34401A Replacement Transformer - Page 1
Forum section: electronics / repair

author: CrazyTiger
author_rank: Regular Contributor
timestamp: April 11, 2022, 03:15:13 am
content: Hi,I have two 34401A with defective transformer, someone tried injecting 240V to the meters set at 110V. Now looking for replacement, keysight no longer sells them, with details as link below:https://www.keysight.com/my/partDetail/34401-87901Best part they are selling eeprom and smd resistors, capacitors and whatnot which requires soldering, but a simple user replaceable transformer requires keysight expertise for replacement.Anyway I found lots of China made equivalent transformers on Ebay, has anyone tried them?Another keysight joke, fuse requires keysight expertise as wellhttps://www.keysight.com/my/partDetail/2110-0780Thank You

author: floobydust
author_rank: Super Contributor
timestamp: April 11, 2022, 04:13:35 am
content: How far did the roasting of the transformer go? It might have a thermal fuse that popped (on the common/neutral leg) and worth a dig to replace it. If there is continuity between primary to the electrostatic shield, then I'm afraid it's dead Jim.Search for the original part number Tranex 9100-4972 is better, but I also see listed for the 34401A Tranex 9100-5608 but is for 34970A I believe.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 11, 2022, 10:43:34 am
content: some transformers can be found on fleabay some are originals some are clones of the originals normally in the 70-80$ usd rangeBut for mine i had the chance to buy an originalThe only test you could do, is buy one and test the output voltages if they are in the needed range / values ?? on ebay you will have some warranty or a possible claim if they are not correct ?

author: HighVoltage
author_rank: Super Contributor
timestamp: April 11, 2022, 11:39:08 am
content: I would contact Keysight directly. Sometimes they have stock on items that are not listed officially.

author: IanJ
author_rank: Unknown
timestamp: April 11, 2022, 09:59:54 pm
content: Keysight are pretty good at replying to parts enquiries......can take them a couple of weeks to reply though.Ian.

author: TaylorD93
author_rank: Regular Contributor
timestamp: April 11, 2022, 11:29:46 pm
content: I can understand the fuse.If a fuse pops there usually (not always) a reason why, which may need investigating further. Not all companies are willing to just open up and repair their own instruments. So Keysight are obviously going to be on the side of caution and say "oh yes you need to send it back to us to give it a clean bill of health once we have replaced the fuse"With the transformer itself, as Ian said, drop them an email. They've never not got back to me, just slow at times. They maybe able to do a surcharge/PX on your old transformer etc.But as so many 34401A were built, id be very surprised if they have run out of spares that quickly.

author: CrazyTiger
author_rank: Regular Contributor
timestamp: April 14, 2022, 12:08:26 am
content: Update:I have done all the options suggested here.1. Ordered 1 China made transformer, to see the performance2. Dropped an email to Keysight, awaiting reply3. Will be operating the defective transformer to see if the thermal fuse popped inside.So hopefully in 2 weeks time, I can update how it went