EEVblog Electronics Community Forum

Electronics => Repair => Topic started by: sabahan on October 27, 2016, 07:44:54 am

Title: HP34401a screen repair
Post by: sabahan on October 27, 2016, 07:44:54 am

I bought a worn HP34401a with the display not displayed in full,the florescent some a not lid,I manage to get a replacement from eBay but how to I remove the old one from the meter,I read the instruction online ,the instruction just mention remove the screen but did not mention how,anyone have experience?please help

Title: Re: HP34401a screen repair
Post by: HighVoltage on October 27, 2016, 07:49:35 am

Welcome to the forum

Download the 34401A service guide. On page 151 you will find an illustration of how to remove the front panel. Once you have removed the front panel, the rest is almost self explanatory to exchange the front panel PCB.

Title: Re: HP34401a screen repair
Post by: bitseeker on October 28, 2016, 12:56:11 am

Hi sabahan,

Welcome to the forum. Did you buy a replacement front panel PCB, on which a VFD module is already mounted, or just the VFD module (i.e., only the glass display)?

When you say "remove the screen" are you referring to (1) removing the front panel from the chassis, (2) removing the front panel PCB from the front panel, or (3) removing the VFD module from the front panel PCB?

Title: Re: HP34401a screen repair
Post by: coldframe on October 28, 2016, 02:17:34 am

Hello sabahan

VFD(Vacuum Fluorescent Display) is irrepairable part.
Replace, For now this is the best way to go

Have a read of this article
VFD display for HP 34401a multimeter wanted
https://www.eevblog.com/forum/buysellwanted/vfd-display-for-hp-34401a-multimeter-wanted/msg197353/#msg197353 (https://www.eevblog.com/forum/buysellwanted/vfd-display-for-hp-34401a-multimeter-wanted/msg197353/#msg197353)

coldframe.

Title: Re: HP34401a screen repair
Post by: BFX on October 28, 2016, 08:28:12 am

Replace:
http://www.ebay.com/itm/HP-AGILENT-34401A-Display-NEW-/151840490023 (http://www.ebay.com/itm/HP-AGILENT-34401A-Display-NEW-/151840490023)

Title: Re: HP34401a screen repair
Post by: eb4eqa on October 28, 2016, 01:45:32 pm

That VFD module from eBay does work and it is new, but it is not original. I've installed one and it is not nearly as bright as the original one. Only way to go if you have a severely dim one or if do not have one at all...

Roberto EB4EQA