Amp4 fried, need some tips
had this posted up the other day but it got mistakenly deleted for spam.
My amp4 had been working well. Then, while trying to hook up my mv02 to it's own power supply while the mv02 was in the front panel, I got a bad hum. I unhooked the AC wires to the little 14v psu, let them drop, and turned the main power back on. Like an idiot. So 15v ac got shorted to ground. Actually, to the bottom panel of the chassis as I have since realized that the bottom panel isnt in contact with the front and back panel.
The 2050 chip instantly started smoking and snapping. I have since replaced the 2050, which was the only visibly damaged component.
Then I (foolishly?) just powered the amp back on with J5 and J10 closed and nothing happened.
I opened J10 and J5, and measured:
A. 5v at J4 Pin 7 to J3 Pin 4
B. 9.7v at Q10 to gnd, and
C. 8.0v at Q10 to agnd.
With J10 open and J5 closed I measured:
A. 38mv at 4 Pin 7 to J3 Pin 4
B. 7.7v at Q10 to gnd, and
C. 1.8v at Q10 to agnd.
I am not sure if Q10 is supposed to be measured to gnd or agnd. The schematic makes it look to me like it should be agnd.
Anyone have any input on the above readings?
Thanks in advance, and I am going nuts with my stupidity.
By the way, that low temp solder is brilliant for removing components. It's so easy anyone can do it!
"One of the great things about books is sometimes there are some fantastic pictures."
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