Hi dear friends. I seek your advice. I have a nad 3100 integrated amplifier A few days ago I turned it on but no light bulb came on I opened the lid and found two fuses 0.5amp burned. I put in new fuses and the amplifier turned on for a second and again the fuses burned. I checked the circuit and everything looked fine Does anyone have any idea what is causing the malfunction? Thanks.
Obviously something is not fine,it could be anything from a failed bridge rectifier to blown output devices … which may well have been caused by problems further up stream. ( ie don’t just replace op devices if they’re blown, find the root cause)
As MikePP said, it could be anything.
A blown fuse should not be replaced before diagnosing and finding the problem(s).
Because installing a new fuse forces power into an already defective unit, and liable to destroy more parts in the process, making troubleshooting and parts replacement even more difficult and costly.
Just because looking around inside and stating "everything looks fine" is not a reason to power up something, because faulty components are usually not visible, asides from a blown fuse.
A blown fuse should not be replaced before diagnosing and finding the problem(s).
Because installing a new fuse forces power into an already defective unit, and liable to destroy more parts in the process, making troubleshooting and parts replacement even more difficult and costly.
Just because looking around inside and stating "everything looks fine" is not a reason to power up something, because faulty components are usually not visible, asides from a blown fuse.
Unless you are an experienced technician with suitable equipment, take it to a local tech
for evaluation and repair. An older unit like this (30 years) is likely to need substantial work.
for evaluation and repair. An older unit like this (30 years) is likely to need substantial work.
I tend to agree.
As an old service tech, I've had those amps on the bench.
The fuses in question are powering a complex bit of circuitry - not related directly to the power amp section, which has its own fuses, but just as important.