Author Topic: Tektronix 2465B oscilloscope teardown  (Read 455282 times)

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Offline Old-E

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Re: Tektronix 2465B oscilloscope teardown
« Reply #650 on: February 20, 2016, 04:53:04 am »
More on the Dallas IC up-grade.
I powered up the 2465B again today and all appears well, so the FM16W08 appears to be holding its memory.   But, just in case, I ordered a spare DS1225AD today to copy the scopes cal data to and then put it in storage, just in case.   I have a spare FM16W08 and adapter board that I'll do the same with.   AT this point, it's cheap & easy backup.   Then if we get hit with an EMP or a super solar storm, maybe one will survive, assuming the rest of the scope makes it.

DSO - I think there may be some confusion about the data retention of the FM16W08.   See data below.   The 10 years at 85 Deg. C is hot.   At 65 Deg. C (that's 149 F) the data retention is 151 years - according to the Cypress data sheet.   So, if I keep it below 75 F, it might even out live us.



There was a concern of shorting the pins on the Dallas DS1225Y when removing it.   But after looking at the expanded diagram of that IC posted by Holden, I concluded that if they were momentarily shorted, it would be through high impedance paths.   So the battery should survive that.   And I used the smallest tip on the vacuum desolder tool, so I don't think they ever shorted.

After removing the DS1225Y, I was about to plug it into a conductive piece of black foam, but then had second thoughts about it discharging the battery through possible high impedance paths via. the foam.   But, then while looking up DSO's concern about the IC's life, I found where the data sheet seems to think it's not a problem - if I understand it correctly.  So, you're probably right - not a problem.

Also, for the sake of science, I want to excavate through the top of the old IC to the battery, to measure the remaining voltage.   If done right, the IC will not be functionally harmed.

DSO - When using my vacuum desolder tool, most of the pins desoldered ok.   But half dozen or so pins were a challenge.   It just would not pull all the solder out.   Even turned the board upside down to get help from gravity.   Cleaned the tip orifice, but it was clear and the vacuum was working at the tip.   Since this is my first real application with it, I wanted to ask what temp you had yours set to?   This one was set to 300 C.   Another possibility was, the tip might be too small to transfer enough heat through the multi-layer board.

Below are photos of the board before and after replacing the Dallas memory IC.
 

Offline Old-E

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Re: Tektronix 2465B oscilloscope teardown
« Reply #651 on: February 20, 2016, 05:01:46 am »
Well, the pictures were lost again.   This is the most unfriendly picture loader.   No way to see in advance what is ready to be posted.   Will try to get 3 of them back here.
 

Offline MSO

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Re: Tektronix 2465B oscilloscope teardown
« Reply #652 on: February 22, 2016, 07:18:24 am »
OLD-E,

On the DS1225Y, the battery is located near the bottom of the chip, not the top (at least that's what I gleaned from Holden's write up).  Holden goes on to recommend evacuating pin 7 on the embedded DS1218 memory controller if you need direct access to the battery's positive node.

When sucking solder with a Hakko or any other desoldering gun, it's common to have some pin/hole combinations not fully evacuate. The normal course of action is to resolder those pins and then try again. The fresh solder aids the heat transfer from the gun through the pin/hole and usually results in complete evacuation of the solder.

It's recommended that when using a desoldering gun to get the pin into the orifice of the gun and apply side pressure on the pin to aid heat transfer. I also try to get the gun to the solder filet itself, but not far enough to actually touch the solder pad. When I see the solder melt, then I apply the vacuum and that usually clears the solder. Some of the pins have been bent over to hold the chip in place during the manufacturing process, so those pins require a two step process; just touch the solder filet with the gun and suck up as much solder as will easily come. Then straighten the pin, apply new solder if needed and then follow the normal sequence.

Finally, you will encounter situations where the soldered pad has little thermal relief; the pad is part of a large trace or ground plane that dissipates the heat from the desoldering gun, making it difficult to get an easy flow of solder.  In these situations, you may need to raise the temperature of your desoldering gun to get enough heat to get the solder to flow easily.

Having said all that, I set Hakko 808 to 350 C when desoldering. That high of a temperature requires a lot of care not to lift a pad.  While it's good to touch the pin and the top of the solder filet, you really don't want to touch the pad itself and you don't want to apply the heat for too long.  If the joint doesn't fully desolder, move on the next joint and come back to the failed one later.  Apply new solder to the failed joints and then try those again.

There may be a joint or two (I didn't encounter any when re-capping the 2467B) that simply won't submit to the desoldering gun. With those, you'll either have to heat with an iron while simultaneously lifting the component or, in the worst case, cut the pin off on the component side of the board and then use solder wick to clear the hole.

Almost forgot; I used a desoldering tip with a 1.0mm hole for all of the components on the 2467B.  The two large 290uf caps C1021 & C1022 on the A3 board had the largest diameter leads and pushed my 1.0 mm tip to its limits, but with a little solder wick to remove the excess solder on the top of board, I was able to use the gun to clear those whales properly.

As an aside, I checked all the caps that I pulled out of my 2467B and found only the RIFA caps (those rectangular caps with translucent plastic cases) were out of spec.  All the aluminum electrolytics, even those that had started leaking, were still measuring OK, so it looks as though I caught them all in time.

It's good to hear that you were able to save your calibration data; I know I sighed a huge sigh of relief when I was able to read mine with my programmer.  I was paranoid enough, though, to read the bin file and double check that all the calibrations I had recorded via EXER 02 before starting work on the scope matched those in the bin file. 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?

 
 

Online BravoV

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Re: Tektronix 2465B oscilloscope teardown
« Reply #653 on: February 23, 2016, 03:44:08 am »
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?

Not bad for the OCD :-DD, but you forgot putting it into cloud storage, and another usb stick stuck with duct tape inside the scope.  >:D
« Last Edit: February 23, 2016, 04:33:13 am by BravoV »
 

Offline MSO

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Re: Tektronix 2465B oscilloscope teardown
« Reply #654 on: February 23, 2016, 04:18:44 am »
I'll get there Bravo, I'm just getting warmed up.

BTW, thanks for all your contributions to this thread. I don't think I would have been successful without the myriad pictures, tips, observations and comments that you and many others have made here.
 

Online BravoV

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Re: Tektronix 2465B oscilloscope teardown
« Reply #655 on: February 23, 2016, 05:08:45 am »
MSO, my pleasure and thanks to other contributors too that made up this thread.  :-+

PS : Actually I created this thread just to share this beast teardown photos at 1st, never thought it grows into this giant.  :o

Offline FireDragon

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2465BCT Repair and Modifications
« Reply #656 on: February 23, 2016, 08:26:42 am »
I got the latest set of parts in and made the latest round of repairs and modifications.

I replaced the feed through fan capacitor (which was shorted) and the fan with a higher capacity fan with about the same noise level. I also added an 0.1uF ceramic bypass capacitor to help suppress noise on the fan input voltage to prevent it from feeding back into the scope. That should reduce the overall temperature inside the scope because the default will be higher airflow.

Additionally, I was unhappy with the noise level on the various power supply voltages. All of them were well within specification, but the noise was still much higher than I liked. So, on board A2A1 I replaced the 100uF filtering capacitors - C1260, C1280, C1300, C1330, C1350 - with 150uF capacitors. Additionally, I added a 150uF capacitor across VR1293. The reason for this, is that all of the output voltages have some sort of filtering across them - except for the 10V reference voltage. Its noise specifications are very loose, and any noise on it will be copied by all of the other output voltages because they will attempt to match the reference voltage, noise and all.

I also added a 50 ohm resistor between ground and the Option 1E input signal to provide proper termination.

Finally, I replaced the 10.000Mhz crystal with a 10.0000Mhz crystal. To support that I changed C2550 and C2551, respectively to 33pF and 39pF (this was actually no change for C2550, but I replaced it anyway). This gives me 10.00014Mhz whereas before it had been somewhere around 9.99280Mhz. I am measuring the frequency with the scope itself and I have reason to believe that it is reading high - but by how much I don't know yet since the scope isn't calibrated yet and I don't have a calibrated frequency reference. Changing the crystal won't improve the scope's performance or accuracy, but it should bring the resulting calibration constants closer to "zero" and so less likely to hit an extreme point. I couldn't easily get the frequency close to 10Mhz. When I had C2551 at 33uF I had 10.00047Mhz, and 39uF gives me 10.00014. The next step up would be 43uF which would probably be too much - especially if the scope is reading the frequency high.

The result of the power supply changes is a drastic reduction in noise on the all of the output voltages.  I probably should have replaced C1220 and C1240 but I didn't have any higher voltage, high capacity capacitors on hand. Still, most of the output voltages now have total noise at around 1-2mv with no observable line noise. One of the  +5v supplies (J119-2) has about 20mv noise which may be line related, but up to 30mv line related noise is allowed and up to 150mv total noise. So, a definite win!

I'm getting pretty good at taking this scope apart and putting it back together with all of the practice I'm getting!

 

Offline Old-E

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Re: Tektronix 2465B oscilloscope teardown
« Reply #657 on: February 25, 2016, 06:21:23 am »
LOL - - Following the stress, and then the joy, of getting the cal data out of the old DS1225Y, I understand the desire to have back up memories for the backups, etc.  So it might be said; the more intense the emotional experience, the more memory backups.

My new DS1225AD arrived today, so I can program it along with a spare FM16W08.   Then I'll have 3 back ups (counting the hard drive) in addition to the new FM IC installed in the scope.

In addition to all that, I still have the old DS1225Y removed from the scope.   I excavated through the epoxy of its underside this evening to get to pin 7 on the DS1218 as MSO suggested.   It probably was easier than going through the top to reach the top of the battery case.   The end result was that I reached the pin without damaging the function of the IC (I think).   I was surprised to measure the battery at 3.304 volts!   So it appears that it still has considerable life left.   Dr H. Holden claims in his article that it remains functional down to ~1.8 volts.

But in the process, I ran into an unexpected snag.   When I reached the first sign of metal, while following Holden's sketch on page 6 of his article, I tried to read the voltage, but kept getting zero.   So I kept excavating and testing with no progress.   Finally, returning to square 1 and working back through everything, I found that his illustration was wrong!   Important to know for anyone else trying the same.

His illustration shows a bottom view of the DS1225Y.   But the 2 rows of pins are transposed - move the upper row straight down and the lower row up and all is well.   Looking at the illustration, I had the meter lead clipped to the "Gnd" on the lower right pin, and it should have been on the upper right.   He has another illustration on page 21 which is a top view of the DS1225Y and those pins are not transposed.

Over the last many days, I've powered up the scope to confirm that all is well.   But recently the previously mentioned bug occasionally reappears.   It always happens on power on when it goes through its health check.   Some times it stops with all 1's and dashes where the readouts should be.   It has also read "TEST 03 PASSED."   One time it stopped reading "ALL 00   FAIL 03."   Another time it read "TEST 03   FAIL 02," which the lookup says is "Readout Ram failure."   It did this this before I replaced the DS1225Y.   But in all cases, pressing "A/B TRIG" returns the scope to normal operation where everything is perfect.   I even retuned to test mode and started it looping through all the startup tests and left it run for an hour with no hiccups.   I have some remote ideas to look at, and I want to recap the power supply.   Thanks to MSO I have his capacitor list for guidance.

FireDragon - Thanks for sharing.   A lot of good info on this site.   Starting at the beginning with BravoB's 1st entry it took a long time to read it all.   But like a best seller, it was hard to put down.

Thanks DSO for all the tricks in using a vacuum tool.   Yes, I was using the small, 1mm tip too.   I'll get more experience on the PS board. 

 

Offline Bryan

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Re: Tektronix 2465B oscilloscope teardown
« Reply #658 on: February 25, 2016, 06:58:22 am »
I well up in tears when I read users who successfully replaced their DS12257. I tried replacing mine  a year or so ago, did everything right in prep, unsoldering properl. Went to read it on the programmer and all the data was 00 or FF, can't remember, something went wrong during the removal process and it erased the memory. Tried all the tricks I could dig up in trying to recover, but I guess the battery in mine was at the point that the removal or memory read brought the voltage down ever so slightly past the threshold and everything was lost. Didn't know at the time that the memory was available on screen, could have taken some pictures and added the data back manually to the new chip with the programmer. Oh well.
-=Bryan=-
 

Offline casinada

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Re: Tektronix 2465B oscilloscope teardown
« Reply #659 on: February 25, 2016, 07:10:31 am »
If you lost your data ( I did) you can use somebody else's backup as a starting point, that way your scope might be out of calibration but it will be easier than to start from scratch. In some cases it will come back without showing errors. Calibrating can be lots of fun. I had to do it with my 2465BDM  :)
 

Offline Bryan

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Re: Tektronix 2465B oscilloscope teardown
« Reply #660 on: February 25, 2016, 07:11:54 am »
Yes, that's what I did, had to try a number of backups that are available, I think I came close, but it still will need a full calibration.
-=Bryan=-
 

Offline Old-E

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Re: Tektronix 2465B oscilloscope teardown
« Reply #661 on: February 25, 2016, 04:04:30 pm »
Bryan - Yes, I remember reading a ways back about losing your memory.   Bad news!   But maybe - I'm new to all this - but some thoughts are, you might try reinstalling it back into your scope to see if it may still work.   If you happen to have installed a socket, it would be an easier install.

Another (better) thought is; according to Holden, the battery could go below the threshold level of the embedded DS1218 battery controller.   But the memory is not actually gone.   In that case, an external battery could be piggy backed on to the DS1225Y to bring the voltage back up.   Then it could be read on the programmer.   As written below, I just excavated down to pin 7 of the battery controller for the positive battery connection.   Then the return line goes to pin 14 on the DS1225Y.   That can be done in a hour or so.

Another possibility could be that a lack of static control might have caused a non-fixable problem.   From what I could see, shorting the pins should not be a big deal.   Maybe if shorted for a long time (years) , it might speed up the discharge of the battery.
 

Offline Old-E

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Re: Tektronix 2465B oscilloscope teardown
« Reply #662 on: February 25, 2016, 08:10:08 pm »
More thoughts.   To avoid soldering to the the dead DS1225 before inserting it into the programmer, one could connect the external battery return wire to pin 14 by just looping it around the top of the pin, or inserting the return wire into the pin receptacle of the zero insertion force socket of the programmer.   Likewise, once pin 7 (+battery point) is exposed, one could just hold a sharp pointed probe on the pin during the programmer read time.   Again, no soldering to the DS2018 pin.   And it is my guess, that even if your battery connections are noisy, the existing battery will take on a certain amount of charge which will produce a constant voltage above the threshold to the DS1225Y during the read time.   This is all for a temporary read, so make shifting might be a safer and quicker way to go.

Picture below is of my DS1225 after excavation.   And I removed more potting than necessary for a temporary connection.   The exposed metal pin is visible next to the body of the DS2018.   Excavation was accomplished with a pointed X-acto Knife and a needle pointed probe tip.   The biggest challenge was in to minimize bending the DS1225Y pins during excavation.
 

Offline Bryan

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Re: Tektronix 2465B oscilloscope teardown
« Reply #663 on: February 26, 2016, 04:44:51 am »
Thanks, yes I had tried that when I originally attempted to replace the Dallas. No luck at the time, may try again, perhaps I may get lucky. But doubt it. The voltage of the battery was less than a volt.
-=Bryan=-
 

Offline Old-E

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Re: Tektronix 2465B oscilloscope teardown
« Reply #664 on: February 26, 2016, 04:00:11 pm »
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.
 

Offline Bryan

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Re: Tektronix 2465B oscilloscope teardown
« Reply #665 on: February 27, 2016, 09:39:31 am »
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.

The voltage of the battery is after it had been in storage for over a year. Always thought there was a hope of recovery, but nope. Tried again on the programmer and all I get is 0x00 and 0xFf in what seems to be 3-4 banks of memory. I am not sure what went wrong, could have been anything. Still kicking myself for not taking pictures of the CRT that shows the memory allocations. Would have been a lot of work to rebuild, but at least I would have had something.

I have a TG501 and a SG503 so think I have the basics for a decent recalibration by myself. Just need to put together some accurate voltage references. Although going by memory the voltage levels have to be a square wave. Can probably use a function generator and calibrate the voltage level. Just needs to be within 3% anyways. I find I don't use the scope much, handy if I want to look at some higher frequencies than what my Rigol DS1052E can do. Afraid the days of the analog scope are becoming closer to a end, just so much more you can do with a digital scope. Although nothing sweeter than the glow of a CRT, one of the reasons I still keep it<g>
-=Bryan=-
 

Offline Old-E

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Re: Tektronix 2465B oscilloscope teardown
« Reply #666 on: March 01, 2016, 06:33:28 am »
Seems that everything has its share of kinks (trivia reporting).

Got together with my programmer friend yesterday to get the stored cal data transferred from my old XP computer, into the 2 spare IC's.   I had soldered the spare FM16W08 onto the adapter board and the spare DS1225AD had arrived, so repeating the data transfers should have been an easy task.   We started out by reading what was on the FM IC, and that appeared to work.   So we tried to perform some simple tests, like entering all ff's for example, and it would not complete the write,   Tried transferring real data into it with similar "failed" status.   So thinking that maybe the FM IC had a problem, we plugged in the new Dallas IC and had similar problems.   After spending a few frustrating hours on trying to get something to work, we decided to at least get a screen print of the data file from the programmer so that I could have a hard copy for my note book.   But then could not get the printer to work without freezing up.

Decision was finally made to quit for the evening with a plan to start at square one on Monday.   So, today I put in a call to my Computer Angel service, that I have available on call, to go through the older XP computer to get it cleaned up and debugged if needed.   Once I feel comfortable with that, then the plan is to reload software into the programmer, etc.   Eventually we'll get it - I hope.   But at least we have a new working FM IC in the scope - whew!

Today the computer allowed me to get a hard copy of the cal data printed out so something is strange there.   With cal data printed out, I was then able to easily compare that with the hand copied data from the scope CRT.   It takes awhile, but it can be done.   This turned up about a dozen errors.   From that, I compared the errors directly with the digits on the CRT.   Bottom line was, in all cases the printed out data from the programmer agreed with the data read off the scope CRT.   This is what should be, but just wanted to confirm that.   In most cases, the errors were where the spine of a B or the left edge of a 3 was perfectly centered under a vertical reticle line.   So using an eye loop and fuzzing out the focus a little, I was able to see the spine of the B showing on both sides of the reticle line.   So I think my hand copied data off the scope screen, and the printed data from the programmer is now all correct.   So while some things are coming together, it's not without its challenges and set backs.
 

Offline MSO

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Re: Tektronix 2465B oscilloscope teardown
« Reply #667 on: March 03, 2016, 05:56:33 am »
OLD-E,

I just spent the better part of hour writing a response to your last post and then a made a typo of some sort and lost the entire post. The replay window simply disappeared. That’s probably much better for you as I now, by rewriting the response, I can eliminate some of redundancies and extraneous comments.

I would expect some differences to exist between the NVRAM currently installed in the ‘scope and the DS1227 that you replaced.  Running time, the On/Off count and the set up in effect the last time you used the scope come to mind.  I’m not sure if there would be any changes made to the calibration area of the NVRAM; for instance balancing the channel 1/channel 2 inputs might end up there.

When you have doubt about your programmer reading the device properly, you’ll find a tool such as Beyond Compare to be invaluable.  Simply read the NVRAM device in the programmer, save it to a binary file then read it again and save to a second binary file. Using Beyond Compare, compare the two files just read. If there are differences, then you know the programmer isn’t reading properly.

Be aware though, that many programmers keep the data they last read in an internal buffer and won’t modify that saved data if they can’t read the device a second time. So it’s best to force the programmer to dump the data in its internal buffer before reading the device a second time. If the programmer’s software allows you to directly edit its buffer, insert a series of known values near the start of the buffer; I’ll usually use a few series of AA, 55, AA, 55 values to ensure that the programmer actually read the device a second time.  Depending upon your programmer/software, you may have to close the software and restart it again or try loading a different, unrelated binary file between first and second reads.

You can use this approach when comparing reads between two different NVRAM devices as well. If one of the devices has more memory than the other, then just ensure that the two devices match up to the size of the smallest device.
 

Offline ChunkyPastaSauce

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Re: Tektronix 2465B oscilloscope teardown
« Reply #668 on: March 03, 2016, 06:09:01 am »
Question...

I bought one for basically nothing because from a university. Basically nothing because it doesn't work....other than that,very good condition  ::)

The calibration is probably still there as the date code isn't that far out.

It likely died due to a very failed fan. I measured the voltage rails..... they are all over the place. Some of them are low and if I remember correctly....some of them higher than they should be.

So my question...... is it worth trying to fix the PSU when some of the rails are higher by like 150%? Or is it likely the higher voltage damaged other parts of the scope and not worth the effort?
« Last Edit: March 03, 2016, 06:10:32 am by ChunkyPastaSauce »
 

Offline MSO

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Re: Tektronix 2465B oscilloscope teardown
« Reply #669 on: March 03, 2016, 07:36:16 am »
ChunkyPastaSauce,

I'm not knowledgeable enough to answer your primary question (is it worth it), but having re-capped both power supply boards and the A5 control board for roughly $50, I'd say it's worth a shot. My suspicion is that the overheating may have damaged a couple of the main board chips, but for $50 and little time and effort (for me it's an enjoyable hobby) you can determine if its worth pursuing further.
 

Offline Bryan

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Re: Tektronix 2465B oscilloscope teardown
« Reply #670 on: March 04, 2016, 02:01:46 am »
The 2465B is pretty rugged and well designed, I would invest in the time and cost to get the power supply fixed and go from there. More than likely the caps are toast and there may be some other issues on the power supply board. If you scour the service manual you will see that much of the other circuitry on the power supply board and other boards have pretty good protection if something goes wrong on the power supply side of things.
-=Bryan=-
 

Offline ChunkyPastaSauce

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Re: Tektronix 2465B oscilloscope teardown
« Reply #671 on: March 04, 2016, 03:10:55 am »
Ok, thanks to both  :) It looks to be a nice scope, certainly better than the working one I have now (which isn't bad either tek2235).
Typically pass on doing anything on PSU high sides.... basically they frighten me. Also the fact there is a CRT. Right now, I'm nervous about getting the board out.....

Ive checked the main caps on the PSU for residual charge at the black plastic shield check points, they are empty. Anything else on the PSU board I should be aware of that may have the potential to make me have regrets messing with it? Or generally pretty safe if the charge check points, at the black plastic shield, are around 0V? 

I've check all the caps for obvious problems that can be checked, without having to pull the PSU boards out.

Thanks again.
« Last Edit: March 04, 2016, 03:14:23 am by ChunkyPastaSauce »
 

Offline Old-E

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Re: Tektronix 2465B oscilloscope teardown
« Reply #672 on: March 04, 2016, 03:31:56 am »
Chunky,

I happen to love the fine qualities of my Tektronix 2465B scope (assuming that's what you have).   For me, it's worth the dollars & effort to have a reasonably great and high performance scope, not to mention the education and hobby element.   From what I've seen on E-bay, these scopes in good clean condition and working perfectly are going for $1,000 - $1,400.   I saw a copy of an old brochure (circa 1990) advertising a new scope like mine for $9,200.

But if your thoughts are to get it working in order to turn a quick profit, well, that might work if you value your time at 10 cents an hour (exaggerating, well maybe).   If your interests are profit (nothing wrong with that), then you might be better off parting it out on E-Bay or selling it as is.

My concern would be that the failed fan, followed by failed power supplies, leading to over voltage conditions, could have wiped out many IC's, etc.   This could be a costly / time consuming over hall relative to the numbers we're talking about.    You say the memory IC has a recent date stamp.   But if it's older than 10 years, which is the guaranteed life, then you should be looking at replacing it.   The cost of a replacement IC, or later version with no life limits, plus a programmer will total about $150.   The other parts, as MSO indicated, are fairly cheap, providing all the mechanical stuff is ok.   Then there is quite a bit of labor.

But, if you are interested in, and reasonably ok at working with electronics, and would find a project like this rewarding, then this could work well for you.   Forums, like this one, are a treasure trove of information and help.   Others here may have different thoughts. 
 

Offline ChunkyPastaSauce

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Re: Tektronix 2465B oscilloscope teardown
« Reply #673 on: March 04, 2016, 06:06:00 am »
Hi Old-E

Yep it's the 2465B 8) If I can get it working, not selling it, unless it's not for me for some reason. I bought it for fun at $35 knowing it would be some level of a project and knowing I might not be able to get it working at my skill level, somewhere beginner-intermediate hobby range (I'm a ME not EE). If I can, great, if I can't then no big deal and Ill probably put it up for anyone willing to pay shipping if they want to have ago at a fairly desirable analog scope or need parts.

I went ahead and pulled the inverter and regulator boards out.. Nothing too horrendous looking (the board is very clean by the way, no dust except a cm or 2 at the fan entrance). The rectangular cap packages, a number of those are somewhat bloated...almost all have hairline cracks. The other caps looked ok visually, except possibly some of the silver guys near to bottom but hard to tell (Edit - found some baddies after removing  :-+). I checked the diodes and all of them seem reasonable.. I thought I found some bad ones but after lifting they were fine... got excited for a few.

So Ill pull the caps; although I plan on replacing all anyway, ordering ESR meter for fun.


On the date code, I was reading about that. I thought it was 20 year life but now looking at the spec sheet..... uhoh lol. We will see...  Wouldn't the cal data be kinda useless after repairing the power supply board, it would need a recal anyway?

Thanks again
« Last Edit: March 04, 2016, 06:35:33 am by ChunkyPastaSauce »
 

Offline ChunkyPastaSauce

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Re: Tektronix 2465B oscilloscope teardown
« Reply #674 on: March 04, 2016, 09:51:35 pm »
Baddies.



All of these probably, hairline cracks on case likely ballooned caps
« Last Edit: March 04, 2016, 09:53:55 pm by ChunkyPastaSauce »
 


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