Low power problem..100w

[ThunderOne]

I thought that you built a Metro kit like mine. So you got your parts from different sources and assembled them. At least you didn't pay too much for that defective OT and you managed to zero in on it. My situation is different. I still think that my amp's output is not what it should be but it's not as low as I perceived it at first and the output I get is really great sounding. Could a damaged or defective OT behave that way? I don't know and until I can find a way to be sure, I'll refrain from any presumption. At this point, a well laid out troubleshooting guide would be a great help.

[6ringing]

Well here's what I found and used to diagnose my OT problem, real simple to do:

Simple Tests
Unplug the amp and drain the capacitors before you start. Do not remove the transformer from the amplifier before you start. Remove the output and rectifier tubes.
Identify which wires are which by circuit connection. The primary will have two (single ended), three (push pull, or very rarely single ended with ultra linear tap), or five (push pull with ultralinear taps) leads. Noting which leads connect to the B+ line, measure the resistance from the B+ lead to each plate of the output tube(s). Write the resistance reading down. Measure the other side if it's puah pull. Plate windings are almost always in the tens to a few hundred ohms of resistance. A reading much over 1K is pretty sure sign that the winding is burned open. If it's open, the transformer is dead. [There are ways to fix "slightly-dead" transformers, but this is extremely risky, and probably doomed to failure. I'm not going to write down how. Don't waste your time.]
While you're at it, measure the resistance of every lead to the chassis. This reading should be very high, hundreds of K or preferably megohms. A low reading here indicates a short to the transformer core - again, dead transformer.
Do a similar test on the secondaries - look for open windings, or shorts to the core. Finally, test for the resistance from primary to secondary. A low value, under a few K indicates an internal short, and a dead transformer.
If the transformer fails any of the simple test, it's dead. Replace it. If it passes all of the simple tests, it may still have an internal short Sometimes a primary will have enough resistance that the transformer does not burn up or burn the wires in two , but will just bog down, have low power and sound bad. If you suspect that is the case and you don't have the skills to do the advanced tests, take it to a competent tech.

[demonufo]

OT's don't always sound bad when they go. They often go real clean and quiet, or more dirty and quiet (like my 4104 when it went). My amp sounded great when it went, just real quiet. Like, flat out and still able to talk loudly above it, quiet.

[ThunderOne]

Thanks for the info, guys. I'll run all available ways of testing my OT. In my case, the amp sounds the way it should, really great, but just not as loud as a 100W should. I measured the AC voltage at the output with a signal (averaged AC squared divided by resistance) and got 12.5W!

[6ringing]

That's exactly like mine went, sounded great! Just lower volume. It was kind a a good thing actually...but I do need a 100 watter!