[AMPS] SB220 Grid meter

[Rich Measures]

>sounds to me like the .82 ohm grid meter shunt resistior has assumed a
>different value.  If it becomes an open then the multimetr will try to
>fly across the room (mine did). Suggest you replace the resistor and
>also
>add a 10 ohm 25 watt resistor from point B on the diode board to ground.
>This will protect the multimeter should the .82 ohm shunt open in the
>future.
I do not think this will protect the multimeter. Based on circumstantial 
evidence, the current pulse that opens the 0.82 ohm resistor, R1, can 
exceed 15a.  A good way to protect the meters is with 3a Si diodes.  
Also, there is no reason put the multimeter in grid-I position.  The 
amplifier can not be tuned up with the grid-I meter and Eimac has no 
recommendation or maximum rating for 3-500Z grid current.  
Rich---

R. L. Measures, 805-386-3734, AG6K   


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