Denon PMA 900V Fuse 6

[jtexfisher]

My Denon blew fuse 6 this evening. Quite the light show then a squealing sound like a kid letting air out of a balloon.

I suspect a speaker wire short. Don’t ask if I had exposed banana plugs crammed in sideways. I won’t tell.

I’m thinking to replace the fuse and power up with the volume all the way down, no speakers connected and see if the fuse survives.

Then power down, hook up speakers and test.

Good idea ? Dumb as rocks?

 

[mbz]

Quite the light show then a squealing sound like a kid letting air out of a balloon.

I’m thinking to replace the fuse and power up with the volume all the way down, no speakers connected and see if the fuse survives.

With that sort of damage it's kind of a pointless exercise but then again what does a fuse cost.
I'd say flip the power on then immediately (2-3seconds?) power off.

Better approach would be to build a Dim Bulb Tester, plenty of plans on AK, it's just an old school incandescent lamp in series with the AC active wire.

Second would be to diode test the driver and output transistors (with unit powered off), looking for a short, try in-circuit test first, may need to remove later for out of circuit test. Nice graphic from markthefixer on diode testing

 

[jtexfisher]

It’s alive!!!!!!!!!

And no more attempts to use banana plugs sideways in the binding posts.

 

[audiotemp]

You're lucky. You may have further developments, so pay attention (and do basic checks if you can).

Better approach would be to build a Dim Bulb Tester

IIRC, these particular amps do not work on a dim bulb tester.