Sundown SAZ3000

[mike49504]

I got another one of theese amps in for repair. The problem im having with the amp is when i power it up i can hear the relay click on but no power light . also the amp has no output.

Here the voltages i have.

LM393
1:.11
2:2.56
3:.04
4:0
5:1.69
7:0.11
8:13.62


7815
1:0
2:0
3:-.08

7915
1:0
2:-24.7
3:-14.8

7805
1:-0.8
2:0
3:-.03

7905
1:0
2:-14.8
3:-4.8

KA78T12
1:-87.4
2:-119.7
3:-119.8

Any ideas on what to check?

[Perry Babin]

Do you have positive rail voltage? Defective rectifier?

[mike49504]

I have both + - rail voltages 119 volts

I have + 15 volts but -.04 for the negative regualted voltages

[Perry Babin]

There isn't any positive DC on either of the positive regulators. Follow the circuit back from leg 1 to see if there's a broken leg on a diode or some other break in the circuit.

[mike49504]

I found a broken capacitor The color bands on it are Yellow Black Brown
Is that the same thing as a 0.1 uf mylar cap? (104)

[Perry Babin]

It could be.

[mike49504]

The 7815 is also defective.

The one thats in the amp is marked Kia 7815A And the package style is where you dont need mica insulators behind it But the regulator is standing straight up in the middle of the board.

I have the following parts 7815act and a LM7815AC both T0 220 package will either of thoose work?

[Perry Babin]

I don't know what the 't' signifies but I'd suspect that either would work.

[mike49504]

Replaced the 7815 and still no + voltage on the regualtor so i tracked it back to the output driver board . Is there anything you know of on thoose boards that goes bad and makes it so theres no = voltage on the regulators?

[Perry Babin]

Do you have input voltage on the regulator but no output voltage?

Are you measuring the voltage with the black probe on the center leg of the regulator?