Directed d2400 interesting problem

[rapcrash]

Hi,
First sorry for my English...

I got some problem with my Directed D2400 amp and I can't find a way to fix it. When power's up, green led stays on, not going into protection mode, but no output. I have checked the power supply, it's OK, at the middle pin of the rectifiers I got +-60 V, at the 640 and the 9640 output banks i got leg 1 - 59.9V , leg 2 -0 V, leg 3 - 59.9, on both sides of the amp, they seems to be OK. Any other idea?

[nigelwright7557]

I would check the mosfets for a short D-S.
Other than that could be the class d chip has gone.

Alos check G-S for shorts, I have found that fault a couple of times.

[rapcrash]

I don't have found any short's but, i have taked out all of them and checked piece by piece, by charging them with a multimeter and discharging with my finger, and a irf640 and a irf9640 doesn't hold the charge (or they doesn't charge up). I think this is the problem. What do U think about?

[nigelwright7557]

When mosfets blow they usually go short S-D.
I have seen short G-S a couple of times.
I have never tried to charge one up.

Apply a sine wave to the amp and see where the signal stops.

[rapcrash]

I have replaced them, but still nothing. No output. I got 2x TIP41C and 2xTIP42C transistors, what are getting hot in very short time, but I have taked out, and they are ok. There is also 2x 2,2Kohm 3W resistor what also gettin hot very quickly. They are marked with red. On the pictures is missing a capacitator (I put it back, it's OK), and the 2x TIP41C transistors. Any suggestions where I can continue my project?

[rapcrash]

Somebody got a schematic for this kind of amp? I think it's the same board what the Brutus 1200 amplifier uses. Thank you in advice

[rapcrash]

I have found 2 pairs of faulty transistors on the driver board. Somebody can help me to identify them? One of them is DK QQ - I got 2SC4672 for them but I can't find anything for AG QN. Any idea?