can anyone help me find schematics or boardview for MM1500KFD (down4sound amp)

[225xtrap]

i have searched nearly everywhere, and asked the company directly and they refused. i have negative 14.5 volts coming out the speaker out. they refused to RMA cause i am out of warranty. which is of course their right to do so, but unfortunately due to family circumstances i was unable to use it until now and it was DOA straight out of the box. i was hoping they would take pity on me but they don't care. you can't even download the user manual from them its crazy. i intend to fix this myself but i think it might be helpful if i had a schematic. as always any help is greatly appreciated.

[CapLeaker]

For starters… take it apart and make some nice straight shot high resolution pictures from top and bottom of the boards so we can see something.

[225xtrap]

here is what i have so far. i just watched a few videos to take off those clips and i will have more soon.

[225xtrap]

here are some more pics. i hope they are good.

[stj]

designer needs his ass kicked!
first thing to check is the soldering on that small vertical pcb,
you should NEVER have things like that on anything that could be exposed to vibration!

[225xtrap]

ill check if i can pull that out and take some pics. what is it? a discrete op amp? .. yah i am not too happy with the company. like i said it is my fault for not testing it before the warranty expired but they out right refused to even make a suggestion as to what to check in the circumstances i described and it coming DOA.. i.e. what is statistically most likely to be the problem.

*edit*
man is that vertical thing stuck in there, had a glob of hot glue on one side i cut away with a knife but still it is stuck. its pushed into those black jumper things (not sure what they are called right now) which means i should just be able to pull it out. i think.

another note, i have this thing mounted separate from the sub-woofer, so it will be isolated as much as possible. also since it never worked in theory it hasn't ever been vibrated.. unless they broke it with a test or something.

[stj]

it's hard to say what that does without a picture of it,
probably related to the power though.

[225xtrap]

this is the best i could do without taking it out. its very stuck, i am worried about causing more harm than good. i don't see anything on it that looks bad. if you think i should continue to try to take it out i will. or maybe desolder the 'single row female pin header' (i figured out what it is called)

[m1ch43lzm]

Not a car audio expert, but I see a TL494 in that daughterboard, it's for the power supply of the amp, the circuit there boosts the 12v from the input to whatever positive/negative voltage is needed for the audio amp section
That pinheader is soldered to the board
Post a picture of the bottom side of the board

Flip the board, connect the 12V supply, and wire in a switch from the middle terminal marked REM to +12v, carefully measure tbe voltage on the 2 big caps with the amp turned on, warning: high voltage there ,don't touch the caps or the MOSFETs on the PSU section, the caps are rated 100V, expect something close to that, the voltages on both caps should be similar to each other
After removing power, to discharge the caps use a 1K 5W wirewound resistor across the caps for around 10 seconds, check voltages with multimeter, repeat until you get less than 1v on each big cap


The + output looks like it goes from that thick wire
The section marked in yellow looks like the power supply, the orange section looks like audio related, except the big cap circled in yellow

[225xtrap]

that is some excellent info thanks. i haven't done it yet. here is what i have done. i checked as best as i can the mosfets and it looks like all the IRF 3205 on the audio side as you have laid it out are bad(or seem to be)and the far left RF B4227 is bad. i am going to try to source some of these parts to see if it is worth fixing.

[CapLeaker]

If the gate pin (1) is shorted to source or drain pin, you have to inspect the whole gate drive circuit and the driver IC too. It’s a class D amp. You also may need an oscilloscope.