[Amps] SB-1000 - 3-500Z restoration

Tim _W1WCI kb1gfv at arrl.net
Thu Jan 22 17:39:42 EST 2004


Have a new old SB-1000 with a 3-500Z.  Turns on, lights up, HV ok, but 
tube arcs and fuses blow.
Things checked:
-looks good, nothing looks or smells cooked
-new caps
-diodes test ok
-lights up ok without tube
-transformer windings ok tested at 1000V
Before the tube arcs (I hear it) the tube glows at the base(10-30 
seconds til arc).
Have read about restoring tube by "running low anode voltages and 
positive bias on the grid".  I guess I am asking how to do this?  In the 
amp, out of the amp, what voltage, connected to where?
Any help or advice would be welcomed and I thank all in advance.-Tim



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