Join Date: Jul 2004
Location: Scottish Borders
Originally Posted by gianmarco
............... connected my light bulb, tester ready, and powered on the amp.
A bad hum came out from the driver, the bulb was glowing hard. I knew something was wrong. Turned off.
Re-checked all again, There was a transistor turned, so instead of CBE I was connecting as EBC. this is due to its strange positioning (is T6, the one IN the heatsink) upside down that send me in troubles.
I retry again to power up the amp. No changes, same hum from the driver.
Re-checking again I found a big mistake in the pcb, a track that should go to -40V was actually going to +40V. Fixed it the result is this:
a little flash of the light bulb
the bulb is not even glowing, completely cold.
the amp is working, voltages are fine (about 35V)
Use that bulb tester to start up EVERY time you change anything, no matter how minor you think that change is.
After the tester proves you have no mistake, then power up direct.
AFTER EVERY change !!!!!!!
regards Andrew T.