Hi,
The calibration cell simply verifies that the meter is 100
microamps and a total of 250 ohms. And it contains the limit resistors
for the leakage test. I wouldn't worry about it.

Incidentally I wouldn't use any silicone lubricants on the
card-reader pins. While the original organic grease has stiffened with
time and needed to be replaced, it was probably carefully selected to
do its job. On the Cardmatics I've repaired, I've used a grease
originally supplied to General Radio by Oak, but I have no idea where
to get more of it. It was described to me by the GR engineer who gave
me some, as "Beacon M325" grease.

73, Alan

For noisy TV tuners back in the 1960s when I was working in a Radio and TV
shop we used Lubriplate white grease that came in a small black and grey
tube that resembled travel toothpaste.We sprayed the wafer switch in the
tuner, rotated several times and then applied a light coating of Lubrplate
with a small stick and rotated several more times. On turret tuners we
cleaned the pads and wipers with contact cleaner on a Qtip and then applied
Lubriplate. This was in Norman, Okla where the humidity played havoc with
tuners making them intermittent and after the treatment we never had call
backs. Somewhere I have a partial tube of this stuff but haven't located it
as yet, so I used DeOxit on the Hickok switch matirix but would have used
Lubriplate if I found it. After about more than 20 moves there's lots of
possiblities where it is. Two local auto parts stores didn't have anything
but silicone grease which I haven't used except as a heat transfer aid on
power transistor heart sinks. I think that Lubriplate would be a good
lubricant/protector unless there's something better that I don't know about.
I'm guessing that there's something better after 40 yeats and would be
interested in what users have used
Now to repair number 2!
73
hank wd5jfr

"Alan Douglas" adouglasatgis.net wrote in message
news
Hi,
The calibration cell simply verifies that the meter is 100
microamps and a total of 250 ohms. And it contains the limit resistors
for the leakage test. I wouldn't worry about it.

Incidentally I wouldn't use any silicone lubricants on the
card-reader pins. While the original organic grease has stiffened with
time and needed to be replaced, it was probably carefully selected to
do its job. On the Cardmatics I've repaired, I've used a grease
originally supplied to General Radio by Oak, but I have no idea where
to get more of it. It was described to me by the GR engineer who gave
me some, as "Beacon M325" grease.

73, Alan