SX780 no fuse board on Bottom

[faccan]

HI, this is my first post.
I'm very thankfull to every person that help other to solve problems. You must to know that with every post you are helping hundred of people.
I bought for almost nothing a SX780.
It turns the lights but never click.
When I opened i didn't find the fuse board at all.
Is it possible that Pioneer not include this board in some units? I swear that the unit wasn't open before as it has about 1kilogram of dirty inside.
Thank you very much in advance!

 

[glen65]

The fuse board is on the bottom in close proximity to the power transformer. You need to remove the bottom to access it.

 

[faccan]

The fuse board is on the bottom in close proximity to the power transformer. You need to remove the bottom to access it.

Thanks for your answer, but here is why I asking... There is no board!!!

15196956735581880637865

• faccan
• Feb 26, 2018
• 1

Sx780 no fuse board

 

[faccan]

 

[glen65]

Thanks for your answer, but here is why I asking... There is no board!!!

15196956735581880637865

• faccan
• Feb 26, 2018
• 1

Sx780 no fuse board

Thanks for the pics.
Looks like that one has the rotary selector switch on the back. So you have what's called a 780 "s" model, which is an export model and doesn't use the fuse board.

 

[faccan]

Thanks a lot. So now I have to find why is no clicking...
Thanks again

 

[glen65]

Thanks a lot. So now I have to find why is no clicking...
Thanks again

Here are some possibilities...
1 a missing supply voltage.
2 Protection circuit is sensing dc voltage at the output stage. No dc is supposed to be present. A common amplifier fault is one or both STK0050 ICs.
3 Fault in protection circuit itself that drives the relay. That could be anything from a bad solder joint on the board, to the PA3004 protection IC itself. Or it could simply be a bad relay.

 

[faccan]

And the winner is...... BAD SOLDER JOIN under colector of Q25!!!!

THANKS GLEN.. Thanks to audiokarma.

 

[glen65]

And the winner is...... BAD SOLDER JOIN under colector of Q25!!!!

THANKS GLEN.. Thanks to audiokarma.

Good deal
That would keep the supply voltage from reaching the 3004 protection IC. Good to see it wasn't something serious.

 

[merlynski]

I would also suggest putting bigger, better heatsinks on Q25, Q19 and Q20, as they have a long reputation for bad solder connections developing because of their excessive high temp operation.

 

[faccan]

Yes, the problem now is find a better heatsink that is small enoughs to be replaced without touching anything

 

[jerrycpor]

Mouser 532-530613B00 Heat Sinks with 532-4880SG Mounting kits work perfectly.

 

[faccan]

Mouser 532-530613B00 Heat Sinks with 532-4880SG Mounting kits work perfectly.

Thanks you very much!!!!