[volt-nuts] HP 419 (WAS: Fluke 335A versus HP 740B)

[Robert Atkinson]

Hi,
You would have to completly re-design the charging circuit to use lithiums. It is easier to just make up new battery packs. A fairly cheap source of cells would be 10x 2.4V ~600mAH replacement packs for cordless telephones or  4x 6V higher capacity packs sold for RC transmitters and smaller toys.  These come shrink wrapped with lead wires so you don't have to bother about welding tags etc. There may be a space problem with the larger capacity packs. If you are happy with non-floating mains operation, just replace the batteries with two 12V regulated supplies (some powersupply re-arrangement required)
The other one to watch is the bucking supply cell. This was an Hg cell but can be replaced with a good quality alkaline cell in a new holder.

Happy Holidays,
Robert G8RPI.




________________________________
 From: m k <m1k3k1 at hotmail.com>
To: volt-nuts at febo.com 
Sent: Saturday, 22 December 2012, 22:27
Subject: Re: [volt-nuts] HP 419 (WAS: Fluke 335A versus HP 740B)
 

You could replace those 5 cells with two 3-3.6 volt lithium rechargeable cells and get a capacity boost as well.

> Date: Sat, 22 Dec 2012 12:22:03 -0900
> From: cbrown at woods.net
> To: volt-nuts at febo.com
> Subject: Re: [volt-nuts] HP 419 (WAS: Fluke 335A versus HP 740B)
> 
> 
> 
> On 12/16/12 2:34 PM, Charles P. Steinmetz wrote:
> > Christopher wrote:
> > 
> >> The oldest has a oval 3 pin AC connector.
> >> A newer one has a standard IEC socket.
> >> Both of these have 3 battery packs made of some form of coin cell, NiCd,
> >> 225ma, 5 to a stack.
> > 
> > These are what I'm familiar with (I presume you mean 4 packs, not 
> > 3?).  The batteries are Y-5201, long obsolete.
> 
> Yes, 4 not three.
> 
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