Music - Recent Questions, Troubleshooting & Support

Failed output transitor

Marshall Music | Answered 9 hours ago

This amp has a design defect in the TDA7290 power circuit board. The heat sink is too close to main board when installed (at 90 degree angle) and can TOUCH the power signal on the board shorting out the fuse and/or transistor. I bent back the heat sink bracket slightly and it powered on fine. Also, the cooling fan must be 100% flowing or the transistor will cook in a short time, replace it also with new transistors (its a 5v computer chip fan). Good luck from Arlington guitar shop dot com.

Marshall MG 50 | Answered 9 hours ago

On main circuit board, remove the chassis

Marshall Music | Answered 10 hours ago

Does it ever turn off?
The PSRE313 uses a rubber on/off switch with a carbon dot on the underside that does wear out. If all is working well I would suggest replacing this rubber switch part number WD893400

Yamaha Music | Answered Yesterday

Request the schematic diagram directly from Phonic.

Phonic NEW... | Answered Yesterday

I moved you from computers to Piano , where you belong

we no 152 page so.. best fit.\\

why not go to the makers web site and RTM read the manual
google them.
1st hit lands me.

is my google better than yours, if yes why?

Kurzweil Music... | Answered 3 days ago

No idea how myself.
I tried a Google search and found several KB24 discussions, but you would need to communicate with people on those type of web sites to see if someone can assist you.

Bass Music | Answered on Apr 20, 2019

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