PSM-6 (military multimeter) battery replacement

[Michael]

Calling all military and ex-military electronics weenies.....
Remember the "boat anchor" PSM-6 multimeter? So heavy that it should
have come with a 'scope cart, but RUGGED. The test equipment we loved
to hate.

I picked up one of these beasties, surplus, in the 80's and have used it
continuously ever since. The battery died a while ago, so can't measure
resistance. The battery in my particular meter might not be the correct
one. It's marked BA-1085/U and is dual voltage with wire leads.
Cylindrical, about 11/16" in diameter and 4 1/2" long. 1.3v and 13.0v

I'd like to replace with separate, easier to get batteries. Anyone work
out - or know of - such a modification?

Michael

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

Calling all military and ex-military electronics weenies.....
Remember the "boat anchor" PSM-6 multimeter? So heavy that it should
have come with a 'scope cart, but RUGGED. The test equipment we loved
to hate.

I picked up one of these beasties, surplus, in the 80's and have used it
continuously ever since. The battery died a while ago, so can't measure
resistance. The battery in my particular meter might not be the correct
one. It's marked BA-1085/U and is dual voltage with wire leads.
Cylindrical, about 11/16" in diameter and 4 1/2" long. 1.3v and 13.0v

I'd like to replace with separate, easier to get batteries. Anyone work
out - or know of - such a modification?

Michael

Judging by the voltages, I'd say that this is a battery consisting of
mercury cells. They are now banned because of the mercury, so you
really should consider finding an alternative. I would use a couple AA
cells and a V boost circuit to get the 3V up to 13V, and then use a
regulator to get the 1.3V.

 

[Michael]

Judging by the voltages, I'd say that this is a battery consisting of
mercury cells. They are now banned because of the mercury, so you
really should consider finding an alternative. I would use a couple AA
cells and a V boost circuit to get the 3V up to 13V, and then use a
regulator to get the 1.3V.

Thanks for your input, Watson. I'm pretty sure the spent battery isn't
the proper one for this meter; it was hardwired in. Voltages are close
enough to measure resistance OK though. And it does fit into the
battery bracket. There is _very_ little extra space inside the meter
case, restricting the sizes and amounts of extra stuff any mod. might
require.

The PSM-6 is a rugged workhorse, thousands of guys trained on it, and
thousands of these meters are in the civilian market. I was hoping that
at least one owner who has done - or knows of - a mod. would see my
post.

Michael