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Products => Test Equipment => Topic started by: lowimpedance on September 10, 2012, 12:44:18 am

Title: HP3456a service notes, for owners info!.
Post by: lowimpedance on September 10, 2012, 12:44:18 am

 Just repaired a number of 3456a's at work, (yes a few still being used!). Although most have been replaced with the 3458.
Any way I came across some HP service notes tucked away in one of the old handbooks, so I have attached them here for the reference of owners of these Voltmeters.
They may be of some use, or you may have them already!. There are probably more but I cannot find them on line, (found reference to number 16 in a bench brief, but not the actual note  :().
Also I took a few pictures and attach those as well.
Quick note to those owners that might have "orange sleeved' jacketed electrolytic cap's in the power supply PCB, even if your meter passes all self tests, I would recommend you replace them  asap. While checking the meters at work I had one unit pass its tests but inspection of the PS PCB showed corrosion at the lead of one of the orange electro's.
Cheers
LowZ

Title: Re: HP3456a service notes, for owners info!.
Post by: saturation on September 10, 2012, 03:32:08 pm

Thanks a bunch for this, lowZ, they're great!

Title: Re: HP3456a service notes, for owners info!.
Post by: MetraCollector on September 10, 2012, 09:21:53 pm

This voltmeter is a piece of art !

I would very like to own some. Is there any possibility to get this machine in middle Europe for reasonable price ?
I think this will be very educational for me and would be honour for me owning this device :)

Title: Re: HP3456a service notes, for owners info!.
Post by: quantom_B on September 27, 2012, 10:17:06 pm

Have 3456a here with downed power supply.  dont get 5V or 33V, but all other voltages look good.  Have a pdf of scanned Operating and Service Manual (only one I can find on net), but it only shows schematic of p.s., but not the table for part numbers of this board -it lists the board as A10, Inguard Power Supply, 03456-66510.  I find this odd as all the other boards are shown and all have a table with part numbers.  Wondering if someone skipped a page while scanning. Do you by chance have documentation that shows these part numbers?

Thanks

Title: Re: HP3456a service notes, for owners info!.
Post by: lowimpedance on September 28, 2012, 05:18:25 am

Are you referring to the replaceable parts list or the table near the schematic and pcb picture??.
Just checked a manual (a real one, not a PDF!) and there is no table at the schematic page for the PS A10
 U1 = 7805
 U2 = 7815
 U3 = 7915
 U4 = lm337
 complex cct here!! :D.
Check C5, most likely stuffed. And since your 33v rail is referred to the 5v it will likely be fixed too (unless c7 is dry).
(dont forget to check your other 'electro's. ' , better still just replace the lot.).

LowZ

Title: Re: HP3456a service notes, for owners info!.
Post by: quantom_B on September 28, 2012, 03:11:43 pm

Many thanks for the great info LowZ !!

qB

Title: Re: HP3456a service notes, for owners info!.
Post by: don.r on February 24, 2018, 11:50:33 pm

lowimpedance,

You don't happen to have a copy of service note 3456A-12 ... aka the fanless mod?