开云体育

Hi all,

I got a TDS520 from a friend. The pcbs are perfectly clean , have no dullness. Now I still have "FAIL ++ Aquisition" at self test, but all

channels are working very good with zero offsets, full bandwidth, timing, amplitude, and all triggers are perfect.

I did the SPC and got always only this error message:

ERROR: 2260 Calibration failed
Triggers

ERROR: Diagnostic test failure
logicTrigConfDiag, STRIGA must be high when triggered, wasn't for gamma comparator";"

What the heck does this mean ?
Where I have to look for trouble shooting ?

I don`t know were to start.
Can anybody help me out please.
Thanks

Hi,

After long hours of measurements, cleaning etc. I had a final look at the acquisition board again and identified a suspiciuos via close to one of the infamous SMD caps ( see pic ).
I traced it and it turned out it was eaten up by the electrolyte.
After replacing the track with a wire the scope booted w/o errors and passed SPC.
What do we learn ?
Check all vias close to caps and pray they are not hidden underneath a part.
The broken connection carries the TRIGCC"B" signal between U1551 pin 26 and U624 pin 14.
One possible hint : SPC showed the following errors :

0x51efee4 (V main): TRIG"beta" trigGain[ CH1 ] 0.0 set to coldStart value
0x51efee4 (V main): TRIG"beta" dcOffset[ CH1 ] -1.6991698 set to coldStart value

Best regards
Hans