I have a completed K8060 Amp. I have the Trim Pot turned all the way up and R19 has only 3 mV across it. I am not sure what the problem can be. I checked the transistors and they are in the right place. I checked the soldering and it looks okay. Please give me a list of what to check based on your experience.
Make sure heat sensing transistor is correct and correctly mounted.
I am assuming that the heat sensing transistor is T6. It looked alright to me - but I added more thermal paste and used a different transistor (same model). I still got a bias voltage of about 3 mV. Since I changed the transistor, I am assuming that there is something wrong with another part of the circuit. What else do you think could be wrong?
Difficult to tell without being able to investigate your circuit.
If you could post hi-res pics of both component and solderside (not on this forum, on a free picture base or similar), then we could take a peek at your assembly.
It has been a while! Here are the pics - don’t worry about Q6 - I don’t have it soldered on the whole time for these pics.
i34.photobucket.com/albums/d101/ … mp/063.jpg
i34.photobucket.com/albums/d101/ … mp/064.jpg
i34.photobucket.com/albums/d101/ … mp/065.jpg
i34.photobucket.com/albums/d101/ … mp/068.jpg
i34.photobucket.com/albums/d101/ … mp/074.jpg
Pictures are not very sharp.
Anyway, some solderjoints look poorly soldered.
Make sure to apply heat long enough to allow solder to flow.
Is there a way for me to ship the board to velleman and have it checked and repaired. If so, what is the cost and where is that info.
If there is such a service would you recommend it?
You can return the board to:
Velleman Projects Tech Dept.
Legen Heirweg 33
9890 Gavere
Belgium
Repair is less than price of a new kit. Shipping not incl.