It's likely the same as the TL431. The IC is used like a zener diode. If you measure the DC voltage between the anode and the reference terminal and the voltage is 2.5v, the IC is likely working properly.
Do you know how to check for leakage in the transistors?
Do you know how to check for leakage in the transistors?
Spzzztk, ok i will check that! But they worked before
i placed the transistors in the wrong order.
But its worth checking.
Perry, taught so.. bought some new but i will
check them as you described!
I know how to check them the way described
at bcae1.com. 🙂 Both the drivers and the outputs
read OK.
Strange thing is that to much current is passing
through the amp, and both drivers and outputs are
out of the board.
The resistors did not get that hot with no load before!
I can cook a beef on them 😉
Any tips what could have blown when i swaped the
drivers? Could be hard without schematic maybe.
Im waiting in patience for them =)
i placed the transistors in the wrong order.
But its worth checking.
Perry, taught so.. bought some new but i will
check them as you described!
I know how to check them the way described
at bcae1.com. 🙂 Both the drivers and the outputs
read OK.
Strange thing is that to much current is passing
through the amp, and both drivers and outputs are
out of the board.
The resistors did not get that hot with no load before!
I can cook a beef on them 😉
Any tips what could have blown when i swaped the
drivers? Could be hard without schematic maybe.
Im waiting in patience for them =)
Here are some basic checks to do:
are there any bulged capacitors or capacitors with shrunken plastic? i would check all the caps for shorts and for value if possible. also check all of your diodes for shorts or opens. check resistors for opens and out of tolerance vaues while your in there. also look for signs of heat damage on solder joints on the bottom of the board and remove all of the old solder and re-solder. also resolder any spots that look like cold solder joints or have rings around the solder joints(oxidation)
are there any bulged capacitors or capacitors with shrunken plastic? i would check all the caps for shorts and for value if possible. also check all of your diodes for shorts or opens. check resistors for opens and out of tolerance vaues while your in there. also look for signs of heat damage on solder joints on the bottom of the board and remove all of the old solder and re-solder. also resolder any spots that look like cold solder joints or have rings around the solder joints(oxidation)
Sorry for digging in dead threads 😛, but here's another "solution":
The C350 works after power on fine for about 15 seconds. Then it switches to red protection mode and no more sound
While the protection mode in this model C350 only cut's off the speakers from signal and not stop the whole amp from working (this would be a real protection) I deceided to not search for the error in the faulty protection module but to brigde the contact's at the relay and disable on this way cutting of the speakers. 😱 Works! 😀
The C350 works after power on fine for about 15 seconds. Then it switches to red protection mode and no more sound
While the protection mode in this model C350 only cut's off the speakers from signal and not stop the whole amp from working (this would be a real protection) I deceided to not search for the error in the faulty protection module but to brigde the contact's at the relay and disable on this way cutting of the speakers. 😱 Works! 😀
In my amplifier ( nad C352) I had the same protect problem. I think it was a connection problem in PSU. Whatever solved.
There is two control in protect circuit (chip-UPC1237), one is, using a diode and resistor, it control the voltage from the PSU, only one diode ac rectifier and a small capacitor in parallel and resistor gives information from psu to protect circuit (on chip pin 4).
Second one control the output of amplifier if it's in the normal limits it open the output relay (pin 1&2).
my problem I think some connection error at diode or resistor. I can give one advice about PSU, you can measure + and - voltages. if it's different some volts you have to control psu circuit. Simply without search, change rectifier diodes 🙂 may be solved or not.
There is two control in protect circuit (chip-UPC1237), one is, using a diode and resistor, it control the voltage from the PSU, only one diode ac rectifier and a small capacitor in parallel and resistor gives information from psu to protect circuit (on chip pin 4).
Second one control the output of amplifier if it's in the normal limits it open the output relay (pin 1&2).
my problem I think some connection error at diode or resistor. I can give one advice about PSU, you can measure + and - voltages. if it's different some volts you have to control psu circuit. Simply without search, change rectifier diodes 🙂 may be solved or not.
wow! 😀 it was a long time ago i started this thread. i probably got my nad working, i cant remember. so many years ago 😀
Please don't post in a repair thread that was started by someone else unless you are trying to help them.
Start a new thread if you need help with a repair of your own.
http://www.bcae1.com/temp/newthreaddiy01.png
Start a new thread if you need help with a repair of your own.
http://www.bcae1.com/temp/newthreaddiy01.png