VFD display for HP 34401a multimeter wanted - Page 1
Forum section: electronics / general

author: John_L
author_rank: Contributor
timestamp: February 12, 2013, 11:24:18 pm
content: Looking for new Fluorescent display for one of my older HP 34401 that is gone fairly dim.On ebay only one source from China for about US$105 including shipping.http://www.ebay.com/itm/HP-AGILENT-34401A-Display-/251169866676?pt=LH_DefaultDomain_0&hash=item3a7ae403b4.This is the description of the item.""New other (see details): A new, unused item with absolutely no signs of wear. The item may be missing the original packaging, or in the original packaging but not sealed. The item may be a factory second or a new, unused item with defects""I don't like the sound of factory second and unused item with defects, also don't know the origin of the product.Can anyone recommend any other source for the display?CheersJohn

author: free_electron
author_rank: Super Contributor
timestamp: February 13, 2013, 12:50:11 am
content: that's your only chance. agilent doesn't sell them, only the complete fornt panels and they're pricey ( 300$ )

author: John_L
author_rank: Contributor
timestamp: March 01, 2013, 11:41:09 pm
content: Replaced VF display withhttp://www.ebay.com.au/itm/HP-AGILENT-34401A-Display-/251169866676?pt=LH_DefaultDomain_0&hash=item3a7ae403b4.Works fine and I can't see any difference in quality or brightness when comparing to my other newer Agilent 34401A meter.Actual part no. is SAMSUNG SSVD INB-12MM52T.

author: nukie
author_rank: Frequent Contributor
timestamp: March 02, 2013, 11:57:10 pm
content: The Chinese clone is $45 not including shipping, don't know about operating hours, better get the mention Samsung.

author: nukie
author_rank: Frequent Contributor
timestamp: March 03, 2013, 12:09:33 am
content: Sorry about my crap phonecam, haven't got time to install it, its as bright as the original display, according to the seller.

author: schopi68
author_rank: Regular Contributor
timestamp: December 03, 2014, 09:23:49 am
content: Quote from: free_electron on February 13, 2013, 12:50:11 amWell, including tax fee etc. I paid ~85 Euro for the Chinese Ebay-Version.Keysight sells the front panel (VFD mounted on PCB for replacement) for ~100 Euro (inkl sales tax) here in Germany. According to the Keysight part Number finder is the US-Price at 93,52$.(I am writing this as i went the wrong way first - i bought the ebay-Version which destroyed the transformer of my 34401a because i had overseen that there is a electrical connection on the outer side of the chinese vfd which builts a short to the esd-shield).

author: HighVoltage
author_rank: Super Contributor
timestamp: December 03, 2014, 10:48:41 am
content: I also bought a new original PCB with VFD installed from Agilent Germany, since I did not trust the China version on ebay.Interestingly the new VFD from Agilent is even brighter than the VFD of a relative new 34401A. The cost was a little over Euro 100 including shipping and VAT.

author: caall99
author_rank: Regular Contributor
timestamp: December 03, 2014, 03:07:58 pm
content: I have a new 34401A VFD that i purchased a while ago with the intent of installing into one of my meters. I don't think i will have a use for it anymore. New in box. You can PM me if you are interested.

author: on4top
author_rank: Regular Contributor
timestamp: December 29, 2016, 02:14:19 am
content: Got one from china this week ... but dodgy ..I was well packed .. but 2 wires are broken inside ..http://www.benl.ebay.be/itm/1PCS-NEW-HP-AGILENT-34401A-Display-VFD-vacuum-Fluorescence-Display-CCX-/181666132321?hash=item2a4c253161:g:H9AAAOSwstxU3Z2lContact seller .. he send me new one or refund me ..I asked for new one .. hope thisone wil be ok ?... seem to be verry fragile to send .. it was packed verry well in bubbel wrap and a big box ..

author: SvanGool
author_rank: Regular Contributor
timestamp: December 29, 2016, 09:36:02 am
content: I got one coming in from the same company, fingers crossed.While installing and testing this one, did you have the previous mentionedQuote from: schopi68problem?

author: on4top
author_rank: Regular Contributor
timestamp: December 29, 2016, 10:08:18 am
content: esd-shield is probably the 2 copper strips above and botton of the VFD ?i did not installed them back yet ...tested w/o them..good to know ... and check ..when i get new one ..

author: SvanGool
author_rank: Regular Contributor
timestamp: January 02, 2017, 11:36:31 pm
content: I received the new display today,I de-soldered the original one and soldered in the new one, that kept me busy a couple of hours. Although it was not an exact (maybe just too much tolerances) fit, I had to bend the studs of the shield a bit, it is working.I think the "ESD-shield" is indeed the EMI-shield around the display. I did not connect anything else than the pins on the bottom side, so I made no contact to the EMI-shield with one of the unused pads at the side of the new display, which the old one didn't have.

author: schopi68
author_rank: Regular Contributor
timestamp: January 27, 2017, 11:15:57 am
content: Quote from: SvanGool on January 02, 2017, 11:36:31 pmReferring to the service guide the part mentioned is A2 M600, documented as "Shield-ESD".But technically you're right, it is an EMI-shield (as noted i.e. in this Patent:http://www.freepatentsonline.com/7515219.pdf)(and leaving it out may disrupt the emi-specifications of the device)

author: janoc
author_rank: Super Contributor
timestamp: January 27, 2017, 05:20:48 pm
content: I have been solving this exact issue just recently.I have ordered a replacement from this vendor last October (doesn't seem to have anything on sale now, but it is Chinese New Year, so check in a week or two):http://www.ebay.fr/usr/shop*forpartsThe display has arrived fine, well packed and works like the original. If you decide to get one, be careful to check for exposed contacts on the sides. The original VFD has them insulated. I have put there some electrical tape to prevent them from touching the metal shielding frame holding the VFD and shorting out the power supply. I think that is the issue @schopi68 was referring to.The hardest part of the repair is probably disassembling the meter - even with the service guide it can be a bit non-obvious how to take the chassis apart (do not pullat the ribbon cables/connectors, one has topushthe connector down to release it!). Desoldering the old VFD and putting in the new one has been perhaps 10 minutes of work tops.

author: bitseeker
author_rank: Super Contributor
timestamp: January 28, 2017, 03:40:53 am
content: Yes, disassembly is rather non-obvious and the manual's description isn't very obvious until after you succeed. Thanks for the warning about the exposed contacts.

author: ian.ameline
author_rank: Regular Contributor
timestamp: March 27, 2018, 08:33:13 pm
content: Keysight is selling the board assembly (with display) for $138 US. They have 8 left in stock. (It was 9 until I ordered one.)Part #34401-65522

author: bitseeker
author_rank: Super Contributor
timestamp: March 27, 2018, 09:10:47 pm
content: Be sure to check with Keysight that your DMM is compatible. Early 34401A models would not work with newer displays last I heard.

author: ian.ameline
author_rank: Regular Contributor
timestamp: March 30, 2018, 01:11:40 pm
content: Quote from: bitseeker on March 27, 2018, 09:10:47 pmI gave them my serial number -- it works fine. It's a revision 3 display :

author: bitseeker
author_rank: Super Contributor
timestamp: March 31, 2018, 01:19:53 am
content: Yes, you have the newer DMM (black LO jacks). Looks great!

author: ian.ameline
author_rank: Regular Contributor
timestamp: March 31, 2018, 04:41:58 am
content: Quote from: bitseeker on March 31, 2018, 01:19:53 amDate codes & stamps inside show it was manufactured at the beginning of November, 1999.With the new display board, it looks and acts like new -- nicely aged reference, calibration from Keysight within the last 12 months. And all for around USD $380 (including the new display)

author: HighVoltage
author_rank: Super Contributor
timestamp: March 31, 2018, 09:13:01 am
content: Quote from: ian.ameline on March 31, 2018, 04:41:58 amCongratulations on your success.That is indeed a good deal for a good working 34401AIn Europe, the good working units go for $ 500 or more.

author: janoc
author_rank: Super Contributor
timestamp: March 31, 2018, 12:33:49 pm
content: Quote from: HighVoltage on March 31, 2018, 09:13:01 amGot mine for 257 euro in 2016, delivered. Including a still valid cal :-p It was working perfectly fine, just needed some grime cleaned off, the rear plastic bezel was cracked in two places (easily fixed with a drop of glue) and replacing the dim VFD (the Chinese one works fine). I have also bought the bumper and handle kit for it because it didn't have them (it came from a rack).But yes, I wrote to the eBay seller afterwards that they are crazy to sell them for such price. And he actually offered me a second oneCome to think of it, should have bought it too and resold it.

author: charlyd
author_rank: Frequent Contributor
timestamp: April 03, 2018, 09:50:15 pm
content: i got one for my 34401a from the same adress 1/2 year ago.. works great uuuh yes $105 total. but after a week you dont remember anymore ;-)