JVC 56P575 no power

[andy]

...

[rca2000]

Sorry--I have been busy for the last few days--with the 127 corridor sale and such.

ANYWAY...before you order ANY parts... what did you measure on the STR IC--to hot ground ? :Pins 1, 4 and 5...in particular. If 4 or 5 is off by much...that optocoupler is likiely loading things down.

[pac.attack76]

Thanks Andy for the service manual. Very handy. I'm having trouble fiuring out which pins are which and if the board needs to be installed in the set when i test. Where is "hot ground"?

[rca2000]

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.

[andy]

...

[pac.attack76]

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.

[pac.attack76]

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

[rca2000]

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.