...perhaps it might be worth considering the addition of a pair of diodes
connected in antiparallel across meter. We used to do this in the past and
it was cheap insurance for the meter!
If the voltage drop needed is higher than what a single diode can handle,
you can connect 2 or more in series and connect two strings in 69 fashion.
They saved the day for me more than once (Triplett meters were never
cheap!).
73 and all the best:
Alex 4Z5KS
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of donroden@hiwaay.net
Sent: Wednesday, September 02, 2009 5:47 PM
To: amps@contesting.com
Subject: Re: [Amps] LK-500 Metering
If a shunt opens across a meter, ALL the current goes through the meter.
( smoke and flames )
Don WA4NPL
Quoting "Edwin Karl" <edk0kl@centurytel.net>:
>
> Look in the amplifier for a board that is in the front left corner of the
> cabinet.
> You will find 2- 5 watt resistors. One is for the Grid Current metering,
the
> second
> is for the plate current, each are .3 ohms, one is plate metering shunt,
the
> other
> is grid shunt.
>
> The meters are actually configured as voltmeters and measure drop across
the
> shunts,
> in that way when the shunt opens a short flame does not appear in the
meter
> case. The
> grid meter is in the HV return lead (- volts) that's why the meter is
acting
> as it is.
>
> Parts are available from Mouser.
>
> Good Luck, we're all counting on you.
>
> 73!
>
> ed K0KL
>
> _______________________________________________
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> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
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