Yesterday I took off from the shelf the nice Dynaco ST-35 that I bought several months ago from ebay to give it a run. It was restored from the seller that replaced the two printed circuit boards and installed also an Audio Sound Lab cap board to replace the old can cap. The amp played very good, even though he had put Tesla tubes and 715P (not 716P) caps on the tube boards. Then I decided to replace at least the 6BQ5's with some better quality tubes that I had at hand. It sounded well, better than before, so I decided to let the new tubes in. And now I did my dumb action, I tried to put again the cage on the amp without turning it off. To make a long story short, I don't know where the cage touched when I tried to put it into place (probably something on a board) but I saw a spark, heard a pop and a channel died. One speaker continued to play music while the other didn't. All the tubes still lighted. The fuse didn't blow. Then I checked the voltages on the 4 EL84 and they were good. I wasn't able to read the voltages on the ECC832 by checking the numbered ponts under the printed circuit board (I don't know if I did this in the right way).
The first thing I feared was to have blown OPT? So I checked the impedance and they were still good (less than 200 ohm on the primary side and less than 2 ohm on the secondaries) and were about the same on both OPTs so these seems save.
What other should I check to try to understand what happened? I am a newbie when it comes to electronics troubleshooting so I would need a step-by-step guidance.
Any help would be very appreciated.
Thank you very very much.
P.S.Please don't insult me for my stupid action, I already did it myself for acting like a moron