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?

 

[Hexhclass]

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

 

[Perry Babin]

Post or send me a photo of the area around the 293.

 

[mike49504]

My new camera doesnt take the greatest pics sorry

 

[Perry Babin]

I think that 293 may be defective. The positive inputs are lower than the negative inputs. That should make them pull their outputs down but they're high instead.

If you're interested in getting better photos, I'm sure that the camera is capable. If it has a macro mode, you may want to try that for close-ups. Holding a piece of tissue paper about 2 inches in front of the flash will diffuse it so the image is more evenly lit. It's not important here but with a bit of effort, I'm sure it can do better.

 

[luka]

mike
take pictures where there is good light and not to close to what you want to take picture of, unless you have macro

 

[mike49504]

Can i change the 293 to a lm393 ?

 

[Perry Babin]

Yes. They are essentially the same.

 

[mike49504]

Ok cool amp is out of protection mode.

But now it draws excessive current Can not having the output driver board in the amp cause it to draw excessive current??

Wondering because i removed the rectifiers and it powers up and relays kick on

 

[Perry Babin]

With no driver board, it shouldn't draw excessive current. The 100k resistors between the gate and source of the outputs should keep the outputs off and therefor prevent current from flowing through them.

What's getting hot when it's powered up?

 

[mike49504]

Strange I soldered the output driver board back in the amp it powers up and idles perfectly . Rectifiers are in the amp also

 

[luka]

so now it works?