Alpine 3545 blows all fuses after 5 seconds of power

[bmore5077]

I'm assuming you mean where the rca board meets the main. I don't think I can get to them but i'll try. Wish there was somewhere.more accessible. Thanks again.

 

[Perry Babin]

Pick a component on either side of the header to probe.

 

[bmore5077]

Ok so what happens is both sides play same level for about 3 min then the repaired side mutes when it warms up. Stays muted until it's turned off for awhile and cooled. Not sure what the deal is but this thing keeps throwing curve balls.

 

[Perry Babin]

How warm does it have to be to shut down?

When it's muted, does moving any of the switches/gain pots/RCAs make a difference?

The muting circuits are directly connected. The driver IC may have the ability to mute. Look up the datasheet for it and see if that's a feature of the driver IC.

 

[bmore5077]

It doesn't get really hot and both sides seem similarly warm at the driver ic heatsink. Movement of rca or switches gains don't change it once it mutes it stays muted until I turn it off awhile. thanks

 

[bmore5077]

Ok I had to remove the complete board to get the cover off from behind the rca pc board. I noticed where the board pins are soldered on the back side of the board some are soldered together. Is that normal...heres a pic

 

[bmore5077]

Picture

Picture from back of board

 

[bmore5077]

These are the header pins from the rca board to main. Thanks

 

[Perry Babin]

The bridging is OK. Look at the copper, it bridges the solder pads. If you were unsure, you could completely desolder, clean and examine the point where the pad meets the copper plane.

 

[bmore5077]

So odd enough if I read the voltage for the speaker outputs from the board and at the speaker terminals the side that was damaged and now sounding low reads a higher reading of .48mv and the other side that plays louder reads lower at .28mv. I would think it would be reversed. I'm really at a loss here

 

[Perry Babin]

That's likely DC offset. When measuring audio with a meter, you use AC volts.

 

[bmore5077]

Thanks. I still can't figure out why the one side plays lower. I resoldered the rca jack and it doesnt cut in and out now but the repaired side is still playing half volume.

 

[bmore5077]

Ok so finally I found the problem . It's a connector from main board to in between the driver chips. I bewildered and both sides are playing great. Question is when I set the idle current bias to 4mv +-.5 do I do that when it's warmed up or cold. Also same question for main voltage. Thanks alot

 

[bmore5077]

Ok so finally I found the problem . It's a connector from main board to in between the driver chips. I resoldered and both sides are playing great. Question is when I set the idle current bias to 4mv +-.5 each side from the test points as stated in the service manual .....do I adjus that when it's warmed up or cold. Also same question for main voltage. Thanks alot