Vizio p50hdm dim screen

[freakaftr8]

Re: Vizio p50hdm dim screen

It would appear low to me as well. As many plasmas I have touched 115v makes no sense.

And the guide shows 115 as the set voltage for +VSC

[freakaftr8]

Re: Vizio p50hdm dim screen

I'm really starting to think I received a bad module. I would just pull it and replace it but its such a pain to do.

[freakaftr8]

Re: Vizio p50hdm dim screen

Thinking just found my issue. On the sus up pin for the sus out ipm. It's not making connection to the board. Either the resistor inline loosened up or the trace is broken. Have to partially remove the ipm to inspect further but I'm not getting a connectin with my dvm reading.. Wish me luck

[tom66]

Re: Vizio p50hdm dim screen

That could easily cause your problem.

[freakaftr8]

Re: Vizio p50hdm dim screen

Fixed!! Yep that was it. Weak solder job on the 18v pin input on sus ipm. Hey thanks alot Tom for your help and the diagram. I really appreciate it! Now if only I can get the screen wash to take care if the letterbox format someone obviously watched its whole life. Hmmmm nice when there darker in the middle. Oh well.

On another note I dialed down the -vy to 184v instead of factory 200 and adjusted ramp up and down to alleviate some red sparkles.

[freakaftr8]

Re: Vizio p50hdm dim screen

It's obvious now that the screen was lighting up somewhat from the power the zsus was putting into energizing the cells. The vscan was there to energize the buffers so hence I had a picture that was uniform. There just was no positive voltage driving the screen hense the sustain voltage which was the factor. The ipm's on the ysus were not charged due to the loss of the 18v signal. The reason they sounded like they were powered and got lightly warm is cause the backfeed from the zsus modules feeding into the ysus modules through the panel. So rule of thumb for anyone replacing ysus modules. Check your 18v line

[tom66]

Re: Vizio p50hdm dim screen

A plasma display works by using AC voltage to make the pixels sustain (emit light.) If you only have one polarity on the common side (Z-sustain) you'll get insufficient light emission. If you are missing Vzbias you will get a cloudy or purple tint to the image. There's nothing about "lack of power" about the dim image, it's just the panel's not being driven right. The reason you don't see a similar effect with a bad Y-sus is the panel can't prime and load an image in without the Y-sus.

[freakaftr8]

Re: Vizio p50hdm dim screen

Well said.