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Original Message

Dissecting an Audion Sterling ETSE EL-34 integrated after a loud "Pop!" and smoke (pics & schematic included)

Posted by darkmoebius on April 27, 2006 at 22:42:53:
Looking for some help here.
I was downstairs and could clearly hear the explosion. By the time I got upstairs, there was just smoke rising out of the amp. I unplugged it and let it cool down before venturing in. Man, it really stank up my whole house.
I'm fairly sure that this was not the result any type of AC line surge, etc. because the amp was plugged into a Richard Grey RGPC 400 unit. I don't think, or hope, that it did not blow the output tubes. Doesn't look like it, but I obviously can't plug them in to see.
The schematic says the one blown blue cap attached to each EL-34 socket should have been 400V-47u, but these clearly say Phillips 100V-47u. Maybe that's why they went "Pop!" The charring under this cap is pretty serious and I can't be sure that it didn't hit the copper traces.
- My guess is that bubbled/fried green components next to the blue caps are 510-5W attached to the cathode.
- The one fried black resistor that connects Pins 4&6 reads "105R 1%".
- The potentiometer is a stereo Alps Blue 50k and the black cap on each side is Nover 450V/22uf.
- The 4 big yellow caps say Audion Max SC709 Signal Capacitor 9545D(0.33uf/400V). One of them is coming unwrapped.
- The 4 smaller black caps are Nover 16V/100uf.
- The 2 pairs of sand resistors are 47k/1W that go to the plate.
- The two big caps at the back of the main board are two of the six power supply 220u/250V in the power supple. The other 4 are on the PS board.
- The big white sandcast on the signal and PS board are 100ohm/7W.
Any idea what would blow both channels at the same time? Can the PCB be trusted? Any suggestions for upgrades?
Full board:
Closeup both channels:
Left channel
Right channel:
Power Supply:
Schematic: