their distributors do not have them available anymore and Cypress does not sell them directly.
Now having a new Dallas chip, I started of playing with my old ALL-07A programmer, and to my surprise it could not read/verify this chip. Odd... everytime I do access this new chip I do get a new checksum.
Now having a new Dallas chip, I started of playing with my old ALL-07A programmer, and to my surprise it could not read/verify this chip. Odd... everytime I do access this new chip I do get a new checksum.
Lucklily the old RAM still works and sits in my "scope".
@David
What did you end up doing then?? Give up and calibrate or managed to transfer the data to a new chip? If so what type of programmer?
The programmer I was using, listed the 1225 as supported, and still nothing. My take is there is a speed issue. Think the simplest thing would be for me to build a duplicator.
Use a address counter some glue logic and two 28 pin sockets. Make sure that the WR-pin is strapped to high to secure no write on source. Should be simple. Only thing is I will not have the data saved on file. Never mind...
CALIBRATION RAM EXAMINE (Exerciser 02). This routine allows the operator to examine the contents of 256 decimal locations, 00 (Hex) through FF (Hex), in RAM. When entered, the Exerciser displays the contents of RAM location 00 (Hex) on the top line of the CRT display. One hundred and seventy calibration constants reside between addresses 01 (Hex) and AA (Hex). Calibration constants residing between 01 (Hex) and 6E (Hex) should have odd parity as explained below. The remaining locations may be of either parity. The readout display line has the following format:
AA DDDD P
The format is defined as follows:
"DDDD" is the 14-bit word stored at that location (13 bits of data and one parity bit).
"P" is a parity indicator for the data word: X indicates even parity; blank is odd parity.
Pushing the upper or lower TRIGGER MODE switch will increment or decrement the RAM address by 16 (10 Hex) respectively. Similarly, pushing the upper or lower TRIGGER SOURCE switch will increment or decrement the address by 1 respectively.What puzzles me is that my programmer (supporting 1225) failed on a brand new chip... just wanted to verify programmer operation before plug in my precious old chip!I have a vague recollection that some NVRs have some sort of "factory seal" to maximise shelf life, and are activated by a special command to wake them up - could this be it?
The only thing I can come up with, except for a faulty chip, is that there are timing issues, programmer acting too fast some signals.
Hi,
Wondering if anyone has attempted to hand-copy cal constants using the "Calibration RAM Examine" thingie in the exercisers (or has at least verified that they are stored as shown in the RAM)...
-- looks like it's time to replace the NVRAM on mine soon and hoping that a hand copy of the cal data might give a backup in case something happens during the procedure (I'm a little leery due to past experiences with data loss when moving Dallas NVRAMs from board to board; in that case I think one of the boards had residual voltage on the + rail & it was probably more user fail than IC fail... but still makes me hesitate).
best case would seem to be that those 340 bytes are just stored on the NVRAM starting at address 1 - and that if one takes a blank NVRAM and writes only those bytes, that nothing else will be required to make the scope happy (e.g. no other checksums or other data required for the scope to see that it's calibrated and work properly).
This one is for BravoV. I have the same vertical geometry problem you had [the words are too low to read]
You said that you adjusted the vertical readout trimpot.
I cant find this "vertical readout trimpot" in the schematics or troubleshooting. I cant even find those words in a 2445B or 2465B service manual.
Could you tell me what R number you adjusted? :)
Wondering if anyone has attempted to hand-copy cal constants using the "Calibration RAM Examine" thingie in the exercisers (or has at least verified that they are stored as shown in the RAM)...I did this with my 2465, but I took a more lazy approach. I took a video of the screen while flipping through all the memory locations.
Cool -- though do you know whether the constants can just be copied into a new IC and have it work?No, I don't know. I'm assuming it's accurately reporting the word at each location. I'll have to test reprogramming in battle.
The calibration constants from exercise 2 are located at addresses 1E00 - 1FFF in the NVRAM. I don't know if they can be used with another dump. Maybe I will try just out of curiosity. Maybe I will able to tell which constants are for vertical calibration when I calibrate the vertical.
I will post some pictures of the process when all the tasks are done.
Update: I have just tried a 2465B S/N B05xxxx dump on my 2445B S/N B06xxxx with my original calibration constants. It works flawlessly! So, it is a good idea to backup your constats from exercise 2 before you do anything with the NVRAM chip. It can save you a calibration if something goes wrong when you try to read your NVRAM after desoldering.
Malch, remember, I'm NOT the expert on this problem, and "maybe" my method is not the right way to fix this problem. So proceed with your own risk.
My suggestion, read the service manual, and understand what these 2 pots do. Also use a sharpie/marker to mark the current position at the pot, so if you suspect you screwed up ??? while adjusting these pots, you can turn it back to the previous position.
1E: reset status
--- DS1225Y NVRAM copy programmer ---
Select:
[R]ead NVRAM into PIC flash
[V]erify NVRAM with PIC flash
[W]rite PIC flash to NVRAM
erase PIC [F]lash
erase [N]VRAM
[B]lank check PIC flash
fill NVRAM with ran[D]om data
fill PIC flash with rand[O]m data
[P]rint NVRAM contents
print PIC f[L]ash contents
get [C]hecksums
> R
Erasing flash...
Reading 1F00
Read completed.
Verifying 1F00
Verify completed: success.
--- DS1225Y NVRAM copy programmer ---
Select:
[R]ead NVRAM into PIC flash
[V]erify NVRAM with PIC flash
[W]rite PIC flash to NVRAM
erase PIC [F]lash
erase [N]VRAM
[B]lank check PIC flash
fill NVRAM with ran[D]om data
fill PIC flash with rand[O]m data
[P]rint NVRAM contents
print PIC f[L]ash contents
get [C]hecksums
> C
NVRAM checksum=0xF9AB
Flash checksum=0xF9AB
--- DS1225Y NVRAM copy programmer ---
Select:
[R]ead NVRAM into PIC flash
[V]erify NVRAM with PIC flash
[W]rite PIC flash to NVRAM
erase PIC [F]lash
erase [N]VRAM
[B]lank check PIC flash
fill NVRAM with ran[D]om data
fill PIC flash with rand[O]m data
[P]rint NVRAM contents
print PIC f[L]ash contents
get [C]hecksums
>
1E: reset status
--- DS1225Y NVRAM copy programmer ---
Select:
[R]ead NVRAM into PIC flash
[V]erify NVRAM with PIC flash
[W]rite PIC flash to NVRAM
erase PIC [F]lash
erase [N]VRAM
[B]lank check PIC flash
fill NVRAM with ran[D]om data
fill PIC flash with rand[O]m data
[P]rint NVRAM contents
print PIC f[L]ash contents
get [C]hecksums
> W
Writing 1F00
Write completed.
Verifying 1F00
Verify completed: success.
--- DS1225Y NVRAM copy programmer ---
Select:
[R]ead NVRAM into PIC flash
[V]erify NVRAM with PIC flash
[W]rite PIC flash to NVRAM
erase PIC [F]lash
erase [N]VRAM
[B]lank check PIC flash
fill NVRAM with ran[D]om data
fill PIC flash with rand[O]m data
[P]rint NVRAM contents
print PIC f[L]ash contents
get [C]hecksums
> C
NVRAM checksum=0xF9AB
Flash checksum=0xF9AB
--- DS1225Y NVRAM copy programmer ---
Select:
[R]ead NVRAM into PIC flash
[V]erify NVRAM with PIC flash
[W]rite PIC flash to NVRAM
erase PIC [F]lash
erase [N]VRAM
[B]lank check PIC flash
fill NVRAM with ran[D]om data
fill PIC flash with rand[O]m data
[P]rint NVRAM contents
print PIC f[L]ash contents
get [C]hecksums
>
Make sure you get "W" FRAM. FM18W08 or FM16W08. These lasts 100 times longer (10E14 cycles) then devices without "W" (10E12 cycles).
I have not seen "W" devices on eBay. And, I prefer to buy from well known reseller (Farnell, Digikey, Mouser) than eBay.
.... 16k years to wear the device out.
Yes, I am.
Are you sure...
Both are rated for 1014 operations.No, they aren't. Look again.
No, they aren't. Look again.
Here's FM1608 datasheet:
http://www.farnell.com/datasheets/82469.pdf (http://www.farnell.com/datasheets/82469.pdf)
And here is FM16W08 datasheet:
http://www.cypress.com/?docID=48242 (http://www.cypress.com/?docID=48242)
On page 3 BravoV posted this
"Sad news, a failed to attempt to find the better replacement for the pesky Dallas DS1225Y BBSRAM, cause the F-RAM Ramtron FM1608-120 is not compatible. It was an impulse purchase thru a friend visiting abroad without checking the detail 1st, and also I was mis-leaded by info gathered from the Tektronix's Yahoo mailing list"
How come his chips didnt work but yours does?
But it didnt work in BravoV's case. ?
Now, go to eBay, seek for "FM1608", and all the parts you will get will be Ramtron ones.I'll agree with you as far as "from eBay, you cannot know what exactly you are buying" :)
Then, do the same with "FM16W08", and you will again get some Ramtron devices.
Then, on the Cypress page, look for "FM1608", and you will get nothing. 16W08 is there.
So, in practice, buying FM1608 from eBay, you cannot know what exactly you are buying - a device with 10E14 or a device with 10E12 cycles. Buying 16W08 you are sure it is 10E14.
P.S: I would like to see that datasheet for 1608 with 10E14 rating. I cannot find it anywhere. Can you please give a link or upload it here?Now I look it's a FM1608B http://www.cypress.com/?docID=48234 (http://www.cypress.com/?docID=48234), Cypress don't currently list an FM1608, as you say.
Sorry - it's splitting hairs and for that I apologize - but you know how it is (http://www.xkcd.com/386/) >:D (actually that's a bit unfair as you weren't really wrong)There's nothing to apologize for. :)
Well all done. Moved the cal/nocal jumper to cal and fired it up.
The 10 v was out a little [9.98 v ] and I had to fiddle with the vertical jitter pot.
Ran test all and all passed.
What is the exerciser used for ? How do you know when it is finished? How do you stop it?
Finished my U800
This is the best series of posts on EEVBLOG! Very informative, and interesting. My 2467B is on it's way from NYC off ebay. Cannot read SN well, but looks to be starting 05, so probably has the Dallas. Cannot quite read what is showing on the CRT either, so unknown if it has error messages. Seller did not seem to really know much. I figured out from the fuzzy rear photo that it has Option 05 TV Sync Sep, Option 06 CTT, Option 11 Probe Power. Can't wait to get it, open it, and see what's up... leaning toward the big battery option for the Dallas.
Martin
Wikipedia notes 01E is for joining two scopes with one sync pulse.
As usual, I'm late to the party! I haven't read the extensive posts here, so please forgive me if I'm repeating stuff you already know. I have a 2465 that had some problems a few years ago. It reported a earom failure. Turned out it was the electro for the -42V rail in the power supply. I went through and did an ESR test on all the caps on that board and all but one cap was ok. I disassembled the code and found where the earom was accessed. Shouldn't be too hard to poke in some code to use a modern spi eeprom. Since I found the root cause, I had no need to do any mods.
One problem I had recently is the power switch. This looks like a standard ITT shadow part that was common years ago. Does anyone know where to source these at a reasonable cost? As in around $10-20 USD? I've just put wires across the switch for the moment and power off by pulling the plug.
The time out on the CRT brightness on my 2467B seems to be 30secs according to the screen. Is this normal? Pretty silly having to turn a knob every 30 secs to keep the display on!!!
The time out is a normal feature I think on the 2467B, just not sure if 30 secs is the default, and if that can be changed. No, it makes no difference on the intensity setting, still 30 secs countdown, no matter what. I'm sure it saves burns, but quite annoying!There are two timeouts, one to dimming and the other to "shutdown" (as far as I cans see this is just a sleep mode, the scope comes back immediately when you hit a button).
Sorry, I am no expert, if Alan w2aew comes by I am sure he will be able to answer far better than I can.
What does happen is that the readout text ever so slightly dances around the CRT, a pixel or two horizontally and vertically, at certain times, and it is by design. Unless I'd read about it in the manual, I probably wouldn't have noticed it to think anything much about it.
The other thing that happened, was I found out I need an angiogram, maybe a stent, or even bypass surgery.Well at least the stress of the Tek has passed now.
Maybe it's a really good thing... I might live to use the damn thing! :)
Studied that bridge ckt. with the adjust pot, found R2013 10k COMPLETELY open. There was a small amount of electrolyte leakage from the caps, but this area looked perfect! No idea why that resistor would open!
sparkybg,
I have a 2445B I recently acquired that I am in the process of repairing (channel 1 trace dead). Once I get that sorted out, I plan on doing the capacitor change out on the PS and A5 boards (no indication of leakage at this time). Since I will already have the A5 board out, I plan on also removing the Dallas chip, and replacing it with the Fram FM16W08 chip and adapter board. I have made a video of the current EXER 02 settings (thanks for the idea Markl) since it is probable that I will loose the settings (25 year old battery). Back in mid Jan in this thread you discussed doing some NVRAM programming using the FRAM chips, and I have been reading that info with much interest. I also have a programmer that will work with both the Dallas chips and the FRAM chips. I have already downloaded a copy of the bin file for a 2465B and have been examining the file structure and information contained in the file using the program that came with my programmer. Your posts back then showed the calibration info from the 2465B would work in a 2445B with the appropriate data modified. I have programmed a couple of chips in my day (20 years ago), but I am having some difficulty in understanding how the EXER 02 data correlates to the HEX data in the downloaded file. Is it possible that you could give me a brief explanation on how the two data sets compare. Thanks in advance for any assistance.
Mitch
The calibration constants from exercise 2 are located at addresses 1E00 - 1FFF in the NVRAM.
Wikipedia notes 01E is for joining two scopes with one sync pulse.
Hi, checked Wiki, but only found this...
Oscilloscope Options
The important oscilloscope options are:
01 - Digital Multimeter
03 - Word Recognizer Probe Pod (P6407)
05 - Video Waveform Measurement System
06 - Counter/Timer/Trigger (CTT)
09 - Counter/Timer/Trigger (CTT) with Word Recognizer (WR)
10 - GPIB Interface
11 - Probe Power
1E - External Clock
22 - Two additional Probes
1R - Prep for rack mounting kit
I have a tek 2445B scope that has the dreaded test 05 44 error which says a voltage is too positive. Question 1, is this the right to ask this question and if so where or how do I find that voltage so I can understand why it is to high. I checked all the voltages on the J119 IC socket and found all were within spec. Also what on the main PCB would cause such an error. :)
All, Im going to move my posting over to the Repair section under a different thread so I am not hijacking this one.
Thanks for the responses. Stupid me didn't realise tektronix have the part numbers in the service manuals!Did you manage to find a suitable replacement for your power switch? The switch in my 2465B is failing as well (arcing, sticking and sometimes giving of that fine odor of burning phenolic). There are still manufactures making that form-factor of switch, but I haven't had a chance to tear the unit down, and do the necessary measurement to find a replacement.
Howardlong I sent you a PM.I cant make the PM work. :(
Howardlong I sent you a PM.I cant make the PM work. :(
Dont worry about what the Rigol fundamentalists say, they dont know quality when they see it.
Question Re: Dallas Chip Replacement
I recently picked up a 2465B locally, serial BO57xxx. The scope will only be used for hobby purposes, and I know nothing about programming an IC (and would prefer not to make this scope my first experiment in programming an IC). As a preventative measure, does it make sense to buy a pre-programmed IC (e.g., from the seller in Greece) and replace the existing chip with the pre-programmed chip or would it be better to have someone copy the info from my chip info to a new chip? What functionality/calibration information of potential significance to a hobbyist, if any, is lost by replacing the Dallas chip with a new chip pre-programmed with "basic" settings? Thanks.
Question Re: Dallas Chip Replacement
I recently picked up a 2465B locally, serial BO57xxx. The scope will only be used for hobby purposes, and I know nothing about programming an IC (and would prefer not to make this scope my first experiment in programming an IC). As a preventative measure, does it make sense to buy a pre-programmed IC (e.g., from the seller in Greece) and replace the existing chip with the pre-programmed chip or would it be better to have someone copy the info from my chip info to a new chip? What functionality/calibration information of potential significance to a hobbyist, if any, is lost by replacing the Dallas chip with a new chip pre-programmed with "basic" settings? Thanks.
the Greek Dallas is screwy for sure because if I load on any of the .BIN files previously uploaded from this 2465 Teardown topic, it works fine with the scope (although would still need a CAL of course). Yeah, I should at least get a refund for the programming part of that Dallas.
...RF and other high frequency sources are typically terminated in 50 ohms. If it's not terminated (or loaded with a very high impedance like the scope 1M input), the amplitude will be double.
When I try to measure a sine wave signal, then things get a bit more interesting. Having a known RF signal of a know amplitude, the scope reads quite a bit higher than I think it should. About twice the expected value. I still have a lot to learn about the operation of the scope. Might just be operator error. I'll figure it out eventually.
Mitch
MarkL,If I understand your setup, you would actually have *two* 50 ohm terminators. One in the Tek scope and one external on the other scope. So that would be 25 ohms because they're in parallel.
I got a chance to play with the scope some more this morning. I fed the output of a Boonton 103D signal generator (.125mhz to 175mhz) set at 10mhz to a T connector which went to two different oscilloscopes. The 2445B and my Kenwood CS-5170. I bought the CS-5170 new in about 1996 or so. So I have a high degree of confidence in its accuracy. I set the 2445B to 50 ohms coupling, and used a 50 ohm feed through termination on the CS-5170 and compared both displays. Both scopes read exactly the same (within a couple of decimal points) in both frequency and amplitude. These readings also agreed with the expected output of the signal generator. So it looks like at least for these simple tests that the scope is working as expected. One test down and many more to go.
MarkL,Hi Mitch,
You are correct in regards to the miss match. What I was trying to state is that the amplitudes and wave forms were the same on both scopes. Yes the amplitude was off, but I was trying to see if the 2445B responded the same as my CS-5170, which was the case. I'll round up a 50 ohm splitter and replace the BNC T with it. Or just run the one 50 ohm termination and see what the scope shows. I'll have to pull down one of my Boonton 92C RF Millivolt Meters and measure the output so I have a good reference. I know the output meter on the 103D is not calibrated and is out by some amount. It was originally a 75 ohm unit. After inspecting the schematic, I discovered that the only difference between it and the 50 ohm version, is that it had a 50 ohm to 75 ohm unun in line with the output. I even have a new 50 ohm meter face that I need to install then do a cal on it.
Mitch
OK I couldnt stand it anymore. I took my 2445B apart and this is what I found.
C1113 and C1116 are 180uf/40v
C1114 and C1132 are 250uf/20v
C1120 and C1130 are 10uf/100v
C1115 is 10uf/160v
C1132 and C1115 are flipped in the service manual.
Everybody take note, make a note and stick it to your scope. Ohh shit it rhymes. :palm:OK I couldnt stand it anymore. I took my 2445B apart and this is what I found.I would imagine then that this affects 2445B, 2455B, 2465B and 2467B, all of which share that same inverter board, although I searched online and couldn't find board layout diagrams specific to all those models, I only have the service manual (including layouts etc) for the 2465B and 2467B.
C1113 and C1116 are 180uf/40v
C1114 and C1132 are 250uf/20v
C1120 and C1130 are 10uf/100v
C1115 is 10uf/160v
C1132 and C1115 are flipped in the service manual.
Edit: I guess we should be clear that they are only flipped in the board layout diagram, fig 10-13. The schematic and BOM are correct.
MarkL,I think you're right. The Amprobe AM530 spec sheet says its frequency range is only to 400Hz and it's unclear if that's a 400Hz sine wave 3dB point or the meter is good for measuring some number of harmonics past 400Hz if you're working with 400Hz AC line current. Since you're using it to measure 1kHz, you can be suspicious of whatever reading it's giving you. You could try 50Hz and see if they agree more closely.
You read correctly. I did some more checking, and realized I was sending a 50 ohm RF sine wave (10mhz) signal into the 1meg ohm scope input. That had things all messed up. I did some more testing this morning with the function generator set to 1khz square wave, and sampling the output with my Amprobe AM530 DMM, (which is supposed to be a true RMS meter). This signal was fed into the scope set to 50 ohm coupling. I expected to see about twice on the scope display as what I was seeing on the DMM, which is roughly what I saw. Actually the scope reading was a bit more than twice the DMM reading. Both of my scopes read very close to each other, so I think the scope reading are good, but the DMM reading may not be as accurate as I would like.
...
MarkL,Most DMMs don't go very far in RMS frequency. Some of the best top out at a few hundred kHz. And even then, the accuracy can be quite poor at the upper end.
I knew it was something simple. For some reason I was thinking the Am-530 went to 400khz, not 400hz. That would explain the discrepancies I have been seeing. I can try a lower frequency, or better yet, get a DMM that can handle higher frequencies. Any reason to get more test gear!!!
I need to go review the posts in the forum on DMM's.
Mitch
All,
My scope is currently fully assembled, so I could not look at the inverter board. However, I did consult my 2445B manual (also covers 2455B) and saw the same component size mismatch as shown in previous posts. I also have a copy of the service manuals for the 2445 and the 2465. Those have the diagrams with the physical size correct, but positioned slightly different. According to all three manuals I have, the parts list C1114 and C1115 as the same value. When looking at the 2445 board layout, the physical size of both C1114 and C1115 are the same, with C1132 being physically smaller. According to what I see in my manuals, C1132 is supposed to be 10uf@160v, C1115 is supposed to be 250uf@20v.
Mitch
I have a printed copy of the "2445/2465 Option 06 and Option 09 Counter/Timer/Trigger and Word Recognizer Service Manual", pub #070-4632-00, so I can say the service manual is not the same.Dredging up this old thread...
knobs, shaft extenders, and pots. How much???
Sent the PM. not seeing responses... :-/O
Anyone have the Digi-Key parts list handy for a power supply re-cap?
Sent from my Tablet
Has anyone here actually entered calibration data recorded from the scope Exer 02 display onto a generic NVRAM file ( to correct its calibration data for your scope) and successfully used the new chip? Part of this question involves relating data addressing on the new file as shown on a typical hex editor.
You know, I wonder if it would be possible to take the main A1 board out of a 2465X, put it in another scope, do the cal and then move the board and NVRAM back to the original scope. That should work, right? As all the analog stuff is there. If so, that could make it a lot easier for people without the equipment to get their unit calibrated, as you wouldn't need to ship the whole scope back and forth, just the main board. Hmmm.
...<snip>... I managed to get it for free.
...<snip>... I managed to get it for free.
I hate you. LOL ...j/k >:D
Congrats on the score. :clap: :-+
If anyone in the VA/NC area needs a scope cal, I've got a calibrated PG506, SG503 and TG501 to do it with. You just need to bring your scope over.
You know, I wonder if it would be possible to take the main A1 board out of a 2465X, put it in another scope, do the cal and then move the board and NVRAM back to the original scope. That should work, right? As all the analog stuff is there. If so, that could make it a lot easier for people without the equipment to get their unit calibrated, as you wouldn't need to ship the whole scope back and forth, just the main board. Hmmm.
Sent from my Tablet
Anyone have the Digi-Key parts list handy for a power supply re-cap?
Sent from my Tablet
Here's the file posted to the Yahoo Tek scope forum. Mouser and Newark part no.s only though.
https://dl-web.dropbox.com/get/_2465LVPS_ReCap%2C%20A1%20recap-parts.xls?_subject_uid=315056499&w=AABBEwsyvXv8-MkXuvQXylKApXyus6nBmOsuJ0r-fgUkYw
Anyone have the Digi-Key parts list handy for a power supply re-cap?
Sent from my Tablet
Here's the file posted to the Yahoo Tek scope forum. Mouser and Newark part no.s only though.
https://dl-web.dropbox.com/get/_2465LVPS_ReCap%2C%20A1%20recap-parts.xls?_subject_uid=315056499&w=AABBEwsyvXv8-MkXuvQXylKApXyus6nBmOsuJ0r-fgUkYw (https://dl-web.dropbox.com/get/_2465LVPS_ReCap%2C%20A1%20recap-parts.xls?_subject_uid=315056499&w=AABBEwsyvXv8-MkXuvQXylKApXyus6nBmOsuJ0r-fgUkYw)
Link doesn’t work for me. Says I’m not logged in, despite being logged in.
Why not just zip it and attach here, it will be useful reference for others in the future, sorry , don't have dropbox account.
I feel like I'm banging my head against a wall with this thing. Turns out the fan was a broken wire. No big deal, fix, reassemble and now something is seriously broken.
Upon power up, all the front panel lights come on and stay lit. No readout or trace, no relay clicks, nothing. All rails are slightly low, so something is seriously pulling power, but not enough to trip the current. +5VD is the worst, there's 300mV ripple in the shape of a triangle wave on it.
I used my HP current tracer probe, but nothing appears to be pulling any serious power on the digital board.
I'm getting a 1.25MHz clock on the MPU pin, but the IRQ pin is toggling at like 100ms, instead of the few microseconds listed in the troubleshooting chart. Could be the aforementioned ripple though.
I guess first step is to build a load for the PS and test the rails. If that checks out I guess I start tracing signals.
*Sighs*
Sent from my Tablet
The IRQ input should be 10us for every 3.3ms according to the flowchart. A 1.25MHz processor couldn't possibly respond to an IRQ with a continuous period of only a few microseconds.
You could also take a look at the reset circuitry for the processor. Iif you have instability on the +5V supply, it could be causing continuous resets.
But I would agree the 300mV ripple on the 5V supply is the main concern.
The DMM option is a total train wreck. The DCV spec'ed accuracy is 0.03%. Not even close. Example: with my 1.000 VDC standard it reads 0.9886 V on autorange. If I go up one range it reads 1.000 V. The kernel/confidence tests do not check the DMM cal directly other than basic functions. The service manual states to perform a cal if you suspect an issue. I did do some extensive resistance checking of the input networks just in case something was fried and found nothing. Proper calibration of the DMM option requires a Fluke 5101 with calibration constants ranging from .19 V to 450 V. As I stated before I'm just a hobbyist and there is no way I'm going to be able to get a Fluke 5101. I don't really consider this function important anyway since I have a Fluke 87 and a Fluke 8021B that take care of my needs.
So, my first approach will be to 1) replace the bad parts, 2) recap the board and possibly replace some of the resistors identified by dehav7 and 3) replace R6190 with C6190 to install option 1E. I am currently pulling together a parts list for Mouser. I would also like to replace the soldered in Lithium battery. Does anyone have a suggestion on how to do this without losing calibration data? Can I socket that? I don't currently have the equipment to perform a calibration so I don't want to risk losing the calibration data.
You have to bridge in the voltage while changing out the lithium battery or you will lose the calibration data. I forgot where I saw the procedure. If I find it I'll post the link. My older 2465 DMS has NVRAM so no battery issues.
Looking forward to your teardown. So far I haven't had any power supply issues but I know that day will come where I'll have to recap to inverter and power supply boards. So far all the voltages are in spec.
One "gotcha" regarding the DMM option. The power up self checks do check some basic DMM functions but will NOT flag the DMM calibration. The DMM option manual states to perform a calibration if you suspect it to be out of spec. That's exactly what I found out as I posted in this thread. If you find the same with yours I can give you some pointers on how to get a reasonable calibration cheaply :-+
To replace the battery, you can use a procedure described in the Yahoo Tek Group, well described in four pictures.
You can also use a bench PSU to back-up the battery while replacing it, but be careful not to have it grouded to earth because your soldering iron would then make a beautiful short when you solder the positive pin... In this case you can unplug your iron for the time of the soldering.
3. I wanted a unit with the frequency counter because I need one. Option 09 gives 7 digits without an external time base and 8 digits with. Since my next purchase will be a GPSDO that is more than sufficient in terms of accuracy. Anything more than that - or even to match it - would be very expensive. So that narrows the field down to the BCT, BDM or BDV. Also, I have very limited space on my work bench and the integrated frequency counter helps there as well.
I may need pointers on the tear down. I haven't taken out any board yet that requires desoldering. I have had the options out several times. There are two areas where it is a pain. First is the ribbon cable that tends to get pinched. It is hard to get that in right. The second is the two cables at the very end which go onto the same pins. It is not clear which cables go where. I figured that out because one of the pins goes to the resistor / capacitor that I will be changing for option 1E, but the manual is useless there.
Yep, Option 09 is definitely a nice feature and I use it all the time. But keep in mind that the frequency counter is only good out to 150Mhz which is odd when you consider that the bandwidth of the scope is double that.
I have yet to do a tear down too. And I have the additional DMM board across the top of the chassis. Luckily it swings to one side and can be removed.
I've also had issues locating all the service and operating manuals. I have the vanilla 2465 ops and service manual. I have the DMM service manual but no ops manual. And no options ops or service manual but I did find the 2465A options service manual and 2465B options ops manual but they are only good for some reference because of the changes TEK made over the years.
It's good to 200MHz, not 150MHz.
It's good to 200MHz, not 150MHz.
I think that depends on whether it's a 2465, 2465A, 2465B. I have the Tek 1986 Product Catalog which describes the 2465 and, unless I'm reading it wrong, the counter option is good for 150Mhz. I don't have a signal source greater than 100Mhz so I can't test it. But it would make sense that it would increase in response since the 2465A B/W is 350Mhz and the 2465B is 400Mhz.
I couldn't manage to embed the pictures, so I have attached them. Also .jpeg files are not allowed! WTF! And apparently only tiny files are allowed! So, one per post. Sigh.
I couldn't manage to embed the pictures, so I have attached them. Also .jpeg files are not allowed! WTF! And apparently only tiny files are allowed! So, one per post. Sigh.
Your pictures are too big. Use a program such as "IrfanView". Resize images to 1920 x 1080. Save. Then you should be able to upload each pix in one post.
P.S. I prefer to upload high resolution images. Extremely low resolution images such as 1920 x 1080 are annoying when you want to zoom in on the detail (which is something I do all the time and assume that other people do as well). I would rather not have compression used at all, but uploads are limited to 1M per file so a full resolution image of 25M or so doesn't work. I should have done two per post, though.
I couldn't manage to embed the pictures, so I have attached them. Also .jpeg files are not allowed! WTF! And apparently only tiny files are allowed! So, one per post. Sigh.
Your pictures are too big. Use a program such as "IrfanView". Resize images to 1920 x 1080. Save. Then you should be able to upload each pix in one post.
Yeah. They need to be resized first. Or try something like www.imgur.com (http://www.imgur.com) which should take care of resizing and give you (img) tags you can can copy and paste.
It's blurry because the camera has focussed on the front of the knobs (the "var" is in focus on the three knobs) and there is little depth of field. The photo of the rear of the 'scope is actually quite sharp, not very exciting viewed at the actual pixel resolution though.P.S. I prefer to upload high resolution images. Extremely low resolution images such as 1920 x 1080 are annoying when you want to zoom in on the detail (which is something I do all the time and assume that other people do as well). I would rather not have compression used at all, but uploads are limited to 1M per file so a full resolution image of 25M or so doesn't work. I should have done two per post, though.
Huh? Resolution is only useful when the actual image supports it. That picture is nowhere near sharp enough for a 5269x3573 resolution to be useful...did you even look at it? It's blurry! You're just wasting bandwidth and server space and annoying people on slow connections...
I size my photos based on the actual level of detail in the original. Works much better.
Hello,There's a good Tek pdf with a section on troubleshooting SMPS in this thread:
I am new in the forum am I find this blog very interesting.
I have searched about restoration of Tektronix 2465B PSU but I could find anything about it.
For this reason I write here, I hope not disturb. Well, at the present time, I am trying to repair the PSU of this wonderful scope but I could not more. I recap this stage and changed other parts but the PSU is now in a tick mode. Please someone could me help and explain why this happends and how could I go out of this mode? ....I do not know what to do... I hope you can help me with this...
Thank you in advance..
Hello,
I am new in the forum am I find this blog very interesting.
I have searched about restoration of Tektronix 2465B PSU but I could find anything about it.
For this reason I write here, I hope not disturb. Well, at the present time, I am trying to repair the PSU of this wonderful scope but I could not more. I recap this stage and changed other parts but the PSU is now in a tick mode. Please someone could me help and explain why this happends and how could I go out of this mode? ....I do not know what to do... I hope you can help me with this...
Thank you in advance..
Hello,
I am new in the forum am I find this blog very interesting.
I have searched about restoration of Tektronix 2465B PSU but I could find anything about it.
For this reason I write here, I hope not disturb. Well, at the present time, I am trying to repair the PSU of this wonderful scope but I could not more. I recap this stage and changed other parts but the PSU is now in a tick mode. Please someone could me help and explain why this happends and how could I go out of this mode? ....I do not know what to do... I hope you can help me with this...
Thank you in advance..
Best thing you can do is download the service manuals. They are invaluable and the troubleshooting steps for the power supply are very good. Failing that join the Tektronix's group on yahoo. That's where the Tek experts/enthusiasts hang out.
https://groups.yahoo.com/neo/groups/TekScopes/info
I had a issue with a power supply on my 2465B and if it wasn't for the help on the group never would have figured out the problem. Aged and out of spec opto-isolator. Note if you recapped there is a error on the schematic and likely one of the caps was inserted backwards, can't remember which though.
Here is the damage, apparent bad components and recapping of the A3 Inverter board for my 2465B CT scope.
You have hidden all the brand names. :-// On purpose?
Replaced capacitors
(http://imgur.com/GlV9bub.jpg)
RIFA, Nichicon, Sprague and Cornell Dublier is my guess.Sure, but why guess?
You have hidden all the brand names. :-// On purpose?
Replaced capacitors
(http://imgur.com/GlV9bub.jpg)
How many were faulty?
Care to list them for us?
What do need them for? I have the complete parts list, with replacements that I have previously posted. There have been some updates as I have worked on each board. Do you need the updated list? I will be posting that later, but was going to wait until I have complete finished.Only information for this thread:
I have knob problems with my 2465B CT scope. On the front panel, the two bottom halves of the VOLTS / DIV knobs have set screws that are stripped. Probably because somebody screwed them in far too tight. How do I get these off, and where can I get either a knob replacement or a set screw replacement (assuming I get them off without damaging the knobs)?http://www.sphere.bc.ca/ (http://www.sphere.bc.ca/)
Additionally, two of the smaller knobs with a blank front (e.g. like the TRACE SEP knob) and two of the smaller knobs with a line on the front (e.g. like the POSITION knobs) have their internal "cap" broken. These are my fault because they were on so tight I had to pry them off with a screwdriver. Unlike the ones under the CRT, which came off with just finger pressure, all of the knobs on the main panel were stuck really badly. Where can I get a knob replacement for these?
These knobs are common to pretty much all of the 22xx and 24xx series, so I would think that they are out there somewhere.
Thanks.
I have a 2465A, which has the digital board similar to the earlier 2465B serials, that is, with through hole components, and with the separate SRAM and battery, rather than a DS1225 module. My calibration data is intact but the battery is original, so I can assume that it will not be intact for too much longer.
The separate SRAM/battery is a mixed blessing: on one hand I can more easily desolder and replace just the 4 pin battery a 28 pin NVSRAM. On the other hand, I have no way to read out and save (or restore) the calibration data itself. After browsing the service manual, I got the idea to put the processor into the diagnostic NOP loop. It will cycle through all addresses on the address bus, with the intention of allowing the testing of address bus and decoding (chip selects). I thought that the data could be captured by using either a logic analyzer or by piggy-backing an NVRAM and supplying write pulses for each address so that it captures the data that the SRAM presents to the bus when it is addressed. One issue is that I don't have a logic analyzer. Does anyone have an opinion about either of these methods? Should I just replace the battery and cross my fingers that I'll never need to restore the data?
Tektronix had a change in their manufacturing process. At one point they closed their hybrid production plant, or it was sold to a subsidiary of Maxim.
When Maxim started to produce the U800 for Tek, the troubles were introduced. The bad chips are having the maxtek marking, and not the Tek marking on them.
There is a reliability report floating around on the internet with statistics on this chip, made by Maxim.
Basically what happens is the the die comes loose from the heat sink. if this happens, you will notice a gradual shift of the characters on the screen to the left on power on.
If this situation continues, eventually, the chip burns out....
In my scopes all U800 got an heat sink, despite the fact that they all were Tek branded. Be aware that the IC heat sink is a -5.2 volts
Added link to Maxim report https://www.maximintegrated.com/en/qa/reliability/general/RR-B2A.pdf (https://www.maximintegrated.com/en/qa/reliability/general/RR-B2A.pdf)
FireDragon:
Typically the recommendation is to avoid recapping the mainboard. Can't recall the specific reasons why, think it had to do with issues of the multilayer PCB. in any event good job, did you notice any improvements in performance in recapping the main board.
Here is the damage, apparent bad components and recapping of the A3 Inverter board for my 2465B CT scope.
Additionally, on the A3 Inverter board there are three more RIFA capacitors and it can be seen that all three are cracked. They may still be working, but probably not for long. The A3 Inverter recap does not include those because I need to order replacements. It can also be seen looking at the bottom on the replaced capacitors that one looks like it was starting to leak, a second appears to have damage to the bottom (pre-leak?) and I am not at all sure if some of the rest are slightly bulging or not. They certainly aren't completely flat, but that may be a construction difference.
A3 Recapped Inverter Board (http://imgur.com/pnUyrOJ.jpg)
Welcome to the forum.Here is the damage, apparent bad components and recapping of the A3 Inverter board for my 2465B CT scope.
Additionally, on the A3 Inverter board there are three more RIFA capacitors and it can be seen that all three are cracked. They may still be working, but probably not for long. The A3 Inverter recap does not include those because I need to order replacements. It can also be seen looking at the bottom on the replaced capacitors that one looks like it was starting to leak, a second appears to have damage to the bottom (pre-leak?) and I am not at all sure if some of the rest are slightly bulging or not. They certainly aren't completely flat, but that may be a construction difference.
A3 Recapped Inverter Board (http://imgur.com/pnUyrOJ.jpg)
I've been following this thread for days now, including all the links to other information. This is a great thread full of good information and populated with great posts. Thanks to all of you who have contributed here.
FireDragon, it appears as though you may have fallen prey to a documentation error. Specifically, on the A3 inverter board, the documentation has the info for C1132 & C1115 reversed. It may just be the picture you've provided, but it's worth checking it out.
See this post from HowardLong https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/475/ (https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/475/) for complete information.
Again, I've been very impressed by the content and quality of this thread.
FireDragon, it appears as though you may have fallen prey to a documentation error. Specifically, on the A3 inverter board, the documentation has the info for C1132 & C1115 reversed. It may just be the picture you've provided, but it's worth checking it out.
Damn .. what happened to those toasted resistors ? :o
Are their resistances still within the printed values especially for those are not toasted ?
Btw, thanks for the contribution to this thread. :-+
RT1010 and RT1016 are negative temperature coefficient thermistors. They have a high resistance when cold to limit surge current when the unit is first turned on, then their resistance drops as they heat up to allow adequate current flow to the power supply. Perhaps one or both have failed shorted, or drop resistance too fast etc. If they allow too high an initial surge current, you certainly could blow the fuse.
Do they meet their cold specification?
I have no idea how NTC thermistors age or typically fail. Since at room temp they are close to their specified resistance, I'm kind of doubting that is your problem. I would keep looking for something else, but wouldn't hurt to replace them anyway I suppose.
I wonder if using a variac to bring voltage up more slowly while monitoring current with a clamp meter would be helpful? That might depend on how the switching power supply starts up, but might get you past the surge and you could at least tell if current draw was normal or not in the steady operating state.
Chip
The 2467 uses the Motorola MC68B02P microprocessor so I assume it uses the Motorola convention for byte ordering. The most significant byte is written at the lowest address followed by the least significant byte at the next address. Does anybody know if this is correct?
Thanks for the tantalum info FireFragon, I'm from the firmware side of things, so my EE skills cause me more problems then they solve.
. . .
You did set a bit of a high standard when you replaced all the 'lytics on the main board, though, and it seems foolish of me not to do the same thing. Did you replace the main board caps with tantalums or did you use new electrolytics?
Thanks for the tantalum info FireFragon, I'm from the firmware side of things, so my EE skills cause me more problems then they solve.
My scope was working, so my goal was to replace all the electrolytic caps before they ruined the boards. I did replace all the electrolytic caps with new electrolytic caps rather than attempting to spec tantalum replacements. From what I could gather, the tantalums require a bit more knowledge of their usage than I possess, so I stuck with the 'lytics.
FireDragon,
When I put my scope back together, I had mounted it backward so the support bracket was pushing on the fan axel preventing it from moving. My 'lab' is kept cool, 60f or so, but the fan turns on immediately; at least it does after mounting it correctly.
I was suckered by the indents on the back side of the fan housing that matched up perfectly with the two little pegs incorporated in the fan mounting plate. They fit together perfectly, they aligned the fan perfectly and there were no such indents on the front side of the fan. Hey, that's the way its got to go right?
C0102 290-0973-00 100uF 20% 25VDC UPW1V101MPD 100uF 35V 20% 105c 0.24
C0107 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0114 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0121 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0130 290-0776-01 22uF 20% 10V UPW1E220MDD 22uF 25V 20% 105c 0.16
C0152 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0185 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0218 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0221 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0307 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0325 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0335 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0512 290-0246-00 3.3uF 10% 15V Axial Tantalum
C0536 290-0246-00 3.3uF 10% 15V Axial Tantalum
C0723 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0731 290-0944-01 220uF 20% 10V UPW1C221MPD 220uF 16V 20% 105c 0.25
C0732 290-0944-01 220uF 20% 10V UPW1C221MPD 220uF 16V 20% 105c 0.25
C0733 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0738 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0740 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
C0957 290-0804-00 10uF +50-20% 25V UPW1V100MDD 10uF 35V 20% 105c 0.16
C0977 290-0246-00 3.3uF 10% 15V Axial Tantalum
Is the fan supposed to blow into the case or out of it? Normally, a fan will blow into the case.
....<snip>.... Hey, that's the way its got to go right?
Is the fan supposed to blow into the case or out of it? Normally, a fan will blow into the case.
[img]https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/?action=dlattach;attach=200673;image[/img]
where the link between the begin img and end img is the link you just copied.Thanks tautech for the instructions on posting photos. But I need more information! I have the forum compatible photos ready to go. Then - if I understand correctly -You've nearly got it.....
1. Place the curser where the photo is to be located on the text page and left click. This pegs the location for the photo.
2. Click on the "Insert Image" icon (located above on the far left side). This displays the "IMG's" where the photo is to be located.
3. Click on "Attachments and other options" (below). This displays the "Attach:" path.
4. Click on "Browse." This displays the "Choose file to up load" page.
5. Locate intended photo on the up load page, then click on the "Open" button (lower right). This displays the photo file info in the "Attach:" path.
If this is correct so far, I got that. But now what? Clicking on "Preview" displays the message text, but no indication of a photo. It appears that something is missing. And if I click on "(Clear Attachments)," nothing happens. I would like to get it right before posting on the blog, but there does not seem to be a way to do that!
Frustrated.
[img]url link to picture on the web or attachement[/img]
At this point the scope was working perfectly, so we started stepping through the functional tests when the readout digits started going crazy. The individual pixels, making up each digit, were modulating in the z axis/intensity. With time they got so bad they would temporarily disappear and they began to affect the trace line.
Photo below shows 3 of the 4 new tantalum caps (yellow) in place.
Still having picture problems. Whenever I load one, it erases the previous one. I've posted countless pictures on various media and blogs and never had this much trouble.
Thanks Bryan for the much appreciated suggestions. Are you saying the grid bias pot may have become intermittent/noisy? This scope is all a learning experience in process.
Brian -
Replacing U2890 appears to have fixed the jittery readouts. I've heard of the Grid Bias adjustments, but am not familiar with it, but will keep that in mind if the readouts act up again.
Regarding pictures; Oh - THAT "More Attachments!" Who would have ever thunk it? Hmmm - well that one passed right through me. Next time I'll have something new to try. thanks!LOL
That would really be nice to find it was as simple as the wrong schematic! But looking again (on my paper work) - it is R2890 and it is next to U2890 B which is located on the schematic at position 6L which is confirmed by the parts list on the same page, as 6L. The schematic I'm looking at is listed as Figure 10-10 in the Manual under LIST OF ILLUSTRATIONS on page iii. But this schematic page is actually located between Fig. 10-10 & 10-11 and has no figure number on it.
As you probably know, when the manual pages are displayed, one can press F4 on the key board to bring up a column of thumbnail pictures down the left side of the monitor screen. You'll have to reduce the size of the schematic page some to acquire the blank space down the left side. These thumbnail page numbers are much easier to navigate through the Manual. In that straight sequential order, this is page 433.
I now have backups of the DS1225Y on another DS1225Y, on my hard drive, on a backup hard drive, on a USB memory stick stored with my manual and on a CD rom. How's that for OCD?
Oh - bad news! My condolences.
A battery voltage down to 1 volt is probably not enough to keep it alive. I'm curious (for the sake of science) did you happen to measure the battery voltage again after the external battery had been disconnected? Based on my battery experience, I'm betting that the nearly expired battery will take on a charge that will last much longer than needed to read the memory, maybe even for days. If that is true than one would not need a makeshift probe on the underside of the DS when reading.
Thanks for sharing.
Baddies.Quite common in X and Y rated caps, they can survive for years in this condition in a dry climate.
All of these probably, hairline cracks on case likely ballooned caps
(http://i.imgur.com/TuZayZo.jpg?1)
Mr. Sauce,
You wrote: "Wouldn't the cal data be kinda useless after repairing the power supply board, it would need a recal anyway?"
I don't know of any reason the calibration would change when rebuilding the power supplies. I counted 9 regulated voltages not counting the CRT HV. But all of those are supposed to be at specified DC levels. These voltages and their tolerances, including allowable ripple, are noted on page 5-3 of the "Tektronix Service Manual" and are available for measurement at J119 on the main board (bottom of scope). Service Manual is available on line. You may already have all this info.
I have not started on my PS boards yet. But beware - there is an error in Service Manual regarding value & location of a couple of the caps. Replacing them with the same ratings as is there now works ok, but removing them all and then using the Service Manual as a guide to install the new ones will be a problem. Previously, and on page 26 MSO explained in more detail, and made a number of entries on replacing these caps. Also, I made a recent entry on replacing the fan including the part # that may be of use for you.
Another tell tale sign is the caps will give off a horrible fishy smell once unsoldered.
Baddies.Quite common in X and Y rated caps, they can survive for years in this condition in a dry climate.
All of these probably, hairline cracks on case likely ballooned caps
(http://i.imgur.com/TuZayZo.jpg?1)
When they finally let go...poof, it's more of an inconvenience than anything else plus the mess they can make. :palm:
Of course and humidity/and or time spent unplugged will allow ingress, then pop.Baddies.Quite common in X and Y rated caps, they can survive for years in this condition in a dry climate.
All of these probably, hairline cracks on case likely ballooned caps
(http://i.imgur.com/TuZayZo.jpg?1)
When they finally let go...poof, it's more of an inconvenience than anything else plus the mess they can make. :palm:
Hmmmm... I was feeling motivated but now a laziness opportunity... replace now or be lazy.... :-//
Most of the others have cracking but are flat on the sides at closer look, this one has a bulge on the side (hard to see in pic), so I think this one maybe ready to go if it's not already gone.
I was wondering about the design of these, the casing is to keep humidity out?
C'mon do the job properly or not at all, they're easy to get, cheap and peace of mind that they've been replaced will help you sleep well. :)
There is a few spreadsheets floating around if you need the drop in replacements for the replacement caps. Here is one that I have and slightly modified to correct for some issues that I encountered with wrong pin spacing on some of the caps.
There are other places where capacity values are critical, like in timing applications. In those cases, the value (uf) should be the same, even if you have to combine cap's to obtain the same value.One could add that timing caps are not normally under the same stresses as PSU, local bulk capacitance or decoupling caps and therefore the need for replacement is uncommon.
You may already know much of this. If not, hope this helps.
Mr. Sauce,
You wrote: "Wouldn't the cal data be kinda useless after repairing the power supply board, it would need a recal anyway?"
I don't know of any reason the calibration would change when rebuilding the power supplies. I counted 9 regulated voltages not counting the CRT HV. But all of those are supposed to be at specified DC levels. These voltages and their tolerances, including allowable ripple, are noted on page 5-3 of the "Tektronix Service Manual" and are available for measurement at J119 on the main board (bottom of scope). Service Manual is available on line. You may already have all this info.
Just for the fun I've also made a few thermal images, enjoy!
If I understand correctly, the temperature with the heat sink in place, and in the case, is about the same as when it is out of the case and an external fan blowing on it.Exactly. Except that it took some time until the case was removed and the picture taken, so it must have been a bit warmer inside the case than on the pictures.
If its not too troublesome, appreciate if you can post photos of your U800 mounted with heatsink, curious how does it look like.Sure, no problem, I can take pictures when I get home.
.....<snip>...
And I have a hard copy of it stored in the scope binder. ...
Do consider Edit or Modify to a previous post so your great info reads correctly in that one post.
Correction - In my previous entry, I wrote -.........
I'll write more later.
Can someone please tell me how to get to the information on 'Switch on off times' and 'Number of Operation Hours'? Thanks!
Can someone please tell me how to get to the information on 'Switch on off times' and 'Number of Operation Hours'? Thanks!
Also even how to change these values what ever you want. (But, seriously, because you need ask this question: Warning, DO NOT enable CAL and play with CAL routines if you do not know exactly what are you doing there! )
Without enabling CAL, just only need use front panel. You need go to EXER 06 routine. It tell this info.
Manuals are for reading!
RF_P -
The total scope hours and the number of power on/off cycles can be found in the scopes memory. To access that place in memory you can follow the procedure in the Service Manual as rf-l indicated, on page 6-10 or the actual page count is 232.
Simple way to get there is -
Hold down the delta V & delta T buttons on the front panel, , then simultaneously press "+ SLOPE." This enters you into the diagnostic mode and you will see "ALL 00" displayed at the bottom of the CRT screen.
Then press "MODE" up, button to cycle from "ALL 00" to "TEST 01." Continue pressing "MODE" up button to cycle down to "EXER 05." Here, you will see that the "ADD" button is illuminated. (Pressing the "MODE" down button reverses the order)
Then press the "COUPLING" up button. This should display your scope's hours and power cycles across the top of the screen.
To exit - press the "COUPLING" down button. This returns you to the DIAGNOSTIC page.
Then press "A/B TRIG" to exit the DIAGNOSTIC page, returning your scope to normal operation.
There are many more options that can be accessed in the diagnostic mode. This is just the straight line path to your requested information.
Let us know your scope numbers. By the look of the dirt accumulated on the fan, it would appear that it has been operated outside of a clean room environment. This can and should all be cleaned up. And the 4 electrolytic capacitors on the A5 board should be replaced ASAP. It appears that the board around those caps in your photo is still in good shape. So, count your blessings. Too often the stuff leaking out of those caps eats up traces and other components in the near vicinity.
My scope indicates over 20,000 hours & 1,100 power cycles.
...Here's the 2445/2465 (plain, not A or B) of the CT and WR service manual if you want it:
And finally. I still have this pesky BU Test F1 Fail 10 on power up. It's a Buffer board EAROM checksum error. As near as I can tell it might only affect the GPIB and the Word Recognizer options. I don't use those options so this error is low priority at this time. While going through the cal routines I noticed the ability to calibrate the Buffer board but no mention of it in the 2465 Options Service Manual. But it IS in the 2465A Options Service Manual. So I performed the calibration and on the first power up cycle the error went away. But then it came back. So this needs more work but after I get the DMM fixed.
...Here's the 2445/2465 (plain, not A or B) of the CT and WR service manual if you want it:
And finally. I still have this pesky BU Test F1 Fail 10 on power up. It's a Buffer board EAROM checksum error. As near as I can tell it might only affect the GPIB and the Word Recognizer options. I don't use those options so this error is low priority at this time. While going through the cal routines I noticed the ability to calibrate the Buffer board but no mention of it in the 2465 Options Service Manual. But it IS in the 2465A Options Service Manual. So I performed the calibration and on the first power up cycle the error went away. But then it came back. So this needs more work but after I get the DMM fixed.
https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg710773/?topicseen#msg710773 (https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg710773/?topicseen#msg710773)
...The 2445/2465 Option 10 GPIB Service Manual (pub #070-4640-00) mentions that "BU CAL F1" has to be performed before the GPIB cal "GP CAL 11".
Thanks. I have all the manuals for the 2465, both the mainframe and the options manual. What is strange is that the calibration routines that appear on CRT give the ability to do a Buffer Board calibration but the 2465 options service manual makes no mention of it. I just happen to have the 2465A options service manual and it does mention it. Either it's an error or most likely I'm missing an update.
The 2445/2465 Option 10 GPIB Service Manual (pub #070-4640-00) mentions that "BU CAL F1" has to be performed before the GPIB cal "GP CAL 11".
But there's no description of exactly what "BU CAL F1" does. What does it do on the 2465A?
OK, I figured out what's going on. The 2465 options service manual I have only covers options 6 and 9. I have a separate 2465 service manual for the DMM (option 1). Do you know of a source for the Option 10 manual?The 2465 service manual is equally uninformative; (irr)relevant page attached.
Hi everybody!
On the road to change as many capacitors as possible in the power supply PCB, I replaced most of the capacitors except C1016 and C1018 those are plastic (0.068uF X2 250VAC) can I replace each with a RIFA PME 271 M (220n X2 275VAC)?
I also have a some (0.1uF 275VAC) but not X2 can I use these to replace the 0.068uF X2? Which would be suitabel the 220n X2 or the 100n?
Hi everybody!
On the road to change as many capacitors as possible in the power supply PCB, I replaced most of the capacitors except C1016 and C1018 those are plastic (0.068uF X2 250VAC) can I replace each with a RIFA PME 271 M (220n X2 275VAC)?
I also have a some (0.1uF 275VAC) but not X2 can I use these to replace the 0.068uF X2? Which would be suitabel the 220n X2 or the 100n?
See attached list.....which I give credit to the Yahoo Tek group. I used the recommended 0.1 uF 275VAC X2 for C1016 and C1018 and they are working fine.
Hi everybody!The absolute value is not as critical as the X2 and voltage ratings that must be maintained.
On the road to change as many capacitors as possible in the power supply PCB, I replaced most of the capacitors except C1016 and C1018 those are plastic (0.068uF X2 250VAC) can I replace each with a RIFA PME 271 M (220n X2 275VAC)?
I also have a some (0.1uF 275VAC) but not X2 can I use these to replace the 0.068uF X2? Which would be suitabel the 220n X2 or the 100n?
When one begins to measure RT, a number of other questions arise. Tektronix specifies it to be measured between the 10% & 90% of amplitude. That’s easy in a perfect world where pulses have square clean corners. But there is the “pre-shoot and overshoot of the leading edge of the displayed pulse. I wrestled for some time with how to deal with that in making the RT measurement. In the article above, they illustrate the answer which I like because it simplifies the measurement.Tek are stating what is the common interpretation of rise time and what we most use.
For information on the EAROMs in the 2445,2465, I opened a thread which may be of interest to the "A" and "B" guys....just search for EAROMEditing your above post and inserting a link would be better. ;)
For information on the EAROMs in the 2445,2465, I opened a thread which may be of interest to the "A" and "B" guys....just search for EAROMEditing your above post and inserting a link would be better. ;)
...Ok, here are some ideas...
I used a function generator with a pot as a voltage divider to get the 0.19V and 1.90V constant. But the maximum output of the function generator is 20.0V p-p so it can't do the 19.0V. I'm in the early stages at looking at possible designs to boost the generator output to about 60V p-p and above. If someone has some ideas I'd like to hear them. I'm not going to try the 190.0V and 500.0V constants because those are insane p-p voltages.
...
Question - How do you know if it's the scope or the Fluke (or both) that are in error?
That is one hell of expensive thermometer :o, considering how valuable this old gem is for that purpose.
But congrats on proofing it that its still performing very good, a temp reading using a scope. >:D
Thanks for sharing. :-+
...I also had an intermittent EAROM, but mine was on the main board. The scope would sometimes power up with a checksum error. I don't recall if it was dependent on how long it was off, but it could have been the same issue since data in the EAROM was being written when front panel settings were changed.
To my simple mind I think this is telling me that the Buffer Board EAROM is defective and after a certain time frame it is dropping data.
In the reading thru the service manual it appears that EXER 02 will read the EAROM data out of both the A5 main board as well as the Buffer Board. Beyond that I'm a little ignorant (and perhaps a little fear of “fail”) as to what I can do with it. I have no experience in dealing with these types of circuits. And I'm not sure if I want to go thru the expense and learning curve to put together an ROM writer and write a new chip. Especially since it appears that this checksum error has no affect on other functions of the scope other than being an annoyance upon power up. So I'm tempted to leave it until it's a total crap out. Which may or may not ever happen. What say the group? Fix it or leave it? I'm open to suggestions.
...
Looking further into the 2465B’s abilities, the scope can also function as a time domain reflectometer. For those unfamiliar with this, the scope’s speed is fast enough to measure the transit time of signals traveling through conductors.
For this test, I connected a BNC T to the scope 50 ohm input at channel 1. A 50 ohm cable connected one port of the T, to the 50 ohm output of the SG503 pulse generator.
...I also had an intermittent EAROM, but mine was on the main board. The scope would sometimes power up with a checksum error. I don't recall if it was dependent on how long it was off, but it could have been the same issue since data in the EAROM was being written when front panel settings were changed.
To my simple mind I think this is telling me that the Buffer Board EAROM is defective and after a certain time frame it is dropping data.
In the reading thru the service manual it appears that EXER 02 will read the EAROM data out of both the A5 main board as well as the Buffer Board. Beyond that I'm a little ignorant (and perhaps a little fear of “fail”) as to what I can do with it. I have no experience in dealing with these types of circuits. And I'm not sure if I want to go thru the expense and learning curve to put together an ROM writer and write a new chip. Especially since it appears that this checksum error has no affect on other functions of the scope other than being an annoyance upon power up. So I'm tempted to leave it until it's a total crap out. Which may or may not ever happen. What say the group? Fix it or leave it? I'm open to suggestions.
...
Properly done the EAROM should have been replaced, but I was able to change the supply voltage slightly and I got it to work without failure:
https://www.eevblog.com/forum/testgear/tektronix-2445-2465-cal-settings-earom-er1400/msg927144/#msg927144 (https://www.eevblog.com/forum/testgear/tektronix-2445-2465-cal-settings-earom-er1400/msg927144/#msg927144)
It may be a long shot, but easy to try. The supply for the buffer board EAROM (signal OEA35) is connected to the one on the main board, so it's the same zener.
EXER02 is harmless. You can use it to make a backup copy of the contents in both EAROMs. Getting the data back in there, however, is another matter. It would have been nice for them to provide a "write" option in the diagnostics.
Mark, first....I want to publicly thank you for the prior assistance you've given me in getting this 2465 fully functional. It is greatly appreciated. :-+You are most welcome! I enjoy working on this old equipment and I'm usually looking for excuses to pop the lid off and get out the service manuals. It's not something I get to do with more modern equipment I use on a daily basis for work.
2nd, I saw your post in the other thread concerning lowering the voltage to the EAROM and I did wonder if perhaps it would help with mine. So I did some checking but I found a discrepancy in what you did vs what is currently in place and perhaps your memory of what you did 20 years ago is a little fuzzy.
I looked up A5 Board VR2003 and it's currently a 7.5 V Zener. You indicated that you lowered the voltage by 2 volts by installing a 9.1 V Zener. Isn't that actually RAISING the voltage by approx 2 volts? But you are correct. That line (OEA35) does supply the EAROM's on the both the A5 Board and the Buffer Board.
On VR2003, note that it and CR2004 are used as a dropper from the +42V rail to supply the EAROM. So, the end result to the EAROM is 42V - 9.1V - 0.7V = 32.2V. The spec on the ER1400 says 35V +/- 8%, so the minimum happens to also be 32.2V.
I just verified the voltage on my EAROM (between pins 1 & 2) as 32.3V. With the original 7.5V zener, this would be higher by 1.6V ( = 33.9V).
To use this GBIP board what am I looking for? I could not find a A20 board in the service manual or in the option manual unless I'm totally blind
TIA
Hello,You need a GPIB board as well, see PDF excerpt
I have a 2467B that I have a GPIB interface for and I'm kind of stuck.
It came with a A20 Buffer Board (i believe the correct name for it). there are connections labeled C/D/E that I can find on the A1 board to connect to but also on the A20 is a 34pin connection that looks like it would go to the A5 Board but there is no 34 Pin connection available on the A5. there is a 40Pin my Serial Number is B053273.
So I take it this A20 Buffer Board is not compatible with my Serial Number.
Heres a few pics of my A1, A5 and A20 boards.
To use this GBIP board what am I looking for? I could not find a A20 board in the service manual or in the option manual unless I'm totally blind
TIA
Hello,Here is the interconnect diagram, it shows that there is no longer a buffer board in the 2467B (serials > 50000)
I have a 2467B that I have a GPIB interface for and I'm kind of stuck.
It came with a A20 Buffer Board (i believe the correct name for it). there are connections labeled C/D/E that I can find on the A1 board to connect to but also on the A20 is a 34pin connection that looks like it would go to the A5 Board but there is no 34 Pin connection available on the A5. there is a 40Pin my Serial Number is B053273.
So I take it this A20 Buffer Board is not compatible with my Serial Number.
Heres a few pics of my A1, A5 and A20 boards.
To use this GBIP board what am I looking for? I could not find a A20 board in the service manual or in the option manual unless I'm totally blind
TIA
Hello,Here is the interconnect diagram, it shows that there is no longer a buffer board in the 2467B (serials > 50000)
I have a 2467B that I have a GPIB interface for and I'm kind of stuck.
It came with a A20 Buffer Board (i believe the correct name for it). there are connections labeled C/D/E that I can find on the A1 board to connect to but also on the A20 is a 34pin connection that looks like it would go to the A5 Board but there is no 34 Pin connection available on the A5. there is a 40Pin my Serial Number is B053273.
So I take it this A20 Buffer Board is not compatible with my Serial Number.
Heres a few pics of my A1, A5 and A20 boards.
To use this GBIP board what am I looking for? I could not find a A20 board in the service manual or in the option manual unless I'm totally blind
TIA
On VR2003, note that it and CR2004 are used as a dropper from the +42V rail to supply the EAROM. So, the end result to the EAROM is 42V - 9.1V - 0.7V = 32.2V. The spec on the ER1400 says 35V +/- 8%, so the minimum happens to also be 32.2V.
I just verified the voltage on my EAROM (between pins 1 & 2) as 32.3V. With the original 7.5V zener, this would be higher by 1.6V ( = 33.9V).
D'OH :palm:. You are absolutely correct. It's a dropper circuit from the +42V supply. I think I have a 9.1V Zener in my pile of parts. If not it will be on my next parts order. Gonna give it try and see what happens. :-+
Could someone tell me if this DS1225Y Nvram-150 can be used? I want to be with everything at hand at the time of exchange of the same.
Quick question while I await the arrival of a 2465B, which I bought for €53/$60 (my first Tek scope - yay), that is supposedly defective. The seller stated that it arced in either the tube or the HV-supply but was otherwise in perfect working condition and in calibration until that day. I know that it is kinda hard to speculate on without more information, and he did mention that a new tube might be needed which seems plausible, but any ideas what might be the source of this arcing?
The seller stated that it arced in either the tube or the HV-supply but was otherwise in perfect working condition and in calibration until that day. I know that it is kinda hard to speculate on without more information, and he did mention that a new tube might be needed which seems plausible, but any ideas what might be the source of this arcing?
The seller stated that it arced in either the tube or the HV-supply but was otherwise in perfect working condition and in calibration until that day. I know that it is kinda hard to speculate on without more information, and he did mention that a new tube might be needed which seems plausible, but any ideas what might be the source of this arcing?
The AC line safety capacitors may have failed which is a common and easily repairable problem.
The seller stated that it arced in either the tube or the HV-supply but was otherwise in perfect working condition and in calibration until that day. I know that it is kinda hard to speculate on without more information, and he did mention that a new tube might be needed which seems plausible, but any ideas what might be the source of this arcing?
The AC line safety capacitors may have failed which is a common and easily repairable problem.
Yes, but some of those capacitors are "hidden"; in the last week I've "done" a 2465 and 2445B, and while the "hidden" caps hadn't failed, they were crazed. FFI, see http://www.condoraudio.com/wp-content/uploads/Projects/Tektronix-2465B-Oscilloscope-Restoration-Repair.pdf (http://www.condoraudio.com/wp-content/uploads/Projects/Tektronix-2465B-Oscilloscope-Restoration-Repair.pdf)
And don't forget the infamous control board caps, q.v.
The HV supply arcing may simply be neons flashing.
The seller stated that it arced in either the tube or the HV-supply but was otherwise in perfect working condition and in calibration until that day. I know that it is kinda hard to speculate on without more information, and he did mention that a new tube might be needed which seems plausible, but any ideas what might be the source of this arcing?
The AC line safety capacitors may have failed which is a common and easily repairable problem.
Yes, but some of those capacitors are "hidden"; in the last week I've "done" a 2465 and 2445B, and while the "hidden" caps hadn't failed, they were crazed. FFI, see http://www.condoraudio.com/wp-content/uploads/Projects/Tektronix-2465B-Oscilloscope-Restoration-Repair.pdf (http://www.condoraudio.com/wp-content/uploads/Projects/Tektronix-2465B-Oscilloscope-Restoration-Repair.pdf)
And don't forget the infamous control board caps, q.v.
The HV supply arcing may simply be neons flashing.
Those paper capacitors all seem to be universally bad having either physically degraded do to age like you describe or shorted out. I think they have been changed in my 2445B but I have a few junked 22xx main boards where they are crazed and I do not bother pulling them for spares.
The reason I suggested them is that they do not always go out with a bang and their arcing may have been mistaken for a high voltage problem while not disabling the oscilloscope. They are just something else to check.
I do not know of any reason they cannot be replaced with modern film or ceramic safety capacitors and of course they can always be derated.
The chances of the CRT being the source of the HV issue is rather remote, unless it's been subject to damage or shock. The best way to find the source of the arcing is to remove the case, darkened room, and look for the source. But keep your hands behind your back. :P
The AC line safety capacitors may have failed which is a common and easily repairable problem.
The HV supply arcing may simply be neons flashing.
The chances of the CRT being the source of the HV issue is rather remote, unless it's been subject to damage or shock. The best way to find the source of the arcing is to remove the case, darkened room, and look for the source. But keep your hands behind your back. :P
According to the seller he just powered it up and somehow experienced arcing, that is all I know for the moment, so I don't think it was damage or shock. A good idea I hadn't thought of with the darkened room, and good advice too. :)The AC line safety capacitors may have failed which is a common and easily repairable problem.
That was my first thought too but I shuck it off as wishful thinking so I am glad that you suggest this. Those will be the first I examine after having looked for anything obvious.The HV supply arcing may simply be neons flashing.
Flashing as in worn out? As far as I know the scope does not work anymore, could these cause that if they are broken and/or kill other components.
Flashing as in worn out? As far as I know the scope does not work anymore, could these cause that if they are broken and/or kill other components.
They prevent the cathode-grid voltage from becoming dangerous. Normally that only happens after the power is turned off. Some Tek scopes also have a neon in the main PSU that flashes continually, but IIRC the 2465 doesn't.
Well, there's your problem.. And, sometimes you win, sometimes you lose.
How are my chances that nothing else is damaged from this broken tube? Everything else looks totally undamaged and in excellent condition. After all, it has been turned on with the tube in this state.
Tubes from 2445, 2445A, 2445B, 2465, 2465A, 2465B,2430, 2430A, 2432, 2432A and 2440 are all suitable, right?
But it is neat to see Tek's innovative and at the time leading edge process that combined a ceramic bell of the CRT with the glass gun and faceplate. As far as I know no else attempted that. But I did read somewhere that Tek shared some of their CRT technology with Sony which directly influenced the design of the Trinitron CRT.
... the gun and metal parts inside looks artistic, at least to my eyes.
Been there, done that, ended up with: https://entertaininghacks.wordpress.com/2016/03/09/rescuing-a-broken-tektronix-465-crt/ (https://entertaininghacks.wordpress.com/2016/03/09/rescuing-a-broken-tektronix-465-crt/)
PS : The broken tube, have you dump it yet ? I really love to own it if you're going to toast it, as the gun and metal parts inside looks artistic, at least to my eyes. I will pay for the shipping cost.
This is my first time replacing a CRT but I'm guessing that I will likely have to do some or all of the adjustments outlined in the "CRT Adjustments"-section of the SM, right?
Edit: this is the old tube, disregard the light specs and what looks like (and is) a brush stroke. That Lichtenberg-looking burn, does that perhaps indicate that the tube was powered when it had its catastrophic failure?
Now, the machine has the following problems- It shows Fail Test 05 -44. Presumeably, the DAC312 and the Comparator 311 on A5 has something wrong.
I'm not sure how to proceed with the adjustments but will study the relevant parts of the SM and try to figure out what exactly needs to be done and what my options are, given the equipment I have and my limited budget.
The 2nd and 4th channel (I think) did show a bit of noise when the scope was cold but that went away after warming up.
The readout and traces shimmers a tiny bit randomly from time to time. Otherwise everything appears to work fine but I haven't yet done much testing.
The seller obviously didn't really know what he was selling since his reply to me asking for probes was "please explain what probes are and where I can find them". :PUse word "cables". ;D "Cable" is more explaining that "probe".
I got similar deals on a Tektronix 2440 and 7854 which apparently sat in storage for many years and were in excellent condition. Later I hunted down a front cover for the 2440 so it remains clean and protected.I was thinking electrolytic caps warming up too so great that you mention this. And this one unfortunately does have leaky surface mount caps but it still haven't caused that much damage.The 2nd and 4th channel (I think) did show a bit of noise when the scope was cold but that went away after warming up.
Warming up usually results in better performance from aluminum electrolytic capacitors so this might indicate that they are at the end of their useful life.
I am fussy on exactly which 2465 series oscilloscopes had problems with leaky surface mount aluminum electrolytic capacitors but I do not think the early and late ones did but it is still worth checking.QuoteThe readout and traces shimmers a tiny bit randomly from time to time. Otherwise everything appears to work fine but I haven't yet done much testing.
Check to see if this is just an artifact of the beam multiplexing needed to display the readout by disabling the readout. Sometimes the readout will momentarily synchronize with the sweep to produce visible artifacts.
Cables might have made more sense to him but I would expect him to answer that there is a power cord included.. :D I don't know about the probes being more valuable than the instrument but it sure was a nice bonus having a working 2465B thrown in when purchasing probes. I'm thinking of selling it once refurbed and perhaps use the money to finally buy a modern scope. I've been wanting a Rigol 1054Z for a while.The seller obviously didn't really know what he was selling since his reply to me asking for probes was "please explain what probes are and where I can find them". :PUse word "cables". ;D "Cable" is more explaining that "probe".
Quite funny in situations where "cables" are more valuable than the instrument itself.
Taking a scope break –
@ cheeseit and Old-E
There's some good restoration tips in this sticky thread including polishing BNC's.
https://www.eevblog.com/forum/repair/vintageclassic-renovation-techniques/ (https://www.eevblog.com/forum/repair/vintageclassic-renovation-techniques/)
why does this thread have some many views/replies for some random scope ?
My scope arrived very clean inside and out, except for the BNC's that are tarnished. like yours, they all work just fine, but some cleaning would help the appearance. You said you used Silvo to clean the BNC's. Is that a silver polishing compound?
Interesting that you used hydrogen peroxide on the knobs which might brighten mine up too. Never heard of using it for that.
Also have been wanting to suggest that you replace the 4 electrolytic caps on the A5 board ASAP, because they leak, as yours are just starting too. C 2965 appears to be corroding the adjacent screw head. Mine was worse and an adjacent IC, U2890, had absorbed the acid which caused it to fail. Thought those IC's were totally sealed, but this one had a corroded interior when I opened it up, along with signs of corrosio