ALPHASONIK PMA4075

[S Merlington]

This amp is wierd i have 10.50 volts on every leg of every single op-amp..

I have 10.50 volts on all 3 legs of every output..

Heres what i have on the 494

Pin 1:0
Pin 2:0
Pin 3:0
Pin 4:0
Pin 5:0
Pin 6:0
Pin 7:0
Pin 8:13.89
Pin 9:0
Pin 10:0
Pin 11:13.89
Pin 12:0.78
Pin 13:0.16
Pin 14:0.16
Pin 15:0.05
Pin 16:0

Any ideas?

 

[Perry Babin]

There is likely 0v instead of 10.8v. Use one of the non-bridging speaker terminals or the secondary center-tap of the power transformer as the reference (black probe).

Pin 12 has to have at least 7v (will generally be approximately 12v) for the IC to operate. Determine why there isn't enough voltage on pin 12.

 

[S Merlington]

Ok found a broken trace on the botton side of the board amp powers up perfectly now