Hot Rod Deluxe HELP!

[soberskipper]

Hey y'all,

I've been trying to bug people at AX84 for some help on this and I'm running out of time... and HAIR!

Hot Rod Deluxe
symptoms: sounds like "ring modulator" all the time no matter what. Buzzy, harsh, and awful. Yet you can hear the regular signal underneath the noise.
Will not bias past 3.3ma but Va is fine.

I have tried all non invasive measures including tube changes, speaker, etc. Makes the same sound when I plug directly into the "power amp in" of the loop, thus convincing me that the problem lie either in the bias supply or the output section.

All components in bias supply measure normal, all components in output section measure normal. I have desoldered the OT and checked it for continuity.... everything checks out fine. I even replaced a filter cap because there was some yellowbrown goop coming out of the + side...

Except no matter what I do, check, or replace... I can't get the bias pot to give me more than 3ma of current to the tubes.

V3

pin 1 - 208 V
pin 2 - 17.3 V
pin 3 - 26.3 V
pin 6 - 205 V
pin 7 - 18.1 V
pin 8 - 26.5 V

V5

pin 3 - 342 V
pin 4 - 341 V
pin 5 - (-44V)
pin 8 - 9 mV


Any thoughts?
Let me know if I should post a schem, gotta run right now though..
thanks
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Mexican recipes

[Structo]

I'm not sure what the problem is but here is a site devoted to the Hot Rod Deluxe, maybe it will give you an idea.

http://studentweb.eku.edu/justin_holton/

[Structo]

Look under Repair Help- Miscellaneous Problems Solved.

There is a guy there that has oscillations like you are having.

[soberskipper]

thanks, I have explored that site extensively!

still at a loss.

thank you
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SUZUKI BOULEVARD S83 HISTORY

[drz400]

One thing which doesn't sound like your problem but on the Blues Deville and Hotrod they took the power supply for the switching from the B+ and dropped it with a resistor soldered to the board. It go so hot it would unsolder itself. This cause the amp to switch by itself

[Andy Le Blanc]

examine R66....... its bypassed with diode and is what you measure the bias
ma./mv. across......... if its no good youll get all kinds of nonlinear distortion as the
diode conducts.......