Studio Caliber DC-2 - Lead Channel dropping out

Hello everyone!

I just bought a used DC-2. It's MINT. When I say mint, I don't think it's had 1 hour of play on it. BUT - I think that it has THE ORIGINAL TUBES in it. Again, someone owned it and just never used it.

Everything is great for about 10 minutes, then the LEAD channel go from great, to almost dropping out completely and sounding like a small transistor radio. Volume drops to 10% of what it was and sound has gone. Rhythm channel remains perfect.

I assume it's the pre-amp tubes, and I have gone ahead and ordered a full compliment of tubes for the amp, power as well.

Does that sound normal? Where a pre-amp tube would work up until it perhaps reached temperature and then go whacky?

Also, does anyone know what the 6 pre-amp tubes service...meaning...is the first 3 for Lead and next for Rhythm? Any help is appreciated.

Thank you all so much!

I have an update.

The LEAD channel seems to drop out when you switch BETWEEN Rhythm and LEAD. So, once it's been playing a few minutes, if you stay on LEAD you're OK. As soon as you go to Rhythm and back, it's gone.

Happens with or without the footswitch.

Hope this helps!