close ups of what? I sent close ups of the ICs, which I suspect. Most other components I have tested and all components look fine.

 

With power applied to the board, what voltage are you getting from the right 2 pins then the left 2 pins?

Common (black) meter probe on ground, meter the left 2 then the right 2.

You should have voltage on all four pins of both devices.

If you have none, that part is not the problem.

If you have voltage on one side and not the other, or only one pin, it is that part.

Opto couplers use a led on one side to shine onto a photocell on the other. This way, the signal gets across the isolation line but there is no conductive path for noise or faults to cross.

If you have voltage on one side, both pins, that means the LED is most likely lighting.
If you have voltage on both sides, that means the LED IS lighting and the photo receiver is working

If you have voltage on both pins on one side put none on the other, that means the LED is burned out or the photocell has failed.

 

I was trying to look at the board when OP said 115VAC goes to one pin of those, which is like ..never.
Opto's can't take that voltage..well except for galvanic isolation.

 

Its the common wire that hooks to one of the IC leads, opposed to the hot wire. Reading from hot to the IC leads I get 122, 122, 122, 122, and on the other side(near edge of PCB) I get 118, 118, 116, 122vac.

Reading from gnd to the IC leads I get 0, 0.3, 0.3, 0 and the other side 7.5, 4.7, 7.0, 0.0vac

 

It may be an AC input OPTO. Galvanic,like you said riffa:
http://www.vishay.com/docs/83675/sfh620.pdf

Paul, Are your readings 0, 0.3, 0.3, 0 from top left, top right, bottom right, bottom left?

Or like this?

 

left side first IC
122
122
left side 2nd IC
122
122
right side(near edge of PCB)
118
118
116
122

 

That is reading from hot, we dont want that, Black meter wire on ground. Red on the IC pins.

I believe thats what you did with the 0, .3, .3, 0 readings. Also, check from pin to pin on the IC.

Black probe on the bottom right, measure the top right with red probe.
then
Black on bottom left and measure top left with red probe.

That should give us enough info for now.

 

OP's measurements are wrong

 

OP's measurements are wrong

You sound like audioguru. How about some assistance to getting the right ones?

Are you saying his technique is wrong, or something different?

 

His tech is wrong giving him wrong results. The OPTO's does not use common ground.
And without a shema or seeing the board I donno where to look at.
He did not show me, thus the quote. measurements are wrong. Me no Guru. Me king as some might say.

 

top IC
Right 1.8
Left 0.1
bottom IC
Right 7.0
Left 0.0

 

I agree that we will not have exact voltages, but If the opto has power on 1 side ,the photorsensor is not receiving, then the opto is bad.
they are pretty inexpensive, so I would replace them.

 

please suggest a p/n to use.