Carver M 1.0t Heating up

Hi Carverophiles! I have a strange problems with my nice M1.0t. Inputting a 1K waveform, the output starts very low, suddenly increases a lot then it goes back to being very low and so on. While this is going on, the transformer buzz and Q130 becomes Very hot! So far I replaced various transistors such as Q120, 110, 117,118 etc. with those suggested forthe MkII modification and all the small value electrolitic caps plus those for the +-30 branch of the power supply which still shows a little ripple.

Any advice for troubleshooting is appreciated!

Thanks!
Antonio

If your power supply is still showing ripple, I'm betting on a bridge rectifier somewhere. You might try some freeze-it and spray around some of the rectifiers and see what happens.

Do you mean those diodes on the daughterboard next to the transformer? But why is Q130 quickly becoming hot?

Thanks for the input!
Antonio

The ones I was thinking about were the packaged four prong bridge rectifiers.

Ok. Q 130 substituted with NTE equivalent. Now does not get heated quickly anymore. Also the 8 raised diodes have been substituted with NTE 576 equivalents. None of the old ones tested bad. Also all diodes in the power supply have been tested good.

Now the amp stays on for 1/2 second ( I can see a nice waveform at both outputs) with the meters increasing. Then it stops and there is no output for like 2-3 seconds; then does this again. When it goes on, 60 and 100 V rails drop slightly. 30V rail still shows some ripple on both the + and - site.

What would you suggest as next move, beside flattening the amp into a pancake?

Thanks

Antonio

PM sent.