kicker xs100

[timwebb]

I have one of these amps to repair.the problem is there is a short between the first and the last legs on the output transistors. I removed all output transistors and a few shorted tip42. And I removed the rectifiers. There is a short between the second and third leg.

 

[Perry Babin]

Do you read less than 1 ohm between legs 1 and 2 of the outputs?

Or are you reading that on the board with the outputs out of the circuit?

 

[timwebb]

all the output tested good. and that reading was on the board with no transistors in the circuit.

 

[Perry Babin]

Do you read less than 1 ohm from 1-2 on the board?

If not, what is the resistance that you read?

 

[timwebb]

tip35- 6.3k
tip36-10k

 

[Perry Babin]

Sorry, that should have read 1-3 (where you read the 'short').

 

[timwebb]

21 ohms

 

[Perry Babin]

That's not a short. If you look at the components, I think you'll find a 22 ohm resistor connected between the traces that go to the base and emitter of the output transistors.

 

[timwebb]

ok i got the amp powered up and idles.when i connect a speaker it draws a ton of current but nothing get warm

 

[timwebb]

this is what i get on the tabs of the transistors.im getting this one every thing
v/div 1 time/div 5

 

[Perry Babin]

5 what (ms, us)?

What was the input signal?

If you touch the scope probe to the B+ terminal of the power supply, does the trace deflect beyond the top of the display?

 

[timwebb]

5us.
no input signal
no
i was checking for rail voltage there is none.

 

[Perry Babin]

If this amp is like most of the older kicker amps, the rail voltage is on the emitters.

 

[timwebb]

the chip sg3525adw is getting a little to warm and now its putting out a bad driver signal.

 

[Perry Babin]

They run hot when driving the FETs directly. Are there driver transistors between the IC and the power supply FETs?

What does the signal look like directly on the IC output pins?

 

[timwebb]

i dont see any drive transistors. a did a continuity check and the gate resistors runs straight to the ic.

 

[Perry Babin]

Does your 12v power supply have adjustable voltage?

If so, reduce the voltage to about 10.5v and check the signal again.

 

[timwebb]

i used another ps i got. the signal got worse. i get 1.17v on the gate resistor.

 

[timwebb]

it has 29v dc on the speaker terminals. it pushes the speaker out.

 

[timwebb]

i removed all output transistors and still have 29v at the speaker.