This amp go to protect sometimes, then turn HU off and on i amp power up without problem. And this is only when car motor is runing. On key off, amp dont go in protect. But, few days earlier amp go to protect independently of motor runing or not, and can't power up amp with key off/on. I disconect the power wire, ground and speaker, and nothing changes. Move ground wire to another places and still same thing. Sometimes it power on and runing nice but in most cases it go to protect. I notice a strange boop sound from woofer when amp go to power on, and same thing on power off, when it's working. 
So i decide to open amp and check whats hepening. It have tl494cl IC, jrd4558d opamp, irf3205 mosfets, and tip35c and 36c transistors and u1620 and u1620r Rectifiers. I have a bad ground connection on rca's and not good connection on one leg of 3205 fet. Amp didn;t go to protect. One day its plaing nice and over night still the same thning.
Opened amp again. Check everything and i dont find a problem. Disconnect rectifiers and 35/36c tranzistor, power on amp and got protect mode. Put it back on board and amp turn on like charm. It's working about a 20-30min and amp everything was cold like an ice cream.
tl494cn voltage on pinout.
pin1 1.14
pin2 3.4
pin3 0.6
pin4 0
pin5 1.5
pin6 3.3
pin7 0
pin8 8.8
pin9 3.6
pin10 3.6
pin11 8.9
pin12 12
pin13 4.9
pin14 4.9
pin15 4.9
pin 16 0
Is that ok?
I will tomorow change all of capacitators on board. From left to right. I think that boop sound from woofer on amp on/off is becouse of them. Am i right?
And how to find a problem why amp go to protect, more often on 14volts with enging runing and sometimes on 12volts when car is off. And usuly go in protect in the mornig when car not runing some time. Pint me in some direction i have try everything.
So i decide to open amp and check whats hepening. It have tl494cl IC, jrd4558d opamp, irf3205 mosfets, and tip35c and 36c transistors and u1620 and u1620r Rectifiers. I have a bad ground connection on rca's and not good connection on one leg of 3205 fet. Amp didn;t go to protect. One day its plaing nice and over night still the same thning.
Opened amp again. Check everything and i dont find a problem. Disconnect rectifiers and 35/36c tranzistor, power on amp and got protect mode. Put it back on board and amp turn on like charm. It's working about a 20-30min and amp everything was cold like an ice cream.
tl494cn voltage on pinout.
pin1 1.14
pin2 3.4
pin3 0.6
pin4 0
pin5 1.5
pin6 3.3
pin7 0
pin8 8.8
pin9 3.6
pin10 3.6
pin11 8.9
pin12 12
pin13 4.9
pin14 4.9
pin15 4.9
pin 16 0
Is that ok?
I will tomorow change all of capacitators on board. From left to right. I think that boop sound from woofer on amp on/off is becouse of them. Am i right?
And how to find a problem why amp go to protect, more often on 14volts with enging runing and sometimes on 12volts when car is off. And usuly go in protect in the mornig when car not runing some time. Pint me in some direction i have try everything.
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
and some from google
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
keep trying to attach images but it frozen on waiting to ww.diyaudio.com to response and nothing happens 15 minuts. Don't know why. Lets try this way. Link to gallery.
amp — Postimage.org
amp — Postimage.org
The caps were almost certainly not the problem but if you removed the brown fixative that was in contact with other components, that could have fixed the problem.
38v with 50v rail caps is OK. I don't know that the rail voltage is supposed to be.
Was it shutting down on the 12v supply before you did anything to it?
38v with 50v rail caps is OK. I don't know that the rail voltage is supposed to be.
Was it shutting down on the 12v supply before you did anything to it?
Ok. amp works well in car on 12v and 14v. Then sudenly go to protect on 12v and same one 14v. Pull amp from car and put in power suply and have this messurement:
tl494 on 12v and protect
pin1 1.27v
pin2 4.05v
pin3 4.70v
oin 4 0v
pin 5 1.46v
pin6 3.29v
pin7 0v
pin8 10.98v
pin9 0v
pin10 0v
pin11 10.98v
pin12 11.71v
pin13 4.94v
pin14 4.94v
pin15 4.94v
pin16 7.14
Voltage on speaker terminals are 0.04v, messured on + and - speaker terminals.
Voltage on power fets 12v
voltage on positive and negative rectifiers are 0.54 and 0.12v
Voltaage on transistors are same as on rectifiers.
So what can be my problem?
tl494 on 12v and protect
pin1 1.27v
pin2 4.05v
pin3 4.70v
oin 4 0v
pin 5 1.46v
pin6 3.29v
pin7 0v
pin8 10.98v
pin9 0v
pin10 0v
pin11 10.98v
pin12 11.71v
pin13 4.94v
pin14 4.94v
pin15 4.94v
pin16 7.14
Voltage on speaker terminals are 0.04v, messured on + and - speaker terminals.
Voltage on power fets 12v
voltage on positive and negative rectifiers are 0.54 and 0.12v
Voltaage on transistors are same as on rectifiers.
So what can be my problem?
The attached diagram is similar in layout but the designations and values are different.
The first thing you need to be able to do is to make it go into protect reliably. Otherwise, disabling the protection circuit may not help much.
To disable the protection circuit, find and remove the equivalent of R25 from the circuit.
Do whatever you did to force the amp into protection. Does it work perfectly doing whatever you did to cause it to go into protect or does it malfunction in some way when it would normally be in protect?
The first thing you need to be able to do is to make it go into protect reliably. Otherwise, disabling the protection circuit may not help much.
To disable the protection circuit, find and remove the equivalent of R25 from the circuit.
Do whatever you did to force the amp into protection. Does it work perfectly doing whatever you did to cause it to go into protect or does it malfunction in some way when it would normally be in protect?
if i do it right its a r256 and r155 on my board. With r155 removed, no protection, only strange sound from the speaker. With r256 removed i got protection mode. Same with r154 and r255. So, with removed r256 i got protection. Same with r154. Thats resistors are for negative channel.
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