Agilent B2902A SMU - Page 1
Forum section: electronics / repair

author: hobbyelectronics
author_rank: Regular Contributor
timestamp: November 29, 2023, 03:55:18 pm
content: Hello,I recently purchased a Agilent B2902A SMU as a non working unit.I was told that a firmware update had failed and basically has bricked the unit.It powers on but the screen is just blank.I believe that it is only good for the scrap bin or for spares.Before I strip it down to salvage any bits, I thought I would ask if it is possible to recover from this?Even at a lower level, like directly flashing MCUs etc directly at board level?Any ideas before it gets ripped apart would be apricated as I could really use this if it was working.ThanksJohn

author: zrq
author_rank: Frequent Contributor
timestamp: November 29, 2023, 05:21:40 pm
content: Quote from: hobbyelectronics on November 29, 2023, 03:55:18 pmIt would be very unfortunate to make this a parts unit. It certainly seems repairable to me. Check the posts of people fixing 34461As, it should have a similar embedded controller board. See if you can get anything out of the UART as a first step.of course you can give a description of how the machine get bricked and sell it for the broken price, it may be considered more fixable than ones failing in the analog boards by some people and you may find a good price.

author: TheSteve
author_rank: Unknown
timestamp: November 30, 2023, 01:43:44 am
content: I'd connect to the processor UART and see if it does anything.And scrapping it without putting a bunch of work in hurts.Or maybe you want to sell it. I have a working B2901A and a few output modules for parts.

author: hobbyelectronics
author_rank: Regular Contributor
timestamp: November 30, 2023, 08:30:27 am
content: Thanks for your replies.That was going to be my next step. It would be good, but unlikely, to find a schematic for this unit, or even some programming info from Agilent.I was told that Agilent said they could repair it, but would charge around $4000. So it is repairable but like most things, depends on getting the right info and of course even if I was able to flash the MCU and or other parts getting the firmware etc may be a big challenge, if not impossible. I am sure Agilent could help but I was told they were really unhelpful and only offered a repair at this price and also said that it was not a guaranteed fix, so $4K could be spent on just getting back another brick!I will spend more time looking into this further before ripping it apart for spares.ThanksJohn

author: TheSteve
author_rank: Unknown
timestamp: November 30, 2023, 04:05:41 pm
content: There are not even any published calibration docs, never mind service information.

author: hobbyelectronics
author_rank: Regular Contributor
timestamp: December 02, 2023, 09:37:12 am
content: Yeah, I thought as much. Shame really because it will end up being ripped apart for spares etc. When it could actually be repaired.

author: voltsandjolts
author_rank: Unknown
timestamp: December 02, 2023, 10:24:36 am
content: IIRC on the 3446xA/70A DMMs the problem was the front panel circuitry, specifically the FLASH memory for the SPEAR processor. Unfortunately, I don't think swapping front panels with a working unit (for test) is possible. IIRC when a new front panel is fitted, at power on it gets a serial number from the mainboard, which pairs them for life and you can't use it with another unit.AnalogRF managed to rescue a DMM from FLASH corruptionhere.I have a couple of these DMMs and even though they have latest firmware (which has better resilience against FLASH corruption, IIUC) I do wonder whether I should gather some info/memory images through the serial port, as some insurance against possible future problems.

author: analogRF
author_rank: Super Contributor
timestamp: June 05, 2024, 12:26:13 pm
content: Quote from: hobbyelectronics on November 29, 2023, 03:55:18 pmit was definitely repairable.