Hello, I have a Simpson 260-6P VOM which I bought used a
while back. It is in fine physical shape, no internal
corrosion on battery terminals, etc. However, I cannot
get the meter to zero on the Rx1 scale. It continues to read
about 5 ohms with a new battery and a short jumper across
the positive and common terminals. If anyone out there
has Simpson repair experience I have a few questions to
ask that might help me identify the problem, which I suspect
may be in the internal resistor values since all other
functions and ranges seem to work fine. Any help is
appreciated.

Bill

Hi Bill

You mentioned a new battery but be sure it has full voltage and good contacts. The RX1 scale draws a lot of current in this meter and doesn't zero if the battery has a poor contact.

An internal resistor may have changed value but usually it's the battery for RX1 scale.

Norm

: Hello, I have a Simpson 260-6P VOM which I bought used a
: while back. It is in fine physical shape, no internal
: corrosion on battery terminals, etc. However, I cannot
: get the meter to zero on the Rx1 scale. It continues to read
: about 5 ohms with a new battery and a short jumper across
: the positive and common terminals. If anyone out there
: has Simpson repair experience I have a few questions to
: ask that might help me identify the problem, which I suspect
: may be in the internal resistor values since all other
: functions and ranges seem to work fine. Any help is
: appreciated.

: Bill

I would like to thank Don Black and Norm Leal for their assistance on this.
I have started with a fresh battery and measured the voltage
drops around the Rx1 circuit to find that I was dropping
too much across the fuse F1. Upon inspection I found that
someone has substituted a 1/4 amp fuse for what the operator's
manual says should be a 3 amp fast blow. I jumpered around
the fuse (which measures in excess of 4 ohms) and the meter
zeros fine. I will procure a 3 amp fast blow and see what
happens.

Thanks again

: Hi Bill

: You mentioned a new battery but be sure it has full voltage and good contacts. The RX1 scale draws a lot of current in this meter and doesn't zero if the battery has a poor contact.

: An internal resistor may have changed value but usually it's the battery for RX1 scale.

: Norm

: : Hello, I have a Simpson 260-6P VOM which I bought used a
: : while back. It is in fine physical shape, no internal
: : corrosion on battery terminals, etc. However, I cannot
: : get the meter to zero on the Rx1 scale. It continues to read
: : about 5 ohms with a new battery and a short jumper across
: : the positive and common terminals. If anyone out there
: : has Simpson repair experience I have a few questions to
: : ask that might help me identify the problem, which I suspect
: : may be in the internal resistor values since all other
: : functions and ranges seem to work fine. Any help is
: : appreciated.

: : Bill