What if i unsolder all the output transistors (B778 and D998)? Maybe they are shorted?
is it worthwhile?
On The pcb i checked them with ohmmeter they seem to be ok
is it worthwhile?
On The pcb i checked them with ohmmeter they seem to be ok
If the supply doesn't draw excessive current with the rectifiers out of the circuit, it would seem to indicate that the problems is on the secondary side of the power supply. There is no current flowing through the outputs if they are not getting hot and you read 0.000v across all of the large white resistors. The rail caps or a solder bridge/loose strand of wire seem to be the only things left that could cause excessive current draw.
You originally stated that the FETs were heating up but was that the reason for removing the amp from the vehicle?
Also, if the voltage is dropping as low as 7 or 8v (measured across B+ and ground), that would limit the drive voltage which could make the FETs overheat.
You originally stated that the FETs were heating up but was that the reason for removing the amp from the vehicle?
Also, if the voltage is dropping as low as 7 or 8v (measured across B+ and ground), that would limit the drive voltage which could make the FETs overheat.
the reason my friend pulled out the amp from the vehicle was that amp doesn't power on.When i connected the amp to my power supply i noticed the FETS overheating
I think this is getting a bit tricky for my little experience on car amps.
In the past i had the same problem with mine mosfet car amp (different brand) and the FETS was overheating and the problem whas a resistor befor the FET.
I will pull out the electrolytic capacitors. Is it possible one of them be shorted ?
I think this is getting a bit tricky for my little experience on car amps.
In the past i had the same problem with mine mosfet car amp (different brand) and the FETS was overheating and the problem whas a resistor befor the FET.
I will pull out the electrolytic capacitors. Is it possible one of them be shorted ?
It's extremely rare for the rail caps to short but it can sometimes happen.
What are you using as a power supply to power this amp?
Is the voltage dropping to 8v across the B+ and ground terminals with only 1.6 amps of current draw?
What are you using as a power supply to power this amp?
Is the voltage dropping to 8v across the B+ and ground terminals with only 1.6 amps of current draw?
I am using a computer power supply. I have used it to power up a couple of amps in the past with no problem.
I don't know what the voltage drop is across B+ and ground. I will post you tomorrow
The Amps are 1,6
I don't know what the voltage drop is across B+ and ground. I will post you tomorrow
The Amps are 1,6
Measure the DC voltage across the power supply's 12v output before and after connecting the amp.
How did you measure the 1.6 amp current draw?
How did you measure the 1.6 amp current draw?
Hi
Voltage without the amp connected is 11,5
Voltage with amp connected is 9,6
I connect the multimeter in series with my power supply and +B amplifiers connector and with power on i get 1,6 Amps
Voltage without the amp connected is 11,5
Voltage with amp connected is 9,6
I connect the multimeter in series with my power supply and +B amplifiers connector and with power on i get 1,6 Amps
The low voltage could be the reason that the FETs are heating up. I think you should check this with a supply that can maintain at least 12v with the amp connected to see if the FETs still run hot.
I used a bench power supply at 13,5 volts and problem remains
The FETS are heating again
The amp draws 1,8A and the voltage drops to 9
The FETS are heating again
The amp draws 1,8A and the voltage drops to 9
I didn't believe in my eyes. Look what i found at the pcb(photo below).
The parts are P30N06
How can this be done? Maybe someone did it ?
Stupid me i didn't see it from the beginning.
I soldered the cut pcb, i powerd up the amp and now it draws 6,8 Amps with 5 Volts at +B terminal and ground
The parts are P30N06
How can this be done? Maybe someone did it ?
Stupid me i didn't see it from the beginning.
I soldered the cut pcb, i powerd up the amp and now it draws 6,8 Amps with 5 Volts at +B terminal and ground
Attachments
Those generally only burn when the FETs fail but if you had about 5v on the gates of the FETs, the FETs have likely survived.
Remove the rectifiers again to see if the power supply will operate normally and draw only about 1 amp.
If it does, you'll need to reinstall the rectifiers and check to see if any of the outputs are getting hot.
Remove the rectifiers again to see if the power supply will operate normally and draw only about 1 amp.
If it does, you'll need to reinstall the rectifiers and check to see if any of the outputs are getting hot.
With rectifiers out of the pcb amp draws 12.8 A !!!
No voltage at +B
There is a short circuit as i can imagine somewhere
No voltage at +B
There is a short circuit as i can imagine somewhere
If you have 0v across the B+ and ground terminals, you likely have either shorted FETs or a solder bridge from drain to source on the FETs.
Can you say if it is necessary to change the P30N06 FETS or only the BUK 456 ?
If yes is the 60NF06 equivalent?
If yes is the 60NF06 equivalent?
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