Rare beast NRG Control A401M class A monoblock

J!m

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#4
Is it in that thread? I read about seven pages and then jumped to the end... or if it’s elsewhere, that’s cool.

I’d like to have a friend (he’s an EE) look it over.
 

J!m

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#8
Great movie.

I’ve been a Python fan for a long time and even met Michael Palin in Timbuktu.
 

simonsayz69

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#9
hey guys, greetings from India. I have recently acquired a NRG control 401S behemoth. I am encountering a problem in the right channel where by there is a distortion in the mids and the highs which fades away in the high volumes. I have cleaned the entire circuits and the relays and tightened all the connections and have also sprayed a contact cleaner on the all the contacts but the distortion remains. since there's little or no info avaialble on the net on the manual and the schematics I am skeptical to proceed further. Can any help me in procuring the same. i have also written am email to Mr. Denton Clarke who was associated with NRG back in the hey days but he hasnt responded so far. the giant transformer is also making a Hum but that I can live with, but the distortion is killing me. kindly help.
 

J!m

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#10
I'd say look to the referenced thread above and see if the stereo schematic is there, or maybe the mono one can be used for troubleshooting...

And welcome.
 

George S.

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#14
It probably needs new electrolytic capacitors. The humming transformer may perhaps be quieted by carefully tightening the mounting hardware.
 

George S.

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#15
Oh, and your in India! Before going any further make sure it's wired compatible with your electrical service. Looks like the company was based in Minnesota USA, so 120 VAC, and a 3 wire cord, line, neutral, ground. What you have for service there I don't know, but it must be wired compatible to be safe and work correctly. Close enough isn't good enough. Don't mix grounds and neutral, or heaven forbid line.
All the issues could be caused by improper power cord wiring or service voltage.
 
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laatsch55

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#17
attached here with this is all what i was able to dig from the other forums n this one n the net. the schematic on this one does not mention 401s in the list but mentions the A400m and A400S. any insights ?

High power, discreet FET's in the output stage?? I wonder if they are obsolete..
 
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