Author Topic: Tektronix 2465B oscilloscope teardown  (Read 455213 times)

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Offline Howardlong

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Offline timb

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Re: Tektronix 2465B oscilloscope teardown
« Reply #526 on: October 17, 2015, 07:35:12 am »
Well, there you go! Thanks! This thread has been going awhile and I've read the whole thing, must have just glossed over that at the time.

So, I reassembled the scope, turned it on and...it worked...sort of. The readout and trace is super crisp, all supply rails are tight, but the fan doesn't work anymore! After a bit of poking around I noticed the fan wire that goes from the PS to the feed through cap had come unsoldered. (Which I didn't notice since I'd put heat shrink over the connection.)

I fixed it, however I don't think it was the problem. The fan still doesn't work. I guess I've got to take the power supply apart again. *Sighs*

I figure it has to be the LM317 as I'm not getting any voltage on the fan wire. Unless there's something wrong with the solder connection between the wire and the board or the wire itself. You know, looking at the schematic again, maybe the wire is the issue. There's a 300 ohm resistor between +15V and the fan wire, so even if the LM317 was bad, I should be seeing *some* voltage there.


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Offline timb

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Tektronix 2465B oscilloscope teardown
« Reply #527 on: October 18, 2015, 06:51:20 am »
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*



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« Last Edit: October 18, 2015, 06:53:25 am by timb »
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Online med6753

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Re: Tektronix 2465B oscilloscope teardown
« Reply #528 on: October 18, 2015, 02:39:54 pm »
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*



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This is exactly why I am so lucky (Knock on wood) that the supply voltages on my 2465 DMS are (so far) in spec. You're not the first I've seen pull the supply and invertor boards and have the damn thing FUBAR upon reassembly. Those boards are apparently a PITA to get out on a typical 2465 without options. Mine has a DMM and C/T plus buffer board which makes it even more of a challenge. I feel for you. Hopefully you'll find the issue.   
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Online MarkL

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Re: Tektronix 2465B oscilloscope teardown
« Reply #529 on: October 18, 2015, 02:56:40 pm »
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.
 

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Tektronix 2465B oscilloscope teardown
« Reply #530 on: October 18, 2015, 08:41:44 pm »
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.

I couldn't remember the exact number, but yes 10uS is what it should be.

So, I read a thread on here where someone is having the same problem after a recap. His issue was a dead opto-isolator. I'm going to check mine tonight, but last night I tried varying the 10Vref pot; the voltage responded, as did all the rails *except* +5VD, which tells me it could be U1040. (Since the other rails are actively regulated.)

That 300mV sawtooth on 5VD could be the input to error amp U2 oscillating if U1040 isn't working, right?

Does anyone know what the substitute is for U1040? It's marked SOC123A in the schematic.

Edit: Parts list shows H11AX, which gives me 4N2X as well. I get the same when I search for SOC123A.  Seems like they're a family. Hmm, still in production too!


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« Last Edit: October 18, 2015, 08:55:50 pm by timb »
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Online MarkL

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Re: Tektronix 2465B oscilloscope teardown
« Reply #531 on: October 19, 2015, 01:28:22 am »
I wouldn't blame U1040 just yet.  The frequency of the sawtooth might provide a clue.  Is it the switching frequency or something else?

Is the fan running now that you fixed the broken wire?

If things were working before you fixed the fan, go back a step.  Try disconnecting the fan or undo whatever you did, no matter how unrelated it may appear.

Can we get a screen shot of the ripple on +5VD?  Any ripple on the 10V ref?  How's the +15V unreg, which feeds the +10V ref circuit (and also the fan)?

 

Offline timb

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Tektronix 2465B oscilloscope teardown
« Reply #532 on: October 19, 2015, 07:45:58 am »
Okay, I built a load and hooked it to the supply. I checked +-15V and both +5V rails, everything is in check. Less than 20mV ripple on the +5VD rail. I tested -5V and -8V, looks like they are sitting very low: -8V rail is sitting at -1.2V, -5V is sitting at -2.7V, but maybe I need to up the load resistors, because those rails were fine inside the scope last night, I think. I used 50 ohm on -8V, -5V and +5V; 100 ohm on +15V and -15V; 150 ohm on +42V; 2k on +87V; 2 ohm on +5VD.

To answer your question, I did try disconnecting the fan. One of the first things I tried!

Tonight I'll get a screen cap of the ripple on the 5VD rail.


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« Last Edit: October 19, 2015, 09:37:58 pm by timb »
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Re: Tektronix 2465B oscilloscope teardown
« Reply #533 on: October 19, 2015, 09:41:57 pm »
So, I'm about to start more testing, but I was reading the service manual earlier. Looks like the -5V rail relies on -8V, so one of them could be the problem. I'll check them inside the scope first.

The other thing I was thinking, what if the line up signal isn't getting through? That could hold the system in reset. Anyway, first thing's first, put the supply back in the scope and check the ripple again.


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Tektronix 2465B oscilloscope teardown
« Reply #534 on: October 20, 2015, 07:00:30 am »
Alright, so I changed all the 50 ohm resistors out with 100 ohm ones on my dummy load. Hooked it up and the supply was 100% in regulation. Put it back in the scope and it started right up. All rails are in spec and there's no visible ripple on +5VD (at least at 50mv/div).

This thing is gaslighting me!

Nearest I can figure is maybe one of cables that goes from A1 to the supply wasn't secure, though I swore I checked those.

I'll check deeper tonight, measure the ripple on all the rails. But yeah, there you go. Weird.

Edit: Oh, here's the load I made. Pretty simple and in the end worked great!






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« Last Edit: October 20, 2015, 01:23:17 pm by timb »
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Re: Tektronix 2465B oscilloscope teardown
« Reply #535 on: November 07, 2015, 06:10:21 pm »
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.
         

For about $45 USD in assorted parts I was able to get most of the DMM option calibrated....

DCV: the calibration constants required are 0.19V, 1.90V, 19.00V, 190.0V, and 500V. I used an LM723 to generate a precise 19.00V and then cobbled together a voltage divider to set 0.19V and 1.90V. For 190.0V I used this little device:

http://www.amazon.com/gp/product/B010UGJF1I?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00

There were concerns that this inverter would be very unstable and hard to set precisely at 190.0V but surprisingly it was very stable. The processor in the DMM accepted all the constants fed to it and the DCV function is now calibrated and accurate up to at least 190V. I haven't figured out a way to get an accurate 500V so that range wasn't calibrated but for now I'm very pleased with the results.

Hi-Ohms and Lo-Ohms. I ordered .1% resistors from Mouser and these ranges calibrated quickly with no issues.

I did some spot checking of ACV and it looks reasonably accurate as is. I have the required constants to perform a full calibration but it does require a precise calibrator. ACV requires the same voltages as the DCV but some at frequencies other than 60 HZ. No easy way to achieve that. The DCA and DCA were also left as is. Again that requires very accurate standards. I have other DMM's to measure ACV and current if needed. 

This 2465 is now about 98% done and will serve as my “swiss army knife” with it's combination scope, frequency counter, and DMM. It still has an EAROM checksum error in the buffer board upon power up that I haven't quite figured out but it doesn't appear that it affects anything once bypassed. So for now I'm leaving it as is.
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Offline FireDragon

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Re: Tektronix 2465B oscilloscope teardown
« Reply #536 on: December 22, 2015, 06:09:13 pm »
I just got a 2465BCT for Xmas! However, it needs to be fixed up. I fired it up and started running it through its paces. It appeared to be working ok. I had two 100Mhz probes in x10 mode connected to the calibration output running at around 6Mhz. When I switched them to x1, the vertical trace went large (as expected) then I heard a "pop" and the scope went dead after a few seconds. I opened it up and found that C1016 on the A21 board had exploded and that R1015 was seriously burned. The main fuse had popped as well.

C1016 and R1015 form an RC bridge across hot / neutral just before the CR1011 bridge. Some sort of surge must have been coupled from the high voltage side when the CRT vertical voltage jumped which took out C1016. That probably short circuited and took out R1015 and, in turn, the fuse. The question is how that coupling could have happened? I don't currently have a clue.

The maximum voltage on the calibration output is 0.4V, so there is nothing that I should be able to do with the probes that would cause a scope failure! I am sure that there is an underlying cause, but I don't know what it might be. Perhaps someone will have a suggestion.

I could not find any other damage and the boards all look very good in general. The scope actually ran for a few seconds after I heard the "pop" so hopefully the new damage is limited to C1016 and R1015. This is a B010xxx scope so it is an early BCT. There are no SMT parts at all which is wonderful. No Dallas chip to deal with either.

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.

So far, I have only done a partial tear down to find the immediate problem and to visually inspect (most of) the scope. Since all of the tear downs I have seen have been for 2465, 2465A and later model 2465B scopes with SMD parts, I will post pictures when I do a full tear down. I will also post the parts that I am using. So far that is

   C6190 - C412C223K1R5TA Kemet 0.022uF MLCC, 100V, 10%
   C1016 - ECQ-U2A683ML Panasonic 0.068uF Film, 250VAC
   R1015 - 291-36K-RC  Xicon, 36K 5% carbon film

I don't have the relevant schematics for the option 1E modification, so all I have is the value for C6190 but not the voltage rating or suggested type. Other caps in the area are 25V, 50V or 100V so I am going ceramic with 100V.

The project may move a bit slowly given the need to order (and wait for) parts and the time of year. There will probably be several cycles of that as I discover more parts that need to be replaced. I also don't want to pull some of the more difficult boards more than once, so when I have one of them out I will do everything possible before putting it back in. That could cause additional order / wait cycles.

In the meantime, I look forward to any and all suggestions that more experienced people may have. This is my first major scope tear down and refurbishing (although I did repair a 60's vintage scope in the very early '80s - threw it out about 15 years ago, shouldn't have done that). Worse, I have had to interrupt a tear down and rebuild of a Revox B215 to do this one!

So - wish me luck and let me know anything that might help!
 

Offline FireDragon

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Re: Tektronix 2465B oscilloscope teardown
« Reply #537 on: December 25, 2015, 11:34:18 am »
I have created my parts list (attached). There may be a few errors because the service manual does not distinguish between radial vs axial, aluminum electrolytic vs. tantalum electrolytic (expect for one part) or polar vs. bi-polar. It also lists a single part as "ALUM" which I have interpreted as aluminum electrolytic, but perhaps it means bi-polar. I have taken my best guess by looking at the scope as much as possible and by reading other people's posts. I will update the list, as necessary, when I can compare individual items directly to the circuit boards. This is also a very early 2565B CT (serial number B010xxx). The actual board versions aren't in the service manual (some are -02 and the manual has -00 and -05 as the closest).

However, except for complete board differences (SMT vs. through-hole and the high voltage board) there do not appear to be any version differences that affect this list. I have ordered everything on the list except for the LTC-7PN battery (which is the exact part currently in the scope, so it is possible that has already been changed). I did include the fan board although that is probably not in the scope (just a single capacitor, so no big deal).

On additional consideration and taking into account other people's repairs, I am currently thinking that when I switched from x10 to x1 and the vertical size jumped that there was a minor current surge to handle the increased vertical deflection. The C1016 capacitor was probably very marginal and blew, shorting out. That would have stressed R1016, burning it due to excessive current (which would have then been directly across the main power supply at 132V) finally causing the main fuse to burn out. I have also discovered that C1018 - which is exactly the same type and value of part - is cracked. Since those two capacitors apparently tend to fail that may (with luck!) be the extent of the problem.

On the good news side, when I reported the situation to the vendor and said that I was planning on keeping the scope anyway, unasked the vendor refunded $50 of the purchase price. That has paid for most of the materials for a complete rebuild!
 

Online med6753

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Re: Tektronix 2465B oscilloscope teardown
« Reply #538 on: December 25, 2015, 02:58:02 pm »

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 EAROM 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  :-+     
« Last Edit: December 26, 2015, 02:21:03 pm by med6753 »
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Offline Gixy

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Re: Tektronix 2465B oscilloscope teardown
« Reply #539 on: December 25, 2015, 07:12:02 pm »
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.
 

Offline FireDragon

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Re: Tektronix 2465B oscilloscope teardown
« Reply #540 on: December 26, 2015, 08:54:23 am »

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  :-+   

Thanks. This is a BCT which does not have the DMM, but does have the frequency counter. When choosing this unit, I had several priorities...

1. 2465B / 2457B - but preferably 2465B because the CRT is more easily replaced and is larger. I don't really need the CRT features of the 2467B. I wanted a 2465B because while it is far more than I need at the moment, but I can only afford to do this once so I want the most bang that I can get.

2. I wanted a unit without SMDs. Easier to maintain and appears to have a lot fewer service "updates" apparently due to Tektronix still trying to fine tune the SMD version. Also, no Dallas chip to deal with. Once the procedure is known, changing a battery is not a big deal.

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.

4. I already have a DMM of about the same accuracy as that provided by option 01. That accuracy is not much to write home about and increases the size of the scope. So while a BDM or BDV is ok, optimal is the BCT.

With this unit I hit all of my points exactly. It is an early model (s/n B010xxx), but there are no service updates listed for any s/n below B050000. There are some board variations, but those appear to more layout than anything else. So, while I paid more for it than I might have for a plain 2465B in the same shape, I think the cost difference was worthwhile. Certainly cheaper than buying a separate frequency counter. When it failed, the $50 rebate from the vendor paid for most of the parts which reduced the cost further (since I would have recapped it anyway - just not as soon).

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.

The case and back were not the cleanest and had permanent marker, floor scum and sticker goo all over them. I have cleaned all of that of so the case looks nice now. I haven't had the front of the scope off yet, so it is still a bit grungy.

I may also need help identifying some parts. My part list was as accurate as I could make it, but I am sure that there will minor corrections (radial vs. axial / aluminum electrolytic vs. tantalum electrolytic / polar vs. bi-polar, etc.) which are not spelled out in the service manual. Also, I don't have the 24x5B / 2567B options service manual. I have been unable to find it online and am not willing to pay for what should be a free manual unless it is absolutely necessary. My understanding is that Tektronix made all of that information publically available.

Right now I am waiting on Mouser. The parts shipped on the 24th so they will probably sometime early next week.
 

Offline FireDragon

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Re: Tektronix 2465B oscilloscope teardown
« Reply #541 on: December 26, 2015, 09:04:59 am »
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.

Thanks. That looks like an easy procedure - especially with the AAA battery case. It might be good to have a replacement for the capacitor on hand in case it gets damaged by removal. That will probably be the last thing I do. Having seen some other pictures of the battery, I suspect that it has been changed comparatively recently. Mine has the bright yellow label and is not the apparently older blackish version without a label. Also, the part number of mine exactly matches Mouser's part number.

I am trying to join the Yahoo Tekscopes group and the arc / arc2 groups as well. However, I refuse to get a Yahoo account - I keep fairly tight security policies and Yahoo doesn't need to know my phone number OR date of birth! The moderator may not accept an email subscription request so that avenue of knowledge may be blocked off (don't have a Google account either and only have a Microsoft account for downloading development tools). Otherwise, I have read everything else I have been able to find. This thread and the 1E thread (also on this board) have been very informative. I have read this thread once and will read it again while I am waiting.
 

Online med6753

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Re: Tektronix 2465B oscilloscope teardown
« Reply #542 on: December 26, 2015, 02:01:34 pm »


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.

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.


Quote
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.

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. 
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Offline FireDragon

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Re: Tektronix 2465B oscilloscope teardown
« Reply #543 on: December 26, 2015, 04:34:34 pm »

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.

For my near-term needs, 150Mhz is fine. Even a 60Mhz scope would have done. However, I only plan on buying an analog scope once and so I went with much more than I actually require at this time. That could change rapidly, so the 2465BCT is the best that I can do at this time.

I have the following PDF manuals...

   Tektronix 2465 Options 06 09 CTT WR Service
   Tektronix 2465A Options Service Manual
   Tektronix 2465B 070-6863-00 Service Manual
   Tektronix 2465B 070-6863-01 Service Manual
   Tektronix 2465B Operators Manual

I would like to find a PDF copy of the 24x5B / 22467B Options Service Manual. I think that the 2465A Options Service Manual will be pretty close. I don't think that there was much changed for the options. It has the GPIB, TV, CTT and DMM options in it.




 

Offline timb

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Re: Tektronix 2465B oscilloscope teardown
« Reply #544 on: December 27, 2015, 10:15:07 pm »
It's good to 200MHz, not 150MHz.
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Online med6753

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Re: Tektronix 2465B oscilloscope teardown
« Reply #545 on: December 28, 2015, 01:37:15 am »
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.
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Offline FireDragon

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Re: Tektronix 2465B oscilloscope teardown
« Reply #546 on: December 28, 2015, 05:36:05 am »
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 have a 2465B CT, so mine is probably good to 200Mhz. I don't actually have anything that describes that for a 2465B.
 

Offline FireDragon

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Re: Tektronix 2465B oscilloscope teardown
« Reply #547 on: December 28, 2015, 09:05:40 pm »
The parts for refurbishing my 2465B CT have arrived!

Here are the first batch of pictures. These are all of the outside. The next batch will be the inside after I open it up.

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.

Front of scope.
 

Offline FireDragon

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Re: Tektronix 2465B oscilloscope teardown
« Reply #548 on: December 28, 2015, 09:06:44 pm »
2465B CT Outside pictures continued...

Back of scope.
 

Offline FireDragon

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Re: Tektronix 2465B oscilloscope teardown
« Reply #549 on: December 28, 2015, 09:53:06 pm »
2465B CT Outside pictures continued...

Left side of scope.
 


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