Can anyone offer any advice with this one?
I recapped this NAD amp and upon power on two fuse blew on the power board. So after examining I found two embarrassing mistakes. I had shorted the voltage regulator trace and had installed C524 the wrong polarity. So after fixing these mistakes the fuses still blow. Not the first two, they're fine, but there's an electrical hum sound then the second two fuses blow. The rest of the amp has been examined.
It's a handy amp and I'm hoping to restore this power board.
I've attached pics with red markings to show the fuses that blow and the cap I reversed.
Thanks guys!
I recapped this NAD amp and upon power on two fuse blew on the power board. So after examining I found two embarrassing mistakes. I had shorted the voltage regulator trace and had installed C524 the wrong polarity. So after fixing these mistakes the fuses still blow. Not the first two, they're fine, but there's an electrical hum sound then the second two fuses blow. The rest of the amp has been examined.
It's a handy amp and I'm hoping to restore this power board.
I've attached pics with red markings to show the fuses that blow and the cap I reversed.
Thanks guys!
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Can anyone offer any advice with this one?
I recapped this NAD amp and upon power o two fuse blew on the power board. So after examining I found two embarrassing mistakes. I had shorted thr voltage regulator trace and had installed C524 thd wrong polarity. So after fixing these mistakes the fuses still blow. Not the first two, they're fine, but there's an electrical him sound then the second two fuses blow. The rest of the amp has been examined.
There are other threads in these forums about repair of old NAD amplifiers. You might find some useful ideas in these threads.
I repaired a 320BEE which had intermittent fluctuations of audio volume unless the cover was removed. The cause was thermal problems or hotspots in the chassis caused by inadequate ventilation and the use of vertical plates for transistor requlator circuits. I installed a small circulating fan which reduced the internal temperature by 10C degrees. Now it is good.
I recapped this NAD amp and upon power o two fuse blew on the power board. So after examining I found two embarrassing mistakes. I had shorted thr voltage regulator trace and had installed C524 thd wrong polarity. So after fixing these mistakes the fuses still blow. Not the first two, they're fine, but there's an electrical him sound then the second two fuses blow. The rest of the amp has been examined.
There are other threads in these forums about repair of old NAD amplifiers. You might find some useful ideas in these threads.
I repaired a 320BEE which had intermittent fluctuations of audio volume unless the cover was removed. The cause was thermal problems or hotspots in the chassis caused by inadequate ventilation and the use of vertical plates for transistor requlator circuits. I installed a small circulating fan which reduced the internal temperature by 10C degrees. Now it is good.
