memphis 1000

[mike49504]

Amp goes into protection. If i pull both driver boards amp will power up normal.

But both not just 1 of the driver boards for the outputs needs to be out for it to power up normal

[Perry Babin]

If there is no DC on the tabs of the output transistors when the driver boards are out of the amp, there's a good chance that you have a defective LM361 comparator.

Did you get your scope back?

[mike49504]

theres no dc on the outputs with boards removed. Wheres the lm361 located on this amp?

[mike49504]

My scope isnt back yet i dont what the heck the guy is doing ill call them tommrow and see where its at

[Perry Babin]

There are likely two DIP ICs on the board behind the RCA jacks. The 14 pin IC is the LM361. Give me the DC voltage on all 14 pins.

LM361
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:

[mike49504]

lm371
1=12.42
2=0
3= -.02
4= -.06
5=0
6= -12.68
7=0
8=2.92
9=.01
10= -1.90
11=0.62
12=0
13=2.93
14=2.93

[Perry Babin]

That doesn't look defective.

Plug one driver board in at a time and see if the tabs of the output transistors swing towards the rails.

[mike49504]

when i put 1 in at a time the output readings are leg 1= 0 middle 25.38 for 1/10 of a second last leg 0

[Perry Babin]

There's something wrong. The tabs of all of the outputs on each side should be directly connected (confirm).

If that's correct, the rail voltage is on the last leg and has to be greater than or equal to the voltage on the center leg. I wouldn't think it possible that the rail voltage could get back down to 0v so quickly that you couldn't measure it. Use the secondary center tap as the reference.

[mike49504]

im gonna put this aside for the night i have to fix another one before the guy comes picks it up