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JVC ja-s310 blowing a fuse

Treyson

Treyson

New Member
Hello AK!

I am stumped. I have a JVC ja-s310 that is blowing fuse #2. Initial thought was to recap the whole system so I did and if nothing else that was a great learning experience but after making sure everything was clear and correctly installed I tried to turn it on again and the fuse fired up on me immediately. Looking at the board (I think schematics confirm this but not entirely adept at reading that), the fuse is the first thing in line from the power supply.

So my questions are as follows.

1) it calls for 3.3a fuses but they are hard to find so I am using 3a fuses. Is this too much of a difference for the replacements to handle?
2) is the power supply putting out too much power? If so, how does one go about fixing that?
3) I have about $20 into this project, should I cut my losses and part it?
4) while writing this I found something interesting. There is a voltage... selector? In this guy that allows me to switch between 100 v and 250v. What is this thing and is it possible that that's not doing its job? On the 100V the fuse frys immediately and on 250v the fuse bends a bit and then eventually frys.

Thanks for taking the time to read this.
 

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Three words - Dim, Bulb, Tester.

Most likely something is overloading the power supply, and continuing to "test" fuses is not going to solve it. The 3A fuses should be just fine, although the 3.15A Littelfuse is pretty common and will be close enough once the problem is located and resolved.

I would suggest testing the power supply rectifiers (D801-D804) and main filter caps (C801/802), and then testing the power amp 2SB507s and 2SD313s for shorts. The MJE15032G/MJE15033Gs are suitable replacements, and are under $2 apiece. Of course, surrounding components should be tested for damage as well.
 
Treyson said:
4) while writing this I found something interesting. There is a voltage... selector? In this guy that allows me to switch between 100 v and 250v. What is this thing and is it possible that that's not doing its job? On the 100V the fuse frys immediately and on 250v the fuse bends a bit and then eventually frys.
Click to expand...
Leave the switch set to the closest position to the AC mains in your area (120v USA) etc..
 
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