Onkyo Sub will not power up (fuses blow)

[zsmith28]

Hey all. I have an Onkyo SKW-540 Sub that will not power up. The LED is no longer illuminated. I took of the back panel and found the 5w/125v fuse has blown. I replaced the fuse with a 5w/125v fuse, but it blew when I plugged the sub back in. Any ideas to what could be happening or how I can fix this?

Thank You.

Zach

 

[bob91343]

You need a service manual. Apparently the amplifier has failed.

 

[zsmith28]

Where can obtain one of those? Any idea if this would be a costly repair?

Thanks

 

[oodqui_ric]

one of your power amp output might be shorted. i suggest to see the parts of the unusual appearance like burned or cracked parts, they should be replaced to avoid future problems. Also, try to test the parts of the out-circuit. (never try to power-up the circuit with unpaired output)

 

[davygrvy]

Where can obtain one of those? Any idea if this would be a costly repair?

Thanks

1) from the company that made it.
2) probably just the freight cost if under warrantee

But you have to ask yourself, do want to fix it or have someone else. Start by finding your nearest local Onkyo authorized service center.

 

[bob91343]

It's probably a major repair job. Not too expensive if you can do it yourself but consider replacing the unit if you have to pay for a repair.

 

[davygrvy]

If the sub is sent in for repair, that's exactly what they'll do. The tech will grab a new power amp module from the shelf, replace the bad one, test it, mail it back, done. Whether it cost you much is determined by the warranty status.

Blowing fuses is the symptom of shorted output devices. Probably 2SA1943 and 2SC5200 transistors, but that's just my guess from usual asian gear. Test center pin to the side with the ~0.22 ohm emitter resistor with your meter on diode test. If you get zero, you have at least a pair of bad apples. And they always go in pairs 🙂

Well, once I saw one NPN and two PNPs, but that was a rare occurrence.