HELP!!! RM100 powers up, but no sound on 'PLAY'. GUT PICS

[skunky_funk]

I just installed new RUBY EL34BHTs and biased each tube for 37mVDC. It was working and suddenly, I heard a small 'pop' sound. Then, no sound at all.

I replaced two of the HT fuses, which blew. But even after, there is no sound as yet. What is wrong??? Don't tell me it's my OT.

 

[okstrat]

There are several fuses in the chassis, I'd check those. Go into the gigmods part of the forum, I have a thread with pics that show you where all the internal fuses are. Check them with a meter, not by eye.

Pete

 

[6stringgrind]

Are your tubes lighting up when you turn the amp on? If not, it's probably the fuse inside the chassis for the tubes. I have EL34s in my amp, and was having trouble with a fuse blowing repeatedly. Jeff from Egnater told me to put a 15 amp slo-blo in there (the original is a 10 amp) and so far that's working.

A word of caution: Don't pull the chassis out if you don't know what you're doing. LETHAL voltages are in there. If you touch the wrong thing, you're toast.

 

[skunky_funk]

Special Thanks to okstrat for the invaluable info on the fuse location thread at the Gigmod forum.

Anyway, here's a pic from that forum:

I checked out the internal fuses and turns out Fuse 4 and 5 were busted. They both are 1.6A in rating. The local electronics shop had no 1.6A fuses available so, in my desperation, I went for 2A fuses. :?

I reinstalled the old tubes in my amp... 2 =C= EL34s (inner pair) and 2 JJ E34Ls (outer pair). Biased the =C='s for 35mV, and the JJs for 41.5mV.

For a while, it played like butter. So I thought it was great.

After a few minutes, I tried cranking up the amp. Whenever I strummed a chord, the 2 leftmost tubes (V1A AND V2A) seemed to glow (like strobes) more whenever I made a strum compared to the rightmost ones (V3A and V4A). And when I maxed out the volume, the same pop sound happened, only that I saw a spark somewhere and a burnt smell.

Turns out, the brown wire connected to the OT with a spade connector has a bad burn on the PCB. Check the pics:

So I tried replacing the 2A fuse that blew (fuse 5 in Pete's photo, whose original value is 1.6A) and the same spark happened. Same burnt smell.

I checked out the 4 ohm/8ohm/16ohm taps from the power amp to the speaker and checked if my OT has an infinite resistance... nope, 0 resistance it says.

Now what did I hurt?