I think the Mark 1 used a single meter for all functions including plate
current, grid current and plate voltage. If so, there's some fancy
switching going on, there. Without the switch and the combination of shunt
(parallel) resistors for plate & grid current, and a multiplier (series)
resistor for HV, it's likely the meter itself is a 1mA movement, or
something thereabouts, and if disconnected from amplifier wiring and tested
by itself, you can probably get it to "pin" using an Rx10 VOM with good
batteries.
How did you measure continuity? Across the meter probably looks like a dead
short when it's switched to the Ip scale, because the shunt resistor would
have very small resistance (milliohms). Across the meter should appear a
much higher resistance when it's switched to the HV (Ep) scale, as there's
likely a whole lot of resistance in series, and nothing in parallel, with
it.
WB2WIK/6
"If everything seems under control, you're just not going fast enough." -
Mario Andretti
> -----Original Message-----
> From: Bill Smith [SMTP:ko4nrbs@yahoo.com]
> Sent: Monday, June 03, 2002 6:29 AM
> To: amps@contesting.com
> Subject: [Amps] Swan Mark 1 Meter Problem
>
> My Mark 1 meter will not indicate anything at all. I
> have traced all the wiring throughout and did
> continuity checks but can't find anything wrong. How
> can I test the meter without damaging the movement? I
> did use an ohm meter set on it's lowest scale and got
> the meter's hand to go up.
> 73,
> Bill
>
> =====
> Bill Smith KO4NR
>
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