Hot ground is ther negative lead of that big capacitor you measured 171 volts on. This is the reference point for ALL voltages on that IC.

Looking at the IC from the front...see where the pins all go into it. From left to tight--pin 1 should be on the left and in order from there. I KNOW they are "staggered" in the way they end up on the PC board..But if you look at how they enter the IC--you should be able to figure out which pin is which.


I tried to dowlaod that manual myself...but was NOT able to do so for some reason.

...

Ok, guys, looking at the board where the words "live" and "isolated" read upright, the pins are like this:

. .
. . . With the cap out to the left. Now, going from left to right, left to right, i got: -.033, -14.06, -.003, -1.26, .000

Not sure if i did this right. Red on right side of cap since the other side has a plus mark. Set to VDC.

Did i do this right. If not, i can hit it again.

You did it BACKWARDS. Put the black probe lea don the hot ground. Use ther red or positive one---for all of the other readings.

BUT...i did NOT see any 171 volts on ANY pins of that chip. Are you SURE_-you got all of the pins? 2 of them are scattered from the otherrs--remember. if you did NOT...then check those 2 large resistoirs beside of that chip...and see if they are OPEN. They likely read LESS than one ohm. If OPEN--that ahip IS shorted.

Ok, i figured as much. I'll hit it again tonight or no later than tomorrow. I'll need to get this part, whatever it ends up being, ordered so i can get it in soon.

Yeah, i missed two pins. Layout is actually:

. . .
. . .
.

Now from left to right with black on cap neg. i get:
169.8, 13.73, .017,
.000, 1.309, .004,
.000
Note these are taken with board out of set but still plugged to ac.

At this point...I would re-check ALL diodes and any transistors near that IC..on th HOT side of it (within that white drawn area surrounding HALF of the transformer and optocoupler.) be SURE to check any diodes and make sure none are shorted.


If you do NOT find anthing...that i would order than IC and the optocoupler--as a "just in case". Your voltages indicate the IC is NOT shorted and is getting full voltage from the big cap and it ALSO looks to be geting its "start voltage" too. I would gues it is just bad.

I have a guy in the area that looked at the board the other day and he thinks the optocoupler is bad. Probably $1 or $2. Hes wondering what the readings should be if it were good. Getting voltages on the large cap and STK.

If the optocoupler is good, what should the reading be?

I'm sure you did this but the picture of the PC side shows a solder connection blown loose with the number 912 going to it. Did you check the resistor and resolder that connection? Just curious.

C912 is likely some sort of "snubber cap" for the primary of the SMT transformer.. Somehow I missed seeing that. R912 is on the supply line to the chip...if it was open...you would NOT see 171 volts on the chip...but check the connections anyway..

And YES...IF that cap is not connected...the PS may NOT run at ALL.

Not sure EXACTLY what the voltage on the hot-side of the opto should be.... withoust seing a manual...BUT it WILL NOT be high...likely 12 volts or LESS...on BOTH pins..

checked both c912 and r912. both connected well. not sure how to test them. i'm assuming the board would need to be powered but not sure what meter setting to use. still trying to get used to this whole meter thing. the solder on r912 just has two different appearances. shiny and dull surface, im guessing made it look like it had lifted. any ideas?

rca2000, i have the pdf service manual if you want me to email it to you.

I guess i'll just order the chip and optcoupler. Chip is $16 shipped. How do i look up the optocoupler? I'm 3 days away from ordering so i just have to figure out what to do. If this doesnt fix the no power issue, then i dont know.

Well, off to the storage building she goes. Not sure what i need still so i didn't order anything. Probably sit in storage till i finally decide to toss it.