To me, as far as today's offerings, that "high end" and "high priced" stuff is not worthy of the title they put on things.
High End is mostly a meaningless title to justify the higher price.
And anyone who wants to argue that point can do some digging to see the needed repairs and dissatisfaction ratings of these products - compaired to even "consumer grade" products made decades ago.
Why do you think that "vintage" equipment circa 1960's - 1980's has such a large following and in demand?
That stuff had style, and lasted for decades without troubles, even though today requires some age-related servicing.
It's about reputation, quality, longevity.
If Poundy happens to be still on here I was hoping to pick his brains. Dragged an olf friend of mine out the loft the other day (3130) sadly she died a while ago and has been gathering dust since. I think (oh the shame) I poss connected the poor old girl up wrongly round at a mates house to a mixer on dj setup (whilst P155ed up🙄) and blew the amp up😢.
Anyway im stuck at home I'll with something so thought I'd have a go at repairing it.
What im slightly Puzzled with is My service manual from nad doesnt seem to show any voltages?
Prob i have is very low distorted output from both channels.
Currently testing the 2n3055s and the mj2955s all seem ok so far as do the drivers b4 them.
I was thinking surely this must be something before this stage if distorted output is both channels, so is the op amp to blame? but if so wouldnt i surely hear nothing?
Any suggestions? 1c301 njm2043 seems to have very low voltage on it.
BTW do we think i can measure on the rest of the amp with the 2n3055s and mj2955s out completely?
PS i have no signal injector or scope so managing with just dmm
Thanks In advance for any help anyone can offer (and no i am not hrowing it in the bin😆)
Anyway im stuck at home I'll with something so thought I'd have a go at repairing it.
What im slightly Puzzled with is My service manual from nad doesnt seem to show any voltages?
Prob i have is very low distorted output from both channels.
Currently testing the 2n3055s and the mj2955s all seem ok so far as do the drivers b4 them.
I was thinking surely this must be something before this stage if distorted output is both channels, so is the op amp to blame? but if so wouldnt i surely hear nothing?
Any suggestions? 1c301 njm2043 seems to have very low voltage on it.
BTW do we think i can measure on the rest of the amp with the 2n3055s and mj2955s out completely?
PS i have no signal injector or scope so managing with just dmm
Thanks In advance for any help anyone can offer (and no i am not hrowing it in the bin😆)
just been sat watching telly with my meter, seems all output transistors are good🤔 Anyone know where you can get the insulators for these? both the thin T03 shaped ones but also the tubular ones for the bolts. what are they called if i search?
ta
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thankyou Mooly, quite handy as cpc is 10 mins from my house. shame the buggers close at weekends now tho
"TO3 thermal pads" and "top-hat washers" or "shoulder washers" are good search terms. Nylon is typically used, avoid polythene as it melts/distorts at too low a temperature - for harsh thermal conditions something like PPS or PTFE would be the best choices, but I suspect those would be hard to find.
sorry my PC blew up at the weekend so couldn't get on here 🙁 I do have quite a few originals if you want to PM me
A common fault with these units is the the 2 main transistors in the regulated supply. For some reason its an area that gets quite hot and the solder legs are always loose on the board.def check these out
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Thanks poundy, funnily enough I took one of these out yesterday as was getting hot, didnt meter it for some reason, prob coz i was fed up/sick of playing with it. will check with dmm 2day, im expecting short though due to how hot it was. will check the other one also.
with the solder shorts removed, what current are you getting, it should be around 26mv/ma across the 1 ohm