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Agilent 54845A Failing all trigger self tests
TRN:
Thanks for the advice, and I already checked the board for soldering flaws, but it is quite possible that I have overlooked a bad soldering joint.
Anyway, i should get the IDE drive latest by friday, and if restoring the firmware doesn't work, I will do another check.
Regards
TRN:
Hello Tony,
It took a bit longer then expected because the HDD went defect, and I had to buy a new 40GB IDE drive. I burned a CD from your 5484xBRecovery.iso file (inside directory\54845\548xx\Upg_Rec\5484xB\) but the iso file is corrupt.
So I used the v4.30 recovery and v4.50 upgrade software which I previously downloaded from the Keysight FTP.
The result is the same meaning that none of the trigger events passes the self-test.
So I followed nctnico's advice and have checked the board for any soldering flaws, but haven't been able to find any so far.
I also read the article from dasarodeigns.com, (thanks for the link nctnico)
I checked all the Voltage regulators and except forXU5 and XU19, they all match the values listed.
XU5 and XU19 measure respectively +7.09V & +7.12V instead of +8.5V, but I don’t think that this interferes with the scope functionality, because it looks that they only supply power to the two large cooling fans.
I also checked the attenuator connector pin-outs, and there some differences with the values listed.
J7 & J9:
Pins 20: (+ 1.61V with attn installed); (+1.71V w/o attn installed)
Pins 16: +0.845V
Pins 8: (-2.78V with attn installed); (+1.8V w/o attn installed)
J6 & J8
Pins 20: (+ 1.61V with attn installed); (+1.71V w/o attn installed)
Pins 8: (-2.78V with attn installed); (+1.8V w/o attn installed)
Pins 11: +0.845V
Pins 16 from J7 & J9: and Pins 11: from J6 & J8 are all fed from the same regulator U45 which is an LT 1086. which outputs + 0.85V, so I am puzzled how can it be that one should measure +3.9V? on pins 16 & 11?
any ideas are welcome
nctnico:
In the software directory your can find various help files. Look for HP4XS.HLP. This contains some information on how to diagnose the scope at the board level. It isn't a complete service manual but it might contain enough information to get you in the right direction.
Tony_G:
--- Quote from: TRN on April 30, 2018, 07:06:29 pm --- Pins 16 from J7 & J9: and Pins 11: from J6 & J8 are all fed from the same regulator U45 which is an LT 1086. which outputs + 0.85V, so I am puzzled how can it be that one should measure +3.9V? on pins 16 & 11?
--- End quote ---
Datasheet for that LT1086 is here. Can you confirm that it is really supposed to be 0.85V? That doesn't seem right as that part is supposed to have a 1.25V different between Vout and Vadj. What are the R values for voltage divider on that part?
TonyG
TRN:
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?
regards.
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