KICKER ZX1500.1D No power, No Relay, Protection..

[rhempz01]

So a zx series came in today stuck into protection. Removed the rectifiers to test jīthe po
I have checked all the mosfets, drivers ect. And tried lifting d7, and pulling the class d card. No change.
I checked the c6, c12, c11 all test good (in curcuit) 110nF
Q110,Q111 - no short there.
The only components b i noticed damaged were the 100R wire wound resistors R63,R66 were badly burnt.
Some help would be most welcome.

 

[PapaZBill]

Post pic's of the board. Top side (with and w/o the preamp)and bottom side if you have pulled out of chassis, and close up of preamp board. Partly because I need to know what rev the amp is, and there may be something another pair of eyes can see.

Check ohms between Power and speaker grounds.

Do the 100ohm R63 and R66 check okay?

 

[rhempz01]

I changed both the R66,R63 the ones in the amplifier were burned but still within tolerance.

Speaker ground and main ground is open.

Rectifiers are removed.

 

[rhempz01]

Pcb

 

[rhempz01]

Class D card.

 

[rhempz01]

Bottomside

 

[PapaZBill]

I need to check my notes when I get back to the office.

 

[PapaZBill]

Measure the DC voltages around U1 and U2 using Power Ground for the black probe. Also DC voltages around U3 using the -speaker terminal for the black probe. You will have to remove the class D card to get to U3. Post your results as below for all IC's


U1 and U2
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

U3
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

 

[Perry Babin]

PapaZBill:

I don't know how you're posting the things that you have to post repeatedly but using a macro program like ShortKeys makes it much quicker.

 

[rhempz01]

U1
Pin 1) .003
Pin 2) 4.993
Pin 3) .051
Pin 4) .036
Pin 5) 1.511
Pin 6) 3.507
Pin 7) .002
Pin 8) 11.54
Pin 9) 4.439
Pin 10) 4.439
Pin 11) 11.50
Pin 12) 11.50
Pin 13) 4.995
Pin 14) 4.994
Pin 15) 4.994
Pin 16) .002

U2
Pin 1) 4.889
Pin 2) 3.355
Pin 3) 4.841
Pin 4) .198
Pin 5) 1.487
Pin 6) 3.414
Pin 7) 0.00
Pin 8) 0.00
Pin 9) 0.00
Pin 10 0.00
Pin 11) 0.00
Pin 12) 12.05
Pin 13) 5.010
Pin 14) 5.011
Pin 15) 5.010
Pin 16) 3.838

U3
Pin 1) .006
Pin 2) .007
Pin 3) .007
Pin 4) .007
Pin 5) .008
Pin 6) .003
Pin 7) .0065
Pin 8) .003
Pin 9) .002
Pin 10) .012
Pin 11) .008
Pin 12) .032
Pin 13) .002
Pin 14) .008

 

[rhempz01]

I need to repost u3 I used the wrong ground

 

[rhempz01]

U3
Pin 1) .002
Pin 2) .000
Pin 3) .000
Pin 4) .030
Pin 5) .063
Pin 6) 1.606
Pin 7) 0.00
Pin 8) 1.499
Pin 9) 1.583
Pin 10) 0.00
Pin 11) 0.00
Pin 12) 0.00
Pin 13) 0.00
Pin 14) -.014

 

[PapaZBill]

U3-74HC74 is looking at +OCP,-OCP and DC Protect. Pin 4 is held high(5v) normally, keeping Pin 6 high. If any of the three is asserted high, Pin 4 goes low which in turn forces Pin 6 low.

I suspect that one or more of Q8,Q18,Q19,Q20-2N4401 have failed/shorted. Check all four with an ohmmeter in circuit and replace.

Q101-MPSA92 or Q111-MPSA42 may have failed. Check and replace if neccesary.

 

[rhempz01]

D7 was lifted for those measurements..
U3
1.) .015
2.) 0.00
3.) 0.00
4) .001
5) .000
6) .016
7) .000
8) .000
9) .000
10) .000
11) .000
12) .000
13) .000
14) .005

 

[PapaZBill]

Where you using power ground for black probe when D7 was listed?

Have you checked Q8,18,19,20 yet? Q101,Q111?

 

[rhempz01]

I replaced them all no change. No power. No drive, rectifiers removed. D7 in curcuit.

No speaker - terminal.

 

[rhempz01]

Post #14 was made after I reinstalled D7 and tested the 74HC74 flip flop.
I changed all the parts in question just for good measure. l tested them and confirmed them good.
I have also removed all the output transistors to check them all. All are good.
Still the amplifier remains in protection.

 

[PapaZBill]

Have you replaced U3?

 

[rhempz01]

No. I can try that.

 

[rhempz01]

I can't seem to find the 74hc74 here anywhere. I know I have them. Anyway I ordered some from arrow they should be here in a few days. Anything else that it could possibly be?