audiobahn a18001dt

DREW028 · 2012-04-26 4:41 am

Does anyone have the repair schematics?

R323 r158? r101 c101 are burnt.

Amp draws current without remote wire. Positive wires of fan ready 3.25v and lights are dim.

timwebb · 2012-04-26 5:00 am

u check for any solder bridges?

Perry Babin · 2012-04-26 5:12 am

Are you sure that the burning of R101 (220 ohms) didn't blacken the others? The capacitor rarely fails. I don't know what the other two resistors are for.

Do you read any DC voltage on the negative speaker terminal?

DREW028 · 2012-04-26 1:54 pm

the amp still works. R101 is completly gone, r323 and c101 are ok. Do you know the value of r158?

Perry Babin · 2012-04-26 11:15 pm

I had this hiding in a different folder.

DREW028 · 2012-04-27 12:29 am

Q420 is fried. But the amp still had output?? Is that normal???

Edit: To me it looks like 2 power supplies to run the outputs. Am I correct?

DREW028 · 2012-04-27 1:15 am

One of the power supply banks shorted between the gate and drain. The gate resistors are ok, the drivers were ok but I broke the legs while testing and removing. Good new is I'm getting a pulse signal.

What is r101 for?

Perry Babin · 2012-04-27 2:06 am

R101 connects the RCA shield to the secondary ground. It generally burns when the positive speaker wire shorts to ground or when you have a transformer shorted from primary to secondary.

DREW028 · 2012-04-27 4:22 am

Transformers seem ok. No dead shorts .989 mohm. One set of output center legs are 70v and the other sets outer legs read -69.8.

Even though the gate resistors read ok ( lowest reading 99.0 ohms) they are a little discoloured. Will this be a problem down the road?

Perry Babin · 2012-04-27 4:41 am

The transformers sometimes have intermittent shorts.

The resistors shouldn't cause any problems if they're within tolerance.

DREW028 · 2012-04-27 3:04 pm

Will the way the power supply transistors failed somewhat help determine what went wrong? Only 1 blew up, the rest shorted between the gate and drain (in the first bank of transistors)

Perry Babin · 2012-04-27 3:37 pm

This is likely how all power supplies fail but the fuse doesn't open quickly enough and the damage becomes more significant.

DREW028 · 2012-05-07 11:49 pm

I need some help finding a replacement for ktc1027.

KTC1027 datasheet pdf datenblatt - KEC(Korea Electronics) - EPITAXIAL PLANAR NPN TRANSISTOR (HIGH VOLTAGE) ::: ALLDATASHEET :::

And kta1023

KTA1023 datasheet pdf datenblatt - KEC(Korea Electronics) - EPITAXIAL PLANAR PNP TRANSISTOR (HIGH VOLTAGE) ::: ALLDATASHEET :::

These are used to drive the P.S gates

Perry Babin · 2012-05-08 12:51 am

I've been using the BD139 and BD140. I think that most people ordering the originals have been buying them from China.

DREW028 · 2012-05-08 12:55 am

Nice, I wasn't sure if I could use them. Thank you.

DREW028 · 2012-06-02 2:21 am

Well I've had this one put to the side waiting for the owner to pick up. I was testing it periodically and everything was fine. Today while hooking it up in the guys car it was on for a few seconds then smoke. I was embarrassed and almost blew my top.

One of the transformers has a short at the very last winding. I can see it spark. I guess I got lucky since is a easy fix. It did take out the transistors again though.

What should I use to coat this with?

Perry Babin · 2012-06-02 2:29 am

Post #8.

audiobahn a18001dt

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