Overheating Class A

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I have a Musical Fidelity P270-2, It has been much modified over the years with Black Gates, schottky diodes, star earth etc. I have had no problems for a long time and was quite proud of it considering I am no electronics expert! the amp itself sounds superb! I used it with Musical Fidelity P173, kit valve and lightspeed pre-amps with no problem whatever, having had the amp returned from Portugal by freight recently, it now overheats on the right channel only, in fact the heatsink gets so hot it would cause a burn if touched.The amp is working but I use a gainclone kit instead but just not the same quality. Has anyone had similar problem with large Class A amp? I would be interested and any help would be appreciated.:(
 
Fault found

I now know that a resistor is burning out, I have marked this on the drg. I downloaded from this site which was kindly posted for another problem.
Does anybody have any idea why this resistor would keep blowing? The amp still works but I guess because the other two FETs are having to work harder the heatsink on this side gets so hot I feel it could cause further damage over a period of time!:eek:
 

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Hitachi J162 Mosfet

Hi, Have found that Aura Note Premier uses these devices. I cannot find any Hitachi devices on the www I can only find Renesas, would these be drop-in replacements for the faulty one or would I be better to replace all to keep everything ballanced? I am a bit wary of buying on the www from China source due to the stories of fake items being produced there.:(
 
I now have another problem with the same unit, I shorted the output on one channel and now have no output on that side. I noticed that one set of fet's were not heating up so I have changed these but still no output. There is no sign of any component failure etc. any suggestions please?
 
No output on one channel

I have shorted out the output of one channel and it is now dead! I noticed that a pair of the j162/k1058 were not heating up so I changed them but still have no sound. I can see no damage to any components so I am stuck, I will try and post a picture. Any suggestions please?
 
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