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Re: [Amps] SB220 Meter blown

Subject: Re: [Amps] SB220 Meter blown
Date: Sat, 16 May 2020 09:24:28 -0500
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And back when the SB220 was built, meters were $3 each.

Today, if you want to protect the appearance and functionality
of your GG Amp's meters, I'd suggest adding an op-amp interface
to prevent high currents from damaging the movement.


Quoting Jim <>:


.6 or .7 or slightly more during an "event" volts is still enough to blow up the meter.

Jim W7RY

On 5/15/2020 4:08 PM, Adrian wrote:
from ;

"6. Meter damage can be avoided by connecting two, ordinary = or >1A, any PIV, silicon rectifiers across the terminals on each meter. The two diode arrows should point in opposite directions."

On 16/5/20 1:10 am, Artek Manuals wrote:
I am resurrecting a SB220 that had an apparent classic Grid/plate short event. One of casualties appears to be the right hand meter movement. This is the one for Grid Current and HV. I am pretty far into it and the meter movement measures open , the internal shunt resistor is blackened ( and open?)

Anyone got a surplus movement from a parted out unit? Nothing found on evil-bay at the moment

Dave NR1DX

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