Hi im busy with a 2.8kz targa but its staying in protection ive checked outputs and drivers amp builds rail voltage then trips in protection any ideas what it could be thanks in advance. Pics will be taken tomorrow if need be
I also found burnt resistors but the power supply drive circuit by the buffer transistors i think it could be those that is causing the protection to kick in and i dont know the value it should be
Is it ok if Q7 and Q8 is replaced with bd139 and bd 140
And the power supply mosfets are replaced with irf3205
And the power supply mosfets are replaced with irf3205
You can/should use the BD transistors. Mount them well off the board and solder top and bottom. Replace all 4 PS drivers. If the remaining good drivers that you remove are still good, save them if they're hard to get from your suppliers.
As soon as the rail voltage builds the amp shows the power on light for less than a second and then hits straight into protection with no output mosfets in
There are no mosfets in the output section as i checked them out of circuit just in case and used the lcr tester to make sure
Reinstall the output FETs and check the drive signals while the rectifiers are out of the circuit. With NO rectifiers and therefore no rail voltage, you can check the drive with the scope ground connected to the source leg of the FETs.