Fluke 335A versus HP 740B
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.
The newest 419 is different. Different battery holder, and uses 4 packs
of 5 1/3AA cells. These are not common, but are not that hard to get.
Now, converting an older unit would not be hard. The only thing diff is
the mount and the packs themselves.
shopping for 20 good tabbed 1/3AA cells. Solder 5, inline
shrinktube, repeat 4 more times and done.
Thanks very much for this information!
Yesterday I tried to post a message with a drawing of the older
battery installation, but it was rejected as oversize.
A very good US source for the best quality NiCd cells is SR Batteries
http://www.srbatteries.com/. He can also build packs with welded
straps and tabs (soldering directly to the cell almost always
substantially reduces the life of NiCds, no matter how careful you
are). I do not know if he can supply 1/3AA cells, but it is worth
checking. (No connection other than satisfied customer.)
Best regards,
Charles
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.
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@woods.net
To: volt-nuts@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.
volt-nuts mailing list -- volt-nuts@febo.com
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and follow the instructions there.
Hi m,
From: "m k" m1k3k1@hotmail.com
You could replace those 5 cells with two 3-3.6 volt lithium rechargeable cells and get a capacity boost as well.
Is it fire proof?
Bye,
Jean-Louis
The lithium aren't a big problem as long as you have a proper balancing charging circuit.
Obviously you should not use any built in charging circuit that is not designed for use with the chemistry of the new cells.
On Dec 22, 2012, at 14:41, "Jean-Louis Noel" jln@stben.net wrote:
Hi m,
From: "m k" m1k3k1@hotmail.com
You could replace those 5 cells with two 3-3.6 volt lithium rechargeable cells and get a capacity boost as well.
Is it fire proof?
Bye,
Jean-Louis
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Hi Peter,
From: "Peter Loron" peterl@standingwave.org
Obviously you should not use any built in charging circuit that is not designed for use with
the chemistry of the new cells.
Obviously the old HP circuit is not designed to feed lithium batteries as MK proposed.
I use three 9V batteries in serial with the battery in the middle transformed.
You remove 1 element and connect a wire in the middle.
http://www.stben.net/hp/DSCN0644.JPG
http://www.stben.net/hp/DSCN0645.JPG
http://www.stben.net/hp/DSCN0646.JPG
http://www.stben.net/hp/DSCN0647.JPG
http://www.stben.net/hp/DSCN0648.JPG
http://www.stben.net/hp/DSCN0649.JPG
http://www.stben.net/hp/DSCN0650.JPG
Bye,
Jean-Louis
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@hotmail.com
To: volt-nuts@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@woods.net
To: volt-nuts@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.
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.