Kicker KX650.4 randomly cuts out

[ComputerJLT]

Alright guys, i'm working on a kx560.4 for a guy. it powers up and sounds fine but will randomly shutoff and come back on. Tried on a bench supply with low output and also in a car at high output (not overloaded, bridged/unbridged doesn't matter). There was no pattern with vibration or input voltage. Also current never fluctuated before it cut off. When it shuts off the power light slowly dims and the rail caps drain; then it comes back on just like you reapplied power to the remote lead. when you remove power from the remote lead the power light abruptly shuts off and output stops and the rail caps drain much more slowly (maybe a bleed resistor in there somewhere)

I found the remote lead was loose on the pcb, i re soldered it and even ran a jumper to another joint on the remote trace to make sure and it still does it. I've scoped the power supply and all the waveforms look good; i've tapped on the trafo and various caps/transistors and can't get it to shutoff. it just does it when it wants to.
One thing i did notice when it shuts off, the power supply fets loose their input on the base pin causing them to stop switching the trafo. i tried tracing farther back in the circuit but then the amp decided to not act up.... go figure

Anyway i've given up for the night and thought i'd post here and see if anyone has any advice on this situation.

[Perry Babin]

Post the DC voltage on all pins of the power supply IC when it shuts down.


Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:

[ComputerJLT]

should I measure them from the negative battery terminal or from the negative unbridged speaker terminal(s)?

[Perry Babin]

negative battery terminal

[ComputerJLT]

ok; i messed with the amp a bit tonight but i could not get it to shutoff (applied/removed remote lead a number of times it kept working normally. I did measure the voltages with it working just as a reference. These measurements were taken with the negative lead on my cheapo DMM on the negative batt terminal with the amp on and playing at a low enough level to not tax my 3a radio shack power supply.

Pin 1: 4.1
Pin 2: 4.97
Pin 3: 4.97
Pin 4: 4.97
Pin 5: 9.17-9.38 varried but not volume dependant
Pin 6: 7.68
Pin 7: 3.05
Pin 8: 3.1
Pin 9: 1.06
Pin 10: 3.31
Pin 11: .06
Pin 12: 0
Pin 13: 1.46
Pin 14: 3.33
Pin 15: 0
Pin 16: 7.55

none of the pins were scoped just dmm'd, i did notice yesterday with my scope one of the pins had a sawtooth wave form on it about probably 1-2v peak

[Perry Babin]

The pin numbering is wrong. It appears that you have 16-9 then 1-8. Look up the datasheet for the IC for the pin numbering scheme.

[ComputerJLT]

yea i was looking at it all wrong lol....

the amp seems to have fixed itself or the loose remote lead was teh culprit. It would not cut out on me again and the owner picked it up.

Thanks for your help though Perry!