Kicker ZX450.2

[m4ick]

R55 and R56 are burned and cannot be read. They each tie the middle leg of a TIP41C or TIP42C to the rails respectively. Any idea what their values may be? It appears to possibly be the voltage regulator circuit.

[m4ick]

ZD4 appears to be near 0 ohms while ZD5 reads 950 in one direction (diode check) and OL in the other. Could the one shorted zener burn the resistors in both + and - voltage regs?

[m4ick]

Uh oh, just found an op amp cracked in half. It all op amps read 340 from vcc+ to vcc- on diode check. I'll remove the one op amp and see if it corrects the leak.

I don't have a 2068D on hand, would a 4558P suffice for testing?

[m4ick]

OK, new summary.

Voltage regs are shot with one shorted zener on one side and R55 and R56 are burned, one in each regulator.

I found a blown op amp that made all op amps read 340 both ways from vcc- to vcc+. With the burned op amp removed I place the + probe on VCC- and negative on VCC+ and get about 640 on diode check, with them reversed i see a cap charging and it reaches OL eventually. Much improved over 340 both ways. These tests were done with the op amp board disconnected from the amp.

At this point I need the value of R55 and R56 in the voltage regulator, I cannot read them at all. I also need to know if I can replace a 2068D with a 4558P so I can test this thing.

[Perry Babin]

Email or call kicker for the value of the resistors.

The 4558 may work but you should use an exact replacement if you're repairing this for a paying customer.

[m4ick]

Ok, will email or call kicker. The regulators have 3.3k ohm resistors and then the burned ones. My best guess looking at other amps is 100ohms for the burned resistors, but I will find out for sure.

I figured the 4558 would work but the 2068 is newer technology and has better specs, I plan on repairing the regulators (should have all parts on hand) and testing to see if any other op amps have failed. Then testing with the 4558 for output. Then I will order some 2068s and parts for the MTX 81000D.

And yes, this one is for a paying customer.

One last thing, if I replace the resistors and the shorted zener is it safe to power it up to determine if the TIP41/42Cs are operating correctly or would it possibly destroy more op amps?

EDIT: I can leave the crossover/gain board out of circuit for testing on the regs.

[Perry Babin]

IF the Zeners are in the circuit, it should be safe to power the amp up if the TIP transistors are not leaking badly or shorted.

[m4ick]

Still waiting to hear back from kicker.

This photo is from the Kicker KX350.2. The part designations are the same as in the ZX450.2. I have replaced R55 and R56 with 10ohm resistors but what are the diodes? All I can make out is the number 15 and the number 2 which I imagine means is just a 15v zener, would a 1n4744 work in its place?

[m4ick]

Kicker just emailed me a list of components for this amp, would you like me to e-mail it to you Perry?

R55 and R56 were 10ohm 1/4w, I had some wire round 10ohm resistors on hand, and the zeners are NEC RD15EB3 0.5W 15V, replaced them with 1N4744A (1W equivalent).

I now get +-14.8, installed the crossover/gain board and it did not draw excessive current or heat up, I installed a 4558 in place of the 2068 and voila! Audio! All I need now is some 2068s and this thing is done!

Again, let me know if you would like me to e-mail you the component list for this amp.

[Perry Babin]

Yes.

babin_perry@yahoo.com