Crossfire amp help please cfa-602

[joesch1999]

.4 ohms

 

[Perry Babin]

If the TLx94 hasn't been replaced, I'd suggest replacing it. Install it in a socket if you have one.

 

[joesch1999]

it's a brand new one as of two weeks ago, I have more should I put another one in?

 

[joesch1999]

Perry I was messing with the amp last night, was checking over the sockets where the 688's go on the other side of the amp there is negative on collector and base of them, and you already know the sockets where the 718's go on the left side of the amp have positive on both sockets

 

[Perry Babin]

With the voltage you posted for the IC, I don't see any reason for it to do what you stated that it was doing (essentially shorting pins 9 and 10 together when power is applied). I'd suggest replacing it. It may not solve the problem but it would eliminate it as a possible fault.

 

[joesch1999]

ok I have the tl out, there is only a 220 ohm resistor separating the ground pin 7 of the ic from the outputs pins 9 and ten, the tl is o/l out of the board, pin 7 and 16 on the tl give a o/l reading on the IC

 

[joesch1999]

I am getting negative 12 volts reading on pins 9 and ten with the n channel drivers out

 

[Perry Babin]

Make sure that you didn't have the black probe on the B+ terminal of the amp.

 

[joesch1999]

yeah i didn't, is a a1268 npn bipolar? I was noticing I transistor that had been replaced before I got the amp from my friend, the base leg is connected right to the negative terminal of the amp and the collector has twelve volts emitter is putting out 7 volts, I don't think a 1268 is biploar maybe I am wrong hard to find data sheets on those korean parts. I am thinking that maybe whoever worked on this amp before used a 1268 in place of a 3198 i think thats the bipolar one, I put a new tl494 in still same voltages the 1268 is in spot q301

 

[Perry Babin]

Didn't what?

An A1266 is a PNP bipolar transistor. The pin configuration is ECB. The collector is likely connected to ground if this is being used as an FET driver.

The 1268 is also a BJT.

 

[joesch1999]

Well got it powered up there was a A1268 were a A1266 was supposed to be and there is a c3200 in the n channel I think it is supposed to be a A1266 as well, it is hooked to pin one of the tl494

 

[joesch1999]

Thanks for your help Perry