08-07-2023, 02:14 PM
Progress 
I made continuity checks on the power transformer, and checked the power switch in the volume control. These always seem to need a clean, such was the case here. With these basics done, I pulled the valves and powered up through the dim bulb tester. No problems indicated, and all voltages from the transformer looked appropriate. Keen to test, I substituted the electrolytics with temporary "tack in" caps, disconnecting the originals. With just the rectifier, B+ came up nicely, no issues on the dim-bulb whatsoever. I replaced all the valves and commenced a careful power-up. Slight hiss and crackle from the speaker, but no stations. Lots of crackling from the wave change switch - a cleanup improved this, but still no stations. As with my previous 6A7 /6A8 set, I suspect the oscillator isn't working thanks to drifted/leaky components. I did inject 480 kHz through the IF, and this, and the audio stage are operating.
Paper cap replacement/restuff and resistor checks next, but this is encouraging stuff.
Ed
I made continuity checks on the power transformer, and checked the power switch in the volume control. These always seem to need a clean, such was the case here. With these basics done, I pulled the valves and powered up through the dim bulb tester. No problems indicated, and all voltages from the transformer looked appropriate. Keen to test, I substituted the electrolytics with temporary "tack in" caps, disconnecting the originals. With just the rectifier, B+ came up nicely, no issues on the dim-bulb whatsoever. I replaced all the valves and commenced a careful power-up. Slight hiss and crackle from the speaker, but no stations. Lots of crackling from the wave change switch - a cleanup improved this, but still no stations. As with my previous 6A7 /6A8 set, I suspect the oscillator isn't working thanks to drifted/leaky components. I did inject 480 kHz through the IF, and this, and the audio stage are operating.
Paper cap replacement/restuff and resistor checks next, but this is encouraging stuff.
Ed
I don't hold with furniture that talks.
