Heathkit TC-1 Tube Tester Restoration Part 8
Heathkit TC-1 Tube Tester Restoration Part 8
Part 8: Initial Testing
The moment of truth has arrived. Will it thrive, or go up in smoke??
I plugged the newly reassembled TC-1 into my variac to bring up the voltage slowly. Before powering on the unit, I put the controls in the following positions:
- Set Line: Full CCW
- Filament Voltage: 0.75v
- Lever switches: All in center position
- Type: 1
- Plate: 0 %
Then, I turned on the tube checker. As I raised the voltage, there were no signs of obvious electrical problems, and the Line Voltage indicator slowly crept up.
I found that I could center the Line Level on the meter at any voltage between 107 and 130 vac line voltage.
I checked various filament voltages. With the Line Level centered in the meter, I found that they were all around 10% higher that what was marked. This is not too far off from the state it had arrived in, where filament voltages were high at that time, too. But I figure that if some higher power tubes are tested, they may cause the voltage to drop a bit, so I can live with that.
I went to to test a couple of tubes I had in my junk box. A 12AU7, 12AX7 and 6AU6 all tested good in all sections, and there were no short or open elements found. Many of the tubes that I had in my junkbox are not listed on the roll chart. I’ll go through the procedure for testing those in a future post.
I need to find a knob for the Set Line control and 3 of the lever switches (6, if I want them to all match). While I look for those, I’ll start refinishing the cabinet.
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