HR Deville with oscillation

[ahamay79]

Hi guys,

I'm getting a "motorboating" type of oscillation on a HR Deville with known good tubes. The problem doesn't really start untill the bass pot is turned up past 4-5. Then other knobs can change the frequency and rate of it. Also, I get a voltage drop at C35 when the oscillation starts.

Any ideas?

thanks,

D

[yankeerob]

Funny - I've had this way back when - the PI - in my experience - is one of the most vulnerable areas PCB-wise on the Dv - just out of interest is it a 212 or 410? Have a good look around the PI tube socket... this illustrates all the lifted tracks I had to hardwire when mine was still a Deville...



There's a lot of heat/vibration goes on here - well that's my theory anyway... someone's bound to come along and tell me I'm talking crap...

[ahamay79]

It's a 212. Let me also note that someone turned on the amp with both power tubes being broken in the sockets. I replaced the tubes and heard the motorboating. I'm about to quit working on these things.