Jerry I am sorry you are having the same low power problem. It was making me and my test equipment look really bad.
There are three things I did to make it work. #1 Set the bias with no audio to 100mA then adjust R136 to get 1A long aahhh. You should see your watt meter go up at this point. #2 Replace the IRF510. #3 swap out the D20 dual diode for two 1N4148 through hole diodes. I am still waiting for the proper SMD replacements to be put in the mail. Finally, Farhan said this--- "i am not certain the bat54s are the culprit. in two low output cases that i came across on the bench, the 10 ohms in the emitter lead of the 2N2219 had cooked up.
it was a mistake in hind sight. that resistor dissipates 200 mw. it is rated for 125 mw. try measuring it once with power down. it should report 100 ohms or thereabouts. more would mean that it is bereft of life, it has expired, it has gone to meet its maker, it is no more! this is an exparrot, er i mean an ex resistor. sorry, i got a cold...
- f?
- f"
Aside from some others trying mic input amplification, this is the complete accumulation on the subject. Just start checking things off your list.
