by Jeff Gehring
1. Visually verify that the bridge rectifier is installed such that the angled corner of the package is closest to the control side of the chassis, and that the two red leads from the PT connect to the two middle leads of the rectifier package. Ensure that these connections–and any other board connections, for that matter–do NOT extend so far thru the eyelets as to make contact with the chassis!
2. With your ohmmeter, connect the black lead to the bottom lead of the rectifier package (closest to the tube socket side of the chassis). With the other lead, ensure continuity between the low side of the filter caps, C1 thru C5 and the rectifier bottom lead.
3. Leaving the ohmmeter black lead connected to the rectifier grounded leg, take resistance readings from the positive side of the filter caps, C1 thru C5. These should be high readings, in the hundreds of kohms or megohms.
4. Leaving the ohmmeter black lead connected to ground as before, measure resistance from pins 4 & 5 (which should be tied together) on the V1 socket. Then measure resistance from the V1 socket pin 9 to ground. Both readings should be the same and if you have grounded the center tap of the filament buss, this should read near zero ohms. If you have returned the filament center tap to the 6V6 cathode, it should read 1k ohms.
5. Check for continuity through both sides of your filament buss wiring from point of entry from the PT to the last tube socket, with no tubes plugged in.
6. Check for continuity from the top leg (the positive output) of the rectifier to the positive side of C1 and C3.
7. Visually inspect your AC input wiring–no shorts to the chassis, correct fuse is loaded, etc. Their should be NO continuity to ground from either the hot or the neutral prong of the AC plug to chassis ground with the power switch set in the on position. Resistance from the hot prong to the neutral prong on the AC plug, with the power switch in the on position (measuring thru the PT primary) should be approx 12 ohms or so. Make sure all of the PT wires are properly terminated.