05-13-2017, 07:39 PM
Tubes removed...ok then, acceptable.
Still.
1. Establish the field coil and the 27 choke clntinuity.
2. Establish the output xfmr primary continuity, both halves to centertap.
3. Assuming the 71A tubes are good (and if truly bad they can kill res#25 1-2 section or output xfmr)
4. WITHOUT the rectifier power the radio and measure the 80 filament voltage: 5V AC.
5. Measure the rest of the filament voltages: 2.5V
6. Measure the ACbetween the two plates of the 80: see the chart but should be around 500V or more.
7. If all passed, power down, put in all tubes, plug in the speaker, connect the meter on DC to B+ and power up. Wait about a minute for the voltage to rise, see it bo around 300+V or so. See the chart for actual value.
8. Measure plate voltages.
Power down.
Watch for smoke and be prepared to power down.
PPS. Hi voltage (plates, B+) can kill you or put you on your butt: be careful.
PPPS. Make sure the speaker cord is good, no shorts, insulation reajages etc.
Still.
1. Establish the field coil and the 27 choke clntinuity.
2. Establish the output xfmr primary continuity, both halves to centertap.
3. Assuming the 71A tubes are good (and if truly bad they can kill res#25 1-2 section or output xfmr)
4. WITHOUT the rectifier power the radio and measure the 80 filament voltage: 5V AC.
5. Measure the rest of the filament voltages: 2.5V
6. Measure the ACbetween the two plates of the 80: see the chart but should be around 500V or more.
7. If all passed, power down, put in all tubes, plug in the speaker, connect the meter on DC to B+ and power up. Wait about a minute for the voltage to rise, see it bo around 300+V or so. See the chart for actual value.
8. Measure plate voltages.
Power down.
Watch for smoke and be prepared to power down.
PPS. Hi voltage (plates, B+) can kill you or put you on your butt: be careful.
PPPS. Make sure the speaker cord is good, no shorts, insulation reajages etc.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.