[volt-nuts] Fluke 343A part

Dick richiem5683 at gmail.com
Wed Nov 7 19:36:28 UTC 2012

Thanks John -- You are the second one to suggest them. Talon is the deal for sure. I ordered two of these parts. Fluke used them in a lot of gear. 

Have any volt-nuts modified the chopper system of the 343A to reduce parts count and improve stability? Seems like a good place for an LT1150, OPA627 or some such to improve overall performance....

Dick Moore

On Nov 7, 2012, at 4:00 AM, volt-nuts-request at febo.com wrote:

> Message: 1
> Date: Tue, 6 Nov 2012 14:10:16 +0000
> From: John Lofgren <jlofgren at lsr.com>
> To: Discussion of precise voltage measurement <volt-nuts at febo.com>
> Subject: Re: [volt-nuts] Fluke 343A part
> Message-ID:
> 	<5544E52D608067489823B4AED0BB6B570B0B7491 at Exchange2010.lsr.local>
> Content-Type: text/plain; charset="us-ascii"
> Talon Electronics shows a Fluke FP226043 as the replacement for the MEM556C.  They have 48 in stock at $5.12 with no minimum order.
> http://www.talonix.com/shop/item.aspx?itemid=3978
> -John
> -----Original Message-----
> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On Behalf Of Dick
> Sent: Tuesday, November 06, 2012 1:06 AM
> To: volt-nuts at febo.com
> Subject: [volt-nuts] Fluke 343A part
> I picked up a fairly new Fluke 343A and it appears that Q39, MEM556C p-chan. enhancement-mode MOS-FET is shorted. This part seems to be unobtanium unless you are named Romney, Gates, or Walton. Any suggestions on a replacement or an alternative method? This part is the input signal chopper transistor, driven by a multivibrator.

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