PCB Soldering Help!

[audiogeek]

hey folks,

i just picked up an 80's pro/sumer caliber 2 track tape deck, and I'm having an issue... i'm trying to narrow down the problem area, and any help you can offer is appreciated!

I'm running out a Digidesign 192 (+4dB) into a -10dB inputs on the tape deck. Not sure about impedance matching between the two devices; I can't find any impedance specs for the 192 analog outs anywhere.

when I got the tape deck, the Channel 1 input PCB board was unseated from the motherboard, so no input getting to that channel. I seated the board, had input and output, everything is great, then short while later all of a sudden no output from either channel!

I popped off the back, and it looks like the solder points behind the multipin interface to which the input cards attach are burnt out, but this is where my inexperience is a problem. As best I can tell, nothing completely melted or blew up, but the solder points at the Channel 1 and Channel 2 interface to the motherboard do appear to be brownish, almost smokey. Definitely not as shiny as all of the other solder points on the whole machine...

... I've attached a photo for reference. It's pretty fuzzy, but you can get a sense of how un-shiny the solder points are, underneath the white clips. There's another much cleaner solder point off to the right, for comparison.

So, what do you think? Does this look like I fried my motherboard? Would connecting the tape deck in such a way even cause this kind of damage? Is this fixable? What is the meaning of life?

Really, I'm in the dark on this stuff, but trying to learn. If you have any thoughts please share them...

Thanks

[mexicola]

I've burned pcb's before from accidentally improperly hooking up voltage headers. You end up with a blackened pcb and charred traces...you haven't burned your pcb.
The pic is difficult to see, but it doesn't look like there's anything really wrong (although a high res pic would be nice). Just looks like aged rosin, or possibly oxidation. You could always re-solder them.

[audiogeek]

Originally Posted by mexicola

I've burned pcb's before from accidentally improperly hooking up voltage headers. You end up with a blackened pcb and charred traces...you haven't burned your pcb.
The pic is difficult to see, but it doesn't look like there's anything really wrong (although a high res pic would be nice). Just looks like aged rosin, or possibly oxidation. You could always re-solder them.

Awesome, thanks I guess that's good news. Definitely nothing blackened on the PCB, nothing charred... That just means I'm back to square one on figuring out what's up with this thing.

Sorry again for the blurry pic (iPhones cameras suck btw), and I hope you're right. I do see how this could just be aged rosin... None of the other solder points on the other pcb's look aged in this way. Time to dive back into the service manual...