transformer and transistor question

[rtill]

If a transistor is wired in wrong, can it hurt the transformer?
I suspect I have a transistor wired in wrong in my power amp I have built... the 300 watt mosfet http://www.circuits-lab.com/?p=81
My transformer gets extremely hot and starts to make a fizzle sound and there is no audio. I have my transformer and power supply setup as a test unit for all power amps I build, so I know that the power supply is correctly wired.

[Nico Ras]

Make sure that you have the mosfets placed correctly. Can you give your layout and I will browse through it to see if I can spot any mistakes.

Regards

Nico

[Nico Ras]

HERE IS THE FULL PROJECT PACKAGE including gerber plots and PDF files.

http://digisec.co.za/ras/music/RAS%2...mosamp%20Rev02

The PCB has been revised and made smaller. Remember that the power devices ar under the PCB facing up. In other words, the PCB clamps the power devices to the heat sink.

Kind regards

Nico

[Nico Ras]

Sorry, forgot the file extension

http://digisec.co.za/ras/music/RAS%2...mp%20Rev02.zip

[nigelwright7557]

Originally posted by rtill
If a transistor is wired in wrong, can it hurt the transformer?

If it becomes short it could overheat the transformer in a short period.

This is why I put fuses in the cct before the rectifier to catch any problems. 2 fuseholders is cheaper than a new transformer !

[AndrewT]

that's why I have to keep repeating that one should use a bulb tester for the start up of EVERY project and for the modification of EVERY project.

[Nico Ras]

Originally posted by AndrewT
that's why I have to keep repeating that one should use a bulb tester for the start up of EVERY project and for the modification of EVERY project.

I AGREE WITH YOU.

I HAVE OFTEN LOST OUTPUT DEVICES THIS WAY.

AFTER I BUILD IT I AM ALWAYS SURE THAT IT IS CORRECT.

I AM PROVEN WRONG MORE OFTEN THAN I WOULD LIKE TO ADMIT.

[rtill]

Originally posted by Nico Ras
Make sure that you have the mosfets placed correctly. Can you give your layout and I will browse through it to see if I can spot any mistakes.

Regards

Nico

Hi Nico...well, my layouts tend to follow the schematic exactly. ....part placement is exactly the same as the schematic. It just makes it easier for me to troubleshoot I guess. I did find my 2sj162 was wired wrong...I mistook the drain for the source and vice versa, I must not have looked at the schematic close enough. However, after correcting that, I plug in my amp and my transformer fizzles. I am assuming I probably ruined it from wiring the mosfet incorrectly. Am I correct in assuming that? Thanks for everyones help!

[Nico Ras]

Originally posted by rtill



Hi Nico...well, my layouts tend to follow the schematic exactly. ....part placement is exactly the same as the schematic. It just makes it easier for me to troubleshoot I guess. I did find my 2sj162 was wired wrong...I mistook the drain for the source and vice versa, I must not have looked at the schematic close enough. However, after correcting that, I plug in my amp and my transformer fizzles. I am assuming I probably ruined it from wiring the mosfet incorrectly. Am I correct in assuming that? Thanks for everyones help!

I guess you have fried them.

[nigelwright7557]

Originally posted by rtill



Hi Nico...well, my layouts tend to follow the schematic exactly. ....part placement is exactly the same as the schematic. It just makes it easier for me to troubleshoot I guess. I did find my 2sj162 was wired wrong...I mistook the drain for the source and vice versa, I must not have looked at the schematic close enough. However, after correcting that, I plug in my amp and my transformer fizzles. I am assuming I probably ruined it from wiring the mosfet incorrectly. Am I correct in assuming that? Thanks for everyones help!

Have you put fuses after the transformer ?
If not it could be a transistor(s) is shorted and putting a huge load on the transformer and making it buzz.