Help a noob troubleshoot his 41hz Amp6

[migrane]

So I got the Amp6 built it and now I am getting no sound from it
Here is a bit of a background. I got a Radioshack transformer that puts out 13.x V, 3A. I tested the power part of the circuit while building and it was up to spec. I built the rest of it and what is happening now is I connect the power to the transformer and I get like 2-3 seconds of distorted music after which it turns into crackling and a hiss and that is about it. The red led comes on briefly and the green one now stays on and flickers from time to time. I have checked all the solder points for the rectifier, regulator, toroids, caps, tripath, diodes etc etc. I made sure that the diodes were soldered properly and they are ... so I dont know what else more to do about it ... the green led is hooked to the fault line on the tripath. Yet I dont know where to start looking for problems
Any help is welcome.

Migrane

PS: went on to the 41hz forum asking for questions but it doesnt seem to be that visited. Only one helpful person answered.

 

[migrane]

partial success curved by some autoprotection

Ok, So I got it to play for more than a minute now. I had resolder my input connections I was using a common ground for them and that seemed to have solded the issue of no sound. Once again I oversized the heatsinks for the rectifier and regulator as well as for the tripath. They are getting pretty hot. At C1819 I now get 14.1V which i suspect is normal. Once again the green LED is constantly lit and after a minute or so of playing the amp turns off. The rectifier and regulator dont generate heat anymore and that is it ... I leave it sitting for a while and then I can repeat and the same thing happens. I traced all the outputs to the tripath pins and something really wired is happening. I can touch on what looks like it is pin 26 and see continuity with an ohm meter to every output on the board. Now according to the schematics from the original tripath test board I shouldnt be able to do this. Wired !

I'll keep on looking ... any further suggestions are very welcome.

thanks,
Migrane

 

[Pano]

Sure sounds like you have a short somewhere in the output circuit. The amp must be going into over current protection. That could also be caused by a short at the inputs. Please check for DC at the outputs.

If the amp goes into thermal overload, it will shut down them come back on when cool. With over current shutdown, you must remove power to reset the amp. That will give you a clue as to what might be happening.

 

[migrane]

Thanks for the reply. I will try to check the inputs tonight going by the schmatics from the original test board of the Tripath chip. We'll see how it turns out.

Migrane

 

[mourip]

Just a thought.

Be sure that the two output channels do not have the grounds tied together and that neither ground is tied to the chassis. The outputs need to "float".

Good luck, your efforts will be worth it!

Paul