Lanzar Optidrive 2150

[ben04srt]

I am repairing this amp and having issues on power supply.
Fets are removed a few resisters were replaved along with 4n25 and lm358.
All 4401 and 4403 drivers were replaced.
i have no drive for pin 14 on sg3525.

voltages on 3525
1: 0.920
2: 1.022
3: 0.015
4: 0.209
5: 2.086
6: 3.780
7: 2.12
8: 4.82
9: 4.89
10: 0.062
11: 2.593
12: 0.006
13: 3.615
14: 0.042
15: 13.46
16: 5.10

The scope signal on pin 11 is attached.

 

[Perry Babin]

Are you sure that your scope can display a square wave at this frequency?

What's the resistance pin 11 to pin 12?

Pin 14 to 12?

 

[ben04srt]

Pin 11 to 12. 1.96k
12 to 14. 0.8
I will have to play with the settings on the scope or check another working amp to see.

 

[Perry Babin]

If there isn't a solder bridge between 12 and ground, the IC is likely defective.

If you attempt to remove the IC, clip the leads at the body of the IC, remove the body and then desolder the legs without touching the board with the tip of the iron (heating the leg from the IC only). Add new solder if the leads don't come out easily. These boards are EXTREMELY easy to damage. Avoid touching the pads on the board if at all possible.

 

[Perry Babin]

Like this.

 

[ben04srt]

I bought a new sg3525 so I will install and see if it fixes my issues.

 

[Perry Babin]

Take a photo of the traces under the IC while it's out in case you have one that unknowingly gets damaged when working on the board.

 

[ben04srt]

Amp is up and running again.
I will definetly agree those boards are very easy to damage.
Thanks for the help.