So I finally got the cajones up to try to fix this smoked mtx 1501d I got scammed on.
Replaced all the 75339 fets (all shorted out) and a couple melted poly caps right near them.
There's also a cracked (looks like physical damage) diode I replaced that leads to the fet in the center of the board.
I think the previous abuser of this amp "modded" it, since Q240 is missing.
So on first power up (no speakers, no inputs) I get the power led and about 3 seconds later LED238 near the input section lights up.
LED399 in the center of the large caps never lights.
Trying my test again with a speaker connected and an audio source. Soon as LED238 lights I get a very faint buzzing on the speaker. (About .1 volts on the dmm).
No idea where to go now.
Replaced all the 75339 fets (all shorted out) and a couple melted poly caps right near them.
There's also a cracked (looks like physical damage) diode I replaced that leads to the fet in the center of the board.
I think the previous abuser of this amp "modded" it, since Q240 is missing.
So on first power up (no speakers, no inputs) I get the power led and about 3 seconds later LED238 near the input section lights up.
LED399 in the center of the large caps never lights.
Trying my test again with a speaker connected and an audio source. Soon as LED238 lights I get a very faint buzzing on the speaker. (About .1 volts on the dmm).
No idea where to go now.
Have you check the gate resistors ? I noticed most of the time when the mosfets transistors blown the gate resistors go to. Take your DMM and check all the resistors that are in front of the mosfets.
http://www.samengstrom.com/nxl/10116/5_band_resistor_color_code_page.en.html
http://www.samengstrom.com/nxl/10116/5_band_resistor_color_code_page.en.html
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