RF 400x4, output channel distortion - Page 2

Perry Babin · 7th July 2010, 10:04 PM

sulaiman b · 8th July 2010, 03:26 PM

Thanks Perry,

I managed to remove the transistor and it seemed to be working at it should, I had a reading from both the outer legs when the middle was connected to the ground on the multimeter diode test.

When the legs were switched so the positive is on the middle leg there was no reading when the negative was on the outer two legs.

And when both the outer legs were tested against eachother the circuit remained open

So I have placed an order for the resistors and will let you know how I get on

Cheers

sulaiman b · 29th August 2010, 12:25 PM

Ok guys, sorry for the late update, the supplier of the resistors was out of stock until last week and I have just soldered the replacement resistor in.

The problem still remains, with the resistance on the rear right channel showing 1.22 and steadily increasing.

Anyone able to tell me what to check next?

Perry Babin · 29th August 2010, 06:28 PM

List all parts that you have already replaced.

Check the following:
Q312
Q313
R363
R336

7th July 2010, 10:04 PM	#11
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Vishay \| Passives \| Resistors \| Surface Mount, Fixed \| Thick Film - 0805 \|CRCW080510R0FKEA They don't stock the MPSA56 but the following transistor should work. ON Semiconductor \| Semiconductors \| Discretes \| General Purpose Transistor \| PNP Small Signal \|MPSA92G __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

29th August 2010, 06:28 PM	#14
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	List all parts that you have already replaced. Check the following: Q312 Q313 R363 R336 __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

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8th July 2010, 03:26 PM	#12
sulaiman b diyAudio Member Join Date: Jul 2010 Location: London, UK	Thanks Perry, I managed to remove the transistor and it seemed to be working at it should, I had a reading from both the outer legs when the middle was connected to the ground on the multimeter diode test. When the legs were switched so the positive is on the middle leg there was no reading when the negative was on the outer two legs. And when both the outer legs were tested against eachother the circuit remained open So I have placed an order for the resistors and will let you know how I get on Cheers

29th August 2010, 12:25 PM	#13
sulaiman b diyAudio Member Join Date: Jul 2010 Location: London, UK	Ok guys, sorry for the late update, the supplier of the resistors was out of stock until last week and I have just soldered the replacement resistor in. The problem still remains, with the resistance on the rear right channel showing 1.22 and steadily increasing. Anyone able to tell me what to check next?

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