Solid Audio 2500D - pls identify U2 & U3

[nonprof]

Hello!!! Good Day!

Could somebody help me to find the part number of U2 and U3(maybe identical?) for a driver board of a class D amplifier Solid Audio 2500D?. These drives output MOSFETs.

I'm thinking that this is the culprit of DC offset protect and heating of IRF9640s and IRF640s.

Thank you so much guys! help is very much appreciated...we dont have much resources here in our country. Sorry for my poor camera...

[timwebb]

got a picture?

[Perry Babin]

There were two versions of this driver board. Does pin 8 of one IC connect directly to pin 8 of the other IC?

[nonprof]

Hi Perry, pin 1 and 4 of U3 are connected to Pin 4 of U2. Yes, Pin8 of both ICs are connected. Can you please give the part number so I can order it today? Order parts willbe coming from U.S. it takes two weeks:-)

Thanks to your usual support...

[Perry Babin]

It's not likely that these parts are defective. The IC with pins 1 and 4 connected is an LM211. The other one is a TL072.

[nonprof]

Originally Posted by Perry Babin

It's not likely that these parts are defective. The IC with pins 1 and 4 connected is an LM211. The other one is a TL072.

thanks! for having these numbers.
.
do you have an idea what is the problem? the first problem of this amp is when the relay turns on, it goes to protect. I notice that there is a +80V on the other side of this amp, measured after the output inductor.

Can you please give me one more information? how to find the exact part number of the SMD transistor? It's written as AG and DK (SOT), any technique to get the part number? I broke one of this transistor. I'm planning to order it today, im so very cautious and the list must be complete. It takes a couple weeks and costly when ordering this parts offshore.

thank you so much!

I will try to contribute as I can...I have complete schematics of JL brands, electtromedia/audison amps...

[Perry Babin]

Please email me
babin_perry@yahoo.com

This site has many of the codes:
The SMD Code Book

AG is likely a 2SA1797
DK is likely a 2SC4672

[nonprof]

Originally Posted by nonprof

thanks! for having these numbers.
.
do you have an idea what is the problem? the first problem of this amp is when the relay turns on, it goes to protect. I notice that there is a +80V on the other side of this amp, measured after the output inductor.

Can you please give me one more information? how to find the exact part number of the SMD transistor? It's written as AG and DK (SOT), any technique to get the part number? I broke one of this transistor. I'm planning to order it today, im so very cautious and the list must be complete. It takes a couple weeks and costly when ordering this parts offshore.

thank you so much!

I will try to contribute as I can...I have complete schematics of some brands...

[Perry Babin]

Those driver boards have a lot of problems. The smaller transistors often short or become leaky. The small 470 ohm resistors often open or drift in value. Bad solder connections are common on many of the transistors.

If it's going into protect as the relay clicks, it's likely due to having DC offset on the output transistors. That can be caused by virtually any component on the driver board but most commonly due to an open resistor or defective transistor.

[nonprof]

Originally Posted by Perry Babin

Those driver boards have a lot of problems. The smaller transistors often short or become leaky. The small 470 ohm resistors often open or drift in value. Bad solder connections are common on many of the transistors.

If it's going into protect as the relay clicks, it's likely due to having DC offset on the output transistors. That can be caused by virtually any component on the driver board but most commonly due to an open resistor or defective transistor.

thanks! Ill check all of these...