Products > Test Equipment

8116A Code 42

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MarkL:

--- Quote from: Mick B on June 28, 2024, 02:49:59 am ---OK Good news, I could not find the old U37. But I did find another chip from a different vendor and the results are
U37.15
Power on -1.77V
pushing the MAN button once -1.28V
pushing the 1 cycle button once -1.77V
pushing 1 cycle one more time -0.785V
and one more time and back to-1.77V
I pushed these buttons in this order right after power on. I believe I had a bad chip, It is mildly warm

--- End quote ---
The replacement is mildly warm?  If so, that sounds a lot better.

Those voltage levels are also good, except the -1.28V.  That's in between HIGH and LOW.  Are you still measuring these values with scope?  Maybe it's pulsing?


--- Quote ---I have enough 1% resistors to get -.7V  if you think that might be something to look into when this comes to and end. or leave well enough alone
Tomorrow, I will post the results of the whole chip, Put U33 & U34 back in and see  what's what

--- End quote ---
Looking back on the measurements from my unit, it's also not -0.7V (it's -0.93V).  I think there was an error in calculating the resistor values in the design, and/or that node should not have been labeled "-0.7V".  But obviously it's working.  We should leave this alone.

Interested to see what you get with U33 and U34 back in circuit.  With the prior measurement reporting errors, it's possible the old ones were ok.

Mick B:
Sorry Mark to take so long to get back to you, I have been very sick. I caught the flu & got a sinus infection at the same time. I still feel like shit, but I couldn't lay in the bed another day, thank God for antibiotics.
Here is the newest reading of U37, U33, U34 with all chips in. Settings:  Mode, EBUR 14. Frequency 1K, Wave NONE, Amp 1V, offset NONE, output ON. ALL voltages checked with my Rigol 5354 Scope. AND on U37 pins 11. & 14 my HP 34401A multimeter these voltages seemed low hopefully these are close enough to evaluate.  I have done a self-calibration on my scope It takes almost an hour. If you think I need to redue these I will. Right now, I'm going back to bed apparently, I don't feel as well as I thought I did  :-BROKE   
   U37
  4. (I) -2.17 V
  5. (I) -2.15 V
  2. (O)-1.17 V

  6. (I) -1.77 V
  7. (I) -1.76 V
  3. (O)-1.70 V

10. (I) -5.22
11. (I) -0.460 V ...NOTE: HP Meter 0.513 V   
14. (O)-0.671 V ...NOTE: HP Meter 0.739 V   

12. (I) -0.735 V
13. (I) -1.71 V
15. (O)-0.722 V
  9. (O)-0 V

    U33
  4. (I) -1.70 V
  5. (I) -0.715 V
  2. (O)-1.77 V

  6. (I) -1.64 V
  7. (I) -1.69 V
  3. (O)-1.78 V

10. (I) -1.69 V
11. (I) -1.79 V
14. (O)-1.78 V

12. (I) -0.904 V
13. (I) -0.710 V
15. (O)-0 V
  9. (O)-1.76 V

    U34
  4. (I) -1.69 V
  5. (I) -1.78 V
  2. (O)-1.77 V

  6. (I) -0.735 V
  7. (I) -1.69 V
  3. (O)-1.78 V
 
10. (I) -1.69 V
11. (I) -0.715 V
14. (O)-1.77 V

12. (I) -0.903 V
13. (I) -1.68 V
15. (O)-0 V
  9. (O)-0.731 V

MarkL:
No problem; I hope you are feeling better!

Except for U37.2, between all the other U34 U37, U33, and U34 readings you posted, there aren't any readings that are out of range of ECL logic levels, or inconsistent with the gate functions.  That doesn't mean they're necessarily working, but perhaps we're almost passed the point of locating shorts and similar issues using this static measurement method.

U37.11 is coming from a level shifter, so I'll give them a pass on being a little outside a normal ECL HIGH.

Is anything still getting hot?

On U37.2, you are reporting it as -1.17V, which is between an ECL HIGH and LOW, but on the other seven pins attached to this node you are reporting it as -1.70V.  Was U37.2 a mistake?  If a mistake, then I would say all the nodes are consistent.

It might be interesting to see if anything is working now on the burst function by setting the unit to internal burst mode (I.BUR).

EDIT: Fix typo.

Mick B:
Feeling a little better today, no fever. Apparently, that U37.2 reading was an error, I wrote down -1.71 but typed -1.17 dyslexia strikes again, I try very hard to catch these. The hottest chip on the board U34 @ 46.2C So all is well......? almost I'm still having issues with the BUR light intermittently working and I wonder about the error light, not exactly sure when it is supposed to come on I read it somewhere but don't remember where. as I adjust the timing depending on other settings, I can make the error light flash.
I did the performance test for Burst mode, it made it up to 816 in EBUR and I looked at EBUR & IBER on my scope and it looked good, if I understand IBER, it just keeps repeating what you have it set at, Correct? I have never used this mode before. The sweep mode also works.
This adventure so far has been just Great.  :-+

MarkL:

--- Quote from: Mick B on July 02, 2024, 08:53:38 pm ---...
The hottest chip on the board U34 @ 46.2C So all is well......?

--- End quote ---
ECL dissipates heat even if nothing is switching, and that temperature is fine.  I don't think you have any internal shorts now.  So that's good.


--- Quote ---I'm still having issues with the BUR light intermittently working and I wonder about the error light, not exactly sure when it is supposed to come on I read it somewhere but don't remember where. as I adjust the timing depending on other settings, I can make the error light flash.

--- End quote ---
The error light comes on when the settings don't allow the unit to complete a triggered event before the next trigger comes along.  For example, in burst mode it would be an error if the repetition rate was too short and did not allow the set number of burst pulses to occur.  An error could also be casued if the repetition clock and/or pulse clock were not in spec (i.e., could cause the current event to get overrun by the next event).

Keep in mind all the time related circuitry on this unit is analog, so the exact settings where the error starts to occur is going to vary a little.


--- Quote ---I did the performance test for Burst mode, it made it up to 816 in EBUR and I looked at EBUR & IBER on my scope and it looked good, if I understand IBER, it just keeps repeating what you have it set at, Correct? I have never used this mode before. The sweep mode also works.
This adventure so far has been just Great.  :-+

--- End quote ---
If it passes the performance verification, that's good.  That's correct on I.BUR.  It will keep repeating the set number of pulses, and will have a gap at the end if the repetition time permits.  E.BUR waits for a manual or external trigger before emitting the set number of pulses.

Is there anything that's not working now?

Does the error light come on unexpectedly?  If so, under what conditions and what is the resulting output?

EDIT: typo.

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