[Amps] SB-220 HV meter on zero

[Catherine James]

I have replaced the back-to-back meter diodes on the Harbach diode meter board (which came with the amp pre-installed, and is not the latest version), replaced the capacitor block, installed a 10 ohm Ohmite glitch resistor, reassembled the amp, and powered up for the first time.

Meter lights come on, fan comes on, tube filaments light up brightly.  But the meters remain stuck on zero.  With the switch set to HV, both meters read zero. I am not expecting to see grid/plate current, but I certainly expect to see a solid HV reading.

I don't know if I have a meter problem, a resistor problem, or an actual lack of HV.  I am particularly concerned because it's difficult to know if the capacitors are fully discharged before opening the case when you have no HV meter reading.  My guess is that it's either the meter(s) or a resistor/diode problem (though I checked all the diodes on the meter board before reassembling) rather than an HV problem.  Is there any easy way to test this with the power off?

I haven't tried to key up the relay or push RF through it.

Thoughts on next steps?  I'm pretty confident the bleeder resistors will drain the caps since all of the caps and resistors in the power supply section are new.  I am **not** particularly eager to do any work with the case open and the 240V power plugged in, much less powered up.

If anyone has a schematic for the metering circuit, not just the meter/diode board but including the meters, that would be helpful.  It's difficult to trace circuits from the Heathkit pictorial manual without a schematic.

73,
Cathy
N5WVR