Author Topic: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair  (Read 25441 times)

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Offline Rufus

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #50 on: January 01, 2014, 07:58:45 pm »
Well, if google has anything to say:

http://www.seekchip.com/icstock-m/MM9576-VJG.html

The MM numbers are date or batch codes the part numbers are ADG.

The ADG365 is mentioned in a Tektronix patent about some video triggering scheme. It is described as a trigger circuit controlling a sampler.

 

Offline vikpc

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #51 on: January 01, 2014, 08:00:24 pm »
im think need swap hybrid modules betwen channels to check where is problem.. 8) Dave have cool desoldering station.. its about 10-20min to swap
 

Online georges80

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #52 on: January 01, 2014, 08:42:44 pm »
Well, if google has anything to say:

http://www.seekchip.com/icstock-m/MM9576-VJG.html

The MM numbers are date or batch codes the part numbers are ADG.

The ADG365 is mentioned in a Tektronix patent about some video triggering scheme. It is described as a trigger circuit controlling a sampler.

Given the parts are NS and MM is an NS part number 'starter', I'd suggest those are NS part numbers. The ADGxxx may be a branding for Tek. MMxxxx doesn't look anything like a typical batch/date code - the stuff below the MMxxxx is more likely that info.

cheers,
george.

 

Offline sync

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #53 on: January 01, 2014, 08:56:02 pm »
im think need swap hybrid modules betwen channels to check where is problem.. 8) Dave have cool desoldering station.. its about 10-20min to swap
... and risk to destroy another channel.
And probably you should not touch the hybrids which makes swapping a bit difficult.
 

Online PA0PBZ

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #54 on: January 01, 2014, 09:50:09 pm »
Did Dave say he'd uploaded #565, part two? No sign of it here yet :(

There, There.... he only said he shot it. I'm sure we'll see it soon enough  ^-^

There: https://www.eevblog.com/forum/blog/eevblog-565-tektronix-tds3054-oscilloscope-repair-part-2
Keyboard error: Press F1 to continue.
 

Online jancumps

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #55 on: January 01, 2014, 10:42:26 pm »
I find it frustrating to watch your fault finding/repair videos.
Initial mechanical inspection and some speculation is OK to a certain point, but don't go overboard.
I don't kow why you avoid using electronic test equipment to do at least some basic measurements?
You have a multi channel scope, you could easily do some signal comparisons on the front end.
At the end of the day it may not resolve the issue, but for **** sake you are running en electronics blog/forum.
Yeah... as a software engineer, the random poking around kind of makes me cringe. The term we use for that is shotgun debugging. My approach would be to use bisection to find the problem area. In this instance, you've guessed at what some of the traces on the boards do, let's probe them with a scope at various points to see whether the fault exists before oYr after that point. Why waste time with random wild shot guesses.

On the other hand, since Dave is commenting on the various bits and pieces he examines as part of the random wild shot guesses (Dave: hey, at least they appear that way in the video. If you've done a more methodical problem analysis, it's not in the video. If I've stepped on your toes here, I'm sorry :) ), I find the video interesting to watch. There's still so much I don't know, and what might be an off-hand side comment to you is really an information nugget to me.

I'm also from software side and I disagree ;)

There is a substantial difference. Hardware has a much bigger physical component in it. Software debugging is almost always about logic that's  failing.
There is nothing wrong with (seemingly) random poking at and looking at parts of the scope - to see if something looks bad - before digging deeper into it.

chances are quite high that a failure is visible or smellable.

When that faiils it is the right time to get into a more structured approach like described above.
 

Offline Saneoc

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #56 on: January 01, 2014, 10:55:03 pm »
Hi all!
First of all, I'm sorry for my english, but I want to say something.
  The strange thing I notticed is the fact that the noise is always above the trace at the positive half cycle and mostly below the trace at the negative one (or near zero).
Probably this can be caused by some adc logic error, but I don't know how to test it.
 

Online jancumps

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #57 on: January 01, 2014, 10:57:02 pm »
In the follow up video, noise is on both sides with a sinus 1KHz test signal.
 

Offline Saneoc

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #58 on: January 01, 2014, 11:07:19 pm »
I saw it, but there the clamping is also present.
  You may notice that at some point the polarity of added signal is changing.
 

Offline vaualbus

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #59 on: January 01, 2014, 11:24:40 pm »
I will not consider noise to be a problem, it could be due to a lot of factors. Remember that the scope not working in their perfect condition so it could be normal.
« Last Edit: January 02, 2014, 08:45:13 am by vaualbus »
 

Offline EEVblog

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #60 on: January 01, 2014, 11:41:14 pm »
Did Dave say he'd uploaded #565, part two? No sign of it here yet :(

There, There.... he only said he shot it. I'm sure we'll see it soon enough  ^-^

It usually takes 12-24 hours or overnight for the video to upload, process, and then monetise before I can release it. And that's after the editing.
 

Offline KarolNi

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #61 on: January 02, 2014, 10:52:42 pm »
I've watched 2nd part, but I spotted something in 2:39 in this part. Noise seemed to be periodic - I think it might be some coupling and heterodyning with other periodic signal - clock or dc converter ripple, maybe on digital side. It will not be handy, but maybe some off-circiut check of decoupling capacitors?
For 2nd video I'm curious about negative voltage on broken diode vs. positive on operating channels - but this wouldn't be issue IMHO. Dave, have you checked voltage on pads after desoldering diode?
Last thing - maybe some phone procedure (factory reset, reflash with newest firmware, if available and recalibration) will work?

Good luck!
Karol

Edit: I mean heterodyning sample clock with ripple or other clock.
Karol
« Last Edit: January 03, 2014, 08:52:14 am by KarolNi »
 

Offline burra7

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #62 on: January 04, 2014, 10:11:48 pm »
DC ripple sounds interesting. I tried to have a look and the ripple seems like 50kHz. Might be an idea to measuere the DC rails +5V1, -5V1, +15V and -15V to see if we can find the ripple there also.

Have made a block shema also:
https://bitbucket.org/burra/tds-3054/src
« Last Edit: January 05, 2014, 08:50:51 am by burra7 »
 

Offline Wim_L

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #63 on: January 05, 2014, 06:16:30 pm »
A close look at the video in dots mode. 6:21

It seems the noise is quantised, a group of dots gathering, but in discrete steps, not as a smooth noise band. Perhaps something to investigate? A certain subset of the 9 bits failing or going random?
 

Offline M0BSW

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #64 on: January 05, 2014, 08:15:37 pm »
And we have no forum members at Tek who can dust off somebody to give their thoughts?
Actually there is Alan W2AEW  a Tek employee, Very helpful fella , I'm sure you'd just have to ask him for his thoughts and He'd help
« Last Edit: January 05, 2014, 08:18:32 pm by M0BSW »
no one would or will tell me how to delete this account
 

Offline R_G_B_

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Re: EEVblog #564 - Tektronix TDS3054 Oscilloscope Teardown Repair
« Reply #65 on: March 16, 2018, 12:59:27 pm »
I am to having the noise problem on high sampling rates

E.g noise when the time base is below 400us.

I narrowed this down a bit as follows.

10k points the noise appears below 400us @ 5Meg samples.

At 500 points sampling this happens below 10us at 5Meg samples

Because of the decimation in sampling points there does not seem to be as much noise in the display but it is there and it seems to be low  frequency ripple And Wonder of the signal. Could this be a fault with the triggering circuit. Open circuit resistor seems that the error message complaint is about the termination resistor being to hot. 4KTBR watts Boltzmann's constant having anything to do with the noise at higher sampling rates with intermittent or resistance ?

Just some thoughts
R_G_B
 


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