[Amps] grid current issue

[Roy]

About:


"Your grid shunt resistor is open


In a message dated 8/31/2009 2:55:12 P.M. Pacific Daylight Time,
kb8nnu at yahoo.com writes:

Hello  all...

I have been working on restoring an LK-500 NT to operating  condition and
it has a funny grid current issue.  When I switch the meter  switch over on
the front to measure the  grid current, the meter goes  negative...???? 
This
happens when the amp is in RX.

I'm  puzzled....any help would be  appreciated."


Or, you have an internal short in a tube -- 3-500Zs are infamous for that, 
especially when no fil in-rush protection is used.

73,  Roy   K6XK