Products > Test Equipment
Agilent 54845A Failing all trigger self tests
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TRN:
Tony,

Thanks and you were right, about the regulator.

The divider values are R1= 120 ohm; R2= 260 ohm. This means the regulator is set to output 3.96 volt, and I check Uout across the divider network, and the output is 3,96v. R2 however is not connected to ground, but to a node which is at -3.1v from ground, so that's why I am measuring 0.85v between the regulator output and ground.
In a nutshell, the regulator is O.K., but I still am unable to figure out how can it be that one should measure +3.9V? on pins 16 & 11?


nctnico:

--- Quote from: TRN on May 01, 2018, 07:32:00 pm ---nctnico,

Thanks for the tip, however I have a hard time finding the HP4XS.HLP file on the scope, I also tried to extract the file from the Ghost image using GhostExplorer, but I was unable to do so because GhostExplorer crashes every time I try to extract anything,

Can you send me a copy?

--- End quote ---
See attachement:
Tony_G:
I find it interesting that there is supposed to be a -3.1 rail and you're reading 0.8 instead of -3.9.

Might be a simple coincidence but it might be an indication of something wrong with the rails. Is pin 16 meant to be the -3.9v rail? I believe that it is but I've never checked on my scope (I had issues with the attenuators but not the power supplies).


Pity we don't have a schematic.

TonyG
TRN:
nctnico,

thanks for the help file, now I only need to find a PC which runs Win XP or 7  :-+

Tony,

Thanks, and according to Matthew Dasaro, pin 16 is the -3.1v rail for the analog Hybrid. I will do some more board probing to see if this correct, and if I can make some sense out of this.

Anyway, I agree with your comment about the schematics, and I really do not understand that these are not available somewhere. I mean HP/Agilent designed this scope, so they must have had the schematics.
I am quite sure that there is a retired HP design engineer somewhere who has the whole documentation package laying on his desk with a pile of dust on top of it :).

Anyway I will get back once I have any news

TRN:
I am still trying to fix the the trigger self-test errors, and I am looking for the pin-out of Motorola MC10H105 and MC10H117 Ic's in a PLLC-20 case.

The ON Semiconductor datasheets only show the pin out for 16 pin dual in line packages.

Can anybody tell me where I can find the ones for the PLLC-20 case?
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