Fender Champion 20 Solid State Amp - lights up. no sound

[earache]

...so with that, I've decided to order the TDA2050 from the EBay source given, as well as some TL1.6A fuses, I will replace the bad components when the new ones arrive.
With the fuse blown I can't do much more than that now anyway.

[earache]

While waiting for the TDA 2050 to arrive from Ebay, I tested the fuse and it's actually OK. I must have completely killed the existing TDA20-50 with my testing mishap. I found a used one on my scrap pile in a Fender Frontman amp. I put it into the Champion 20 and I'm back to where I was, with lights on everywhere, sound thru the headphone jack, and no sound at the speaker. Speaker works and the speaker leads are OK as well. There's a "pop" thru the speaker when I turn it on or off.

[g1]

There is a mute circuit that is triggered by the headphone jack.
Look at the lower right area of pg.2 of schematic. Check the DC at D1 cathode with headphones connected and again with headphones removed.

[earache]

Hey g1 - the measurement at the cathode of D1 doesn't change when the headphone jack is inserted.

I tested the diode in circuit with my meter on diode setting - meter reads .58 with common lead at cathode, and 1.9 with leads reversed.

So it seems the diode is bad, unless there is some other component on the board that is influencing the reading.

[g1]

That sounds like a fairly normal reading for the diode. Probably if you lift one end you will find the reverse biased reading goes from 1.9 to 'OL' or however your meter displays 'open' in diode range. Usually a diode range calls 2 or over 'OL' so the 1.9 isn't far off and may be due to parallel circuits. A reading of .58 seems in the ballpark for a forward biased diode.

More likely the problem is with the headphone jack switch. With no headphones plugged in, the 'R' should read 0 ohms to the 'RS' pins of the jack. Upper right area of pg.1 of schematic. If it does not read 0 ohms, it could be a dirty/oxidized or defective headphone jack.

[earache]

I tried shooting that headphone jack full of DeOxit with no change. I suppose that if I don't use the headphone jack that I could permanently jumper the switch to always be choosing the speaker instead of the headphones, correct?

[g1]

You could, but first you must determine if it is the jack itself, or some other fault in the rest of the 'headphone detect' circuit. That's why I asked you to check resistance at the jack switch contacts in post #20.

[Eman2206]

I have the same problem how did you fix it?