Electronics > Repair
HP 3458A - Fails Slave Test - Convergence
IanJ:
--- Quote from: Ade911 on May 15, 2023, 08:26:04 pm ---Update
Purchased a GQ-4x4 programmer , removed all Dallas devices and copied data to new ones , replacing in the meter , now suffer from needing all calibrations......
--- End quote ---
Did you try extracting the Cal data via GPIB first?
There are a few methods to do so.
Theoretically, extract the ram data, (peace of mind achieved that you have it all backed up), then send to a programmer and burn the new Dallas ram IC's without disturbing the existing ones until you really have to.
There are different variants of the Dallas ram IC's.
PS. I use a Dataman S4 programmer.
Ian.
coromonadalix:
some search here may helped
https://www.eevblog.com/forum/repair/minor-repair-hp3458a/
https://www.eevblog.com/forum/repair/hp3458a-sram-replacement-copy-or-calibrate/
https://www.eevblog.com/forum/metrology/yes-another-3458a-repair-and-nvram-replacement-to-ramtron-fram/
https://www.eevblog.com/forum/metrology/3458a-how-do-i-read-the-dallas-non-volatile-sram-date-codes/
https://www.febo.com/pipermail/volt-nuts/2009-August/000052.html
https://www.febo.com/pipermail/volt-nuts/2014-August/003482.html
https://xdevs.com/fix/hp3458a_u4/
https://xdevs.com/fix/hp3458a/#diag1 repair of the slave test convergence ?? and some software down the page
https://xdevs.com/article/hp3458a_gpib/#calgpib
coromonadalix:
Annnnnnnnd this software piece to control the meter and do the nvram backups
https://www.eevblog.com/forum/metrology/3458a-logging-via-windows-app-revisited/
1st reply down
https://www.eevblog.com/forum/metrology/3458a-logging-via-windows-app-revisited/?action=dlattach;attach=1782284
Dr. Frank:
@ ADE911:
It's a pity that you did not use the search function of this forum upfront, and you listened to people who don't even own a 3458A.
The TL866 plus would have been the better and maybe cheaper solution. It would have been necessary to download calram content via GPIB first.
Now, after all these unthoughtful changes you made, it seems that calibration constants are probably lost.
Frank
Ade911:
Thank you all for your advice and feedback, yes not proud of what i did but you sometimes get to a point where you do big changes usually around 2AM.
I don't have a GPIB interface so hence the decision to very carefully remove the Dallas chips and copy. I've attached copies of the data uploaded from the chips, I believe its still ok unless I dropped a bit somewhere or you think otherwise.
Re your advice and comments below, Ill carry these out today and report back.
For debugging the input amplifier it would help to start with the non AZ mode, though with a stable 0 V at the input it would not make a difference.
For the 10 V range pins 1 and 2 of U103 should be at the negative rail, some -18 V.
Pin 14 should follow TP100 = the amplifier output.
TP101 as the buffered feedback signal is also of interest.
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