Hi folks,
I am struggling with an amplifier I have replace the output transistors in.
I states that it is critical to set the quiescent current when any components have been replaced.
Just incase I turn the unit on normally and they all blew again, I used the lightbulb trick and all was fine.
The light bulb lit and then dimmed immediately. I also put a known good unit onto the light bulb and it behaved the exact same way - so I deduced that all was well.
When checking the quiescent current I had an imbalance. One side read zero across the resistors (R's 4, 14, 44, 45)... the other read -76mV.
I could not set them and assumed it was because of the lightbulb.
So I removed the lightbulb - after all, it didn't "light" brightly and behaved in the same way as the known good unit...
I got sparks (from R42) and blew the output transistors again...!
My question is - should I be able to set the quiescent current whilst using the lightbulb trick...?
Appreciate any help,
Cheers,
Tom
I am struggling with an amplifier I have replace the output transistors in.
I states that it is critical to set the quiescent current when any components have been replaced.
Just incase I turn the unit on normally and they all blew again, I used the lightbulb trick and all was fine.
The light bulb lit and then dimmed immediately. I also put a known good unit onto the light bulb and it behaved the exact same way - so I deduced that all was well.
When checking the quiescent current I had an imbalance. One side read zero across the resistors (R's 4, 14, 44, 45)... the other read -76mV.
I could not set them and assumed it was because of the lightbulb.
So I removed the lightbulb - after all, it didn't "light" brightly and behaved in the same way as the known good unit...
I got sparks (from R42) and blew the output transistors again...!
My question is - should I be able to set the quiescent current whilst using the lightbulb trick...?
Appreciate any help,
Cheers,
Tom