Sundown SAZ 3000 D

[mike49504]

I replaced the rectifiers in this amp due to broken legs. Amp powerd up and produced audio perfectly.


Returned the amp to the customer and he said it was stuck in protection mode so i got the amp back and sure enough its stuck in protection mode.


So i removed the rectifiers and its still in protection so i put thoose back in i removed the output driverboard and no different.

Here what i have on the 494
1:8.67
2:2.62
3:4.92
4:4.29
5:1.51
6:3.78
7:0
8:13.90
9:0
10:0
11:13.89
12:13.89
13:5.08
14:5.08
15:5.08
16:0

Any ideas on what to check?

[ian33]

if you removed the rectifiers and it is still in protect i think the problem is in the power supply area

[Perry Babin]

Can you send me a high resolution photo of the area around the 494 IC (showing all ICs in the area)?

babin_perry@yahoo.com

[mike49504]

Ill see if i have another cord for my camera since the the one i have doent work.

There are no other IC's anywhere near the 494 just a transistor c3198 and caps and resistors

[Perry Babin]

What's driving pin 1 of the 494?

[mike49504]

I found a LM293 at the other end of the board

voltages on that ic are

1:9.28
2:2.55
3:.07
4:0
5:2.17
6:4.12
7:9.28
8:13.89

[Perry Babin]

Does it appear that any of the outputs from that IC are driving pin 1 of the 494?

[mike49504]

doeant look like it.

The C3198 goes to some resistors and then to pin 1 of the 494

The 3198 voltages are
1:4.29
2:5.08
3:4.92

[Perry Babin]

Pin 1 has 8+ volts on it. It can't be coming from the 3198.

[mike49504]

Looks like pin 1 of the 494 goes through some resistors and diodes and then goes to pin 7 of the 293