Build Your Own Clone Message Board

Completed my amp this evening. Really had a lot of fun with this build. Until...

I fired it up for the first time with no tubes and a light bulb current limiter because I can't stand the sound of smoke alarms.

25W bulb, steady on. No indicator lamp on the amp. Hmmm. AC voltage at the input was pulled down to about 11VAC. Something isn't right.

Check for obvious shorts, etc. Nothing.

After looking at the schematic and layout, there really isn't much it could be.

Disconnected the indicator. Still steady on the 25W bulb. Uh oh.
Reconnected the indicator and disconnected the PT primary. Indicator is happily glowing.

Measured 3.5 ohms across the PT primary. (Black to Black/White) That sure sounds like a bad PT to me. Am I wrong? I would love to be wrong... It would mean that I don't have to wait for another PT.

Thoughts?

Cheers,
Dave

Short version: Bad heater wiring. Passed a dozen or more visual inspections.

The kit didn't have enough wire for me to run the heater wiring the way I wanted, and I usually use two colors. So, I used some wire I had on hand. It was junk. The insulation had melted where the two sides had crossed tightly. It looked great until I pulled it apart.

All is good now. Installed rectifier, still good. Going back to bed and will finish tests in the morning!