Does anyone have a repair manual for this amp? Or know the layout?
First time owning and working on a 5 channel amp. The sub channel power supply if burnt q35 through q38. The gate resistors are damaged also. They are marked 470. 47 ohms correct?
First time owning and working on a 5 channel amp. The sub channel power supply if burnt q35 through q38. The gate resistors are damaged also. They are marked 470. 47 ohms correct?
Testing irf9640 P channel FET red probe drain black probe source I'm reading .819 on one fet and .732 on 2 other fets. Are they bad?
Testing in circuit or out? I only asked because other components can alter your reading.
sent from an IRFZ48N
sent from an IRFZ48N
470 = 47 ohms (4, 7, and 0x10 multiplier).
The probe orientation is reversed when checking P-channel FETs.
The probe orientation is reversed when checking P-channel FETs.
Yes, i got the test procedure from your website. Are my readings from the drain and source ok or do you think they are defective?
resistors r30 marked 102=1kohm. Value is .431ohms so its bad. How do I determine the watt rating. One side is connected to the source of the PS FETs and amp ground terminal. I cannot trace the other side
Is that .431k ohms? Or .431 ohms? The latter would suggest its bad or something in parallel is shorted.
sent from an IRFZ48N
sent from an IRFZ48N
413.7 ohms. I was in a hurry typing, sorry. There is a another resistor in the circuit r40 which reads .959kohms so I'm thinking its just the r30 resistor thats bad. Also the power supply FETs are removed (this is the sub channel).
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Out of the circuit both r30 and r40 test fine. I cleaned the board up some more and I can see the traces better.
Readings in the 900 range would be a bit high but doesn't necessarily mean it's defective. FETs with higher RDSon specs generally also have somewhat higher readings when checking the intrinsic diode (the 0.4-0.9v readings) compared to the FETs used for power supplies.
Does anyone know what q34 is?
1 pin is tied to ground and a 470ohm resistors (r24).
The other side of r24 is tied to another 470ohm resistor (r34) and a diode (d33) and the signal for the gate
The other side of r34 goes to the another leg of q34
D34 goes to the other leg of q34 and traces back to the gates of the power supply transistors q35 and q36.
1 pin is tied to ground and a 470ohm resistors (r24).
The other side of r24 is tied to another 470ohm resistor (r34) and a diode (d33) and the signal for the gate
The other side of r34 goes to the another leg of q34
D34 goes to the other leg of q34 and traces back to the gates of the power supply transistors q35 and q36.
Brandes was correct about something being shorted. After removing q34 and q33 the resistance of r40 and r30 were the same.
If you post a good quality photo of the area, it will make it easier to help you.
What is the part number on the face of Q34?
What is the part number on the face of Q34?
Well, I've been away a while but have been busy. I got this amp working and sold it to a friend. Today he called me saying that the amp would turn on in phases. After about a minute the sub and rear speakers would turn on and then a few minutes later the fronts would turn on. A quick visual inspection 1 of the power supply FETs for the sub channel was toasted. When it did turn fully on everything sounded ok.
He did say he noticed this the day after he was having trouble with his battery. I'm just curious if the amp was bad and was draining his battery or if its possible it shorted after the jump start.
He did say he noticed this the day after he was having trouble with his battery. I'm just curious if the amp was bad and was draining his battery or if its possible it shorted after the jump start.
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If only one of the power supply FETs failed, it's possible that the amp could have drained the battery. This is uncommon but it happens occasionally.
Did you cut the defective FET out of the circuit?
Did you cut the defective FET out of the circuit?
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