[Amps] AL-1200 Grid Current - negative?

R.Measures r at somis.org
Mon Nov 10 03:30:25 EST 2003



>Amps folks -
>
>Ok, I removed the tube and the meter still went negative.  I checked the 
>filament connections with the tube out, nothing is shorted to ground.
>
>I was suspect of the metering circuit itself.  The left multi-function meter 
>measured 300 ohms across the terminals, the right grid meter measured 15k. 
>The parts list indicates both meters are 300 ohm 1ma.
>
>I took the grid meter apart, it has a component (a precision resister, I 
>assume) in series with each internal meter movement lead.  One measured 100 
>ohms, the other about 15k.

**  What is the marked resistance of the 15k-ohm R?  Is the meter 
movement associated with it still good?
>
>I am pretty clueless about this, and Im at a loss as to why a 100ohm 
>resister would become 15k, but perhaps this is my problem.

**  Sounds like it.  

cheers,  Dana
>
>
>Dana Roode wrote:
>> What does it mean when you power up an AL-1200 and the grid current 
>> meter pins negative (no drive power supplied)?
>> 
>>   Dana
>> 
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>> 
>
>
>_______________________________________________
>Amps mailing list
>Amps at contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
>


More information about the Amps mailing list