Team Cactus 7kw

[Perry Babin]

Follow the circuit back from the bases of the D1302s. It will likely go back through a resistor or two and possibly to an A1381 (transistor).

If that's true, follow the circuit back from the base of the A1381. What drives that transistor?

 

[Perry Babin]

You stated that the square wave on the outputs is switching on and off. Does the current draw decrease when it's off?

 

[mike49504]

NO

 

[mike49504]

The base of the A1381 appears to be driven by the A1266 i removed

 

[mike49504]

OPPPSSS followed the wrong leg back .

The A1381 is driven by a C1027 Transistor heres the voltages on it

Leg1:0.00
Leg2:7.25
Leg3:0.00

 

[Perry Babin]

Have you noticed any of the FETs (audio or power supply) heating up?

 

[mike49504]

No they all remain cool But i do have a limiter in line im afraid not to use it

 

[Perry Babin]

Is the voltage on the collector of the C1027 constant?

 

[mike49504]

yes

 

[Perry Babin]

Remove the C1027. Does the square wave remain constant?

If so, is it leaky?

 

[mike49504]

I removed the C1027 and the square wave still doesnt remain constant

 

[mike49504]

The voltages on the A1381 are pulsing also

 

[Perry Babin]

Remove the A1381.

 

[mike49504]

The square wave is still pulsing with the A1381 and C1027 removed .

Also the voltages on the rectifiers is pulsing

 

[Perry Babin]

Is the power supply remaining on? Look at the square wave on the drain/tab of the power supply FETs.

 

[mike49504]

In the first pic is leg 1 of the fet 2nd pic is middle leg of fet and the 3rd leg just deflects. Square waves remain constant

 

[Perry Babin]

OK. That seems to eliminate the protection components on the main board.

On the audio driver board, on the center row of pins, one end pin has 15v. Sso you know that you have the right pin, confirm that it has 15v. On the other end of that row, do you see a pulsing output?

 

[mike49504]

Every pin on the middle row of pins is pulsing voltages

 

[Perry Babin]

Do you have both positive and negative rail voltage?

Do you have the proper output voltage on all of the regulators? Place the black probe on the 'ground' pin of each regulator when measuring the voltage. The 78xx ground is the center leg. The 79xx ground is the first leg.

 

[mike49504]

7815
1:13.9
3:12.5

7915

2:-.04
3:.-.04