power supply transistor replacement help (please)

[spaceludwig]

Hello,

I would like to know if I can swap transistors TR28, TR30, TR32 & TR34 in the schematic below

which are rated at 80V 4.0A 30 Watts for transistors that are rated 80V 6.0A 65 Watts?

If no, what components would I have to change (other than the heat sink)?

Thank you in advance for your help/advice/suggestions, it is much appreciated.

 

[PRR]

You burned out all four transistors? Just the outputs or the drivers too?

 

[spaceludwig]

I am having problems with the present power supply in my console. It appears to have happened after i changed the ic opamps -  the new opamps are supposedly a little hungrier. The prevailing theory is that the extra juice the channels are pulling is causing the psu to go wonky. You can read the details around half way down page 2 of the "PM-700 mod/upgrade" thread.

My thinking - often faulty but willing to improve - is that by raising some of the specs of the power transistors (would those be the "drivers"?) they will be operating further away from their threshold and less likely to break down. Since the transistors there now have already been taxed by something i figure they've been damaged somewhat and might be close to permanent failure so replacement would not be pointless. Perhaps I could just change them for transistors rated at 80V 4.0A 40 Watts?

Anyhow, i appreciate any help or advice - particularly those that are backed by explanations.