Altec 3 Speaker System Amp Repair

[derek92994]

Having a look at this one for a friend. Would power up but no sound. I'm suspecting these resistors are at fault as where the glue was on the circuit board had turned dark brown near these components. I removed them but can't remember what order they go back in. There is two different types and wondering if they run in pairs or alternate. For example one type is 1 & 2 the other 3 & 4, so like together (1,2,3,4) or (1,3,2,4) alternating. I know the short lead on the resistor goes into the circle printed on the circuit board so polarity is not an issue. Unfortunately I lifted a track while desoldering, hoping I can get some advice to get out of this mess.

 

[laatsch55]

No "before" pics??

 

[Gepetto]

And with the resistors out, did they ohm out as bad? They frankly do not look that bad. Looks like a switching power supply.

 

[orange]

oh, THREE-SPEAKER...

I was hoping to see an Altec Model Three.

So you lifted a TRACE, eh?

 

[derek92994]

I should have taken before pics. The resistors were covered completely with that black material you see on there, but what I should have done was taken note of what order they were in. That glue that had gone brown from heat could have fooled me into thinking these resistors are bad. I'll take more pics of the unit. Couldn't find any swollen caps.

Gepetto: I don't know anything about resistors or ohms etc

I do have a before pic taken by the owner, just found it:

Here are some other pics of the boards:

 

[Gepetto]

That was just black heat shrink tubing Derek. Likely used to insulate them since they are tall and standing up to prevent them from vibrating off the board in high shock environments, or they carry high voltage. This looks like the innards of a switching power supply.

 

[derek92994]

Thanks for the info. Makes sense as this board is inside the box of a sub woofer.

I gotta get ready for work.