Signals from control board to PSU on a plasma

[Ashroyer05]

Can a control board or main board send 15V or so to the psu. Or does one of them send a small voltage? On a regulator I am working with pin 1 is input. If I trace it to a connector pin it goes back to a connector from one of the other boards (not the psu). The input voltage for that regulator is 15-40V according to the sheet. I'm trying to figure out why There is not voltage on the regulator or the one next to it. I need to know where the voltage comes from for Vin.
thanks for any help.

[tom66]

Re: Signals from control board to PSU on a plasma

Generally the signals from control board are on the order of 3 to 5V.

Input voltage like that is probably related to a power supply voltage like 15V or 24V.

[Alastair E]

Re: Signals from control board to PSU on a plasma

PSU will often receive a Vs-on and Va-on signal as well as sometimes, a PS-on signal from the control-board.
Still others will have a 3.3v-on and 12v-on too....

Some make sets however the control-board, will 'ground' these pins to bring the PSU active....

Different makes, different ideas, advice is--Look for a Change of State of these control-lines when activating the stby/on switch....

In Stby--often there's Only a 5V or a single supply of some voltage or other, going to the mainboard, and all other supplies are off--Until the mainboard (Or control board) Tells the PSU to fire up.....

[Ashroyer05]

Re: Signals from control board to PSU on a plasma

Thanks guys. This board is different. It has constant 3.3 V and weird voltages other places. 6 Volts appears when I fire it up but I think those voltages are supposed to be higher because they start high for a split second and then drop to 6. I traced the input voltage pins from the regulators all the way to where the control boards connect. If the pin requires 15-14 V to run and the pins go to the control boards does that only state the obvious or am I missing something big? Maybe I have a massive short somewhere?

[Alastair E]

Re: Signals from control board to PSU on a plasma

Well---

Be a GREAT idea.....

To TELL us, and SHOW us with a Picture--Just WHAT set it is!!!

[Ashroyer05]

Re: Signals from control board to PSU on a plasma

I have a few posts on this tv. I figured most would see them since i'm popping them up left and right. This link probably gives the most info in one of my comments towards the bottom: https://www.badcaps.net/forum/showthread.php?t=35401

[Alastair E]

Re: Signals from control board to PSU on a plasma

Hmm--Still doesnt give the Model-Number Or the Make/Model of Plasma Panel used in your 'Hitachi' set!
It would appear you are going about this the wrong way--I suspect a Ysus/Xsus fault and the Mainboard is shutting the set down--and Not a PSU fault....

It would also be a good idea to have just One Thread dedicated to your set/make/model/fault--
Just posting randomly about different parts on different threads just confuses others and clutters the forum up, with little info passed either way!

[tw2005]

Re: Signals from control board to PSU on a plasma

The model is in that post.

I suspect

Tv = CMP4121HDU-511,

PSU = HA00991 (1C81531)

PDP = FPF42C128128UB-51

Not sure how accurate the manuals are, might give you some idea.

SJ search showing other boards.

http://www.shopjimmy.com/catalogsear...CMP4121HDU-511

[Ashroyer05]

Re: Signals from control board to PSU on a plasma

Thank you for clarifying tw. Almost felt shot down for trying to be descriptive. I appreciate the links too i have been searching for months. As far as sustain board i ptlugged them in one at a time and no luck.

[Ashroyer05]

Re: Signals from control board to PSU on a plasma

Is it a bad idea to force the inputs high on the regulators to see if they produce an output?

[Alastair E]

Re: Signals from control board to PSU on a plasma

Have you tried running the PSU without the set, by taking the control-pins high/low as needed to fire it up?

That's what I do with dodgy PSUs.....

That would confirm whether the PSU --or the set--is faulty...
I still think that there's a fault Outside the PSU causing this--disconnecting the Vs/Va from Z-SUS/Y-SUS supplies wont always prove anything, as the set will shut down with these disconnected anyway!

[Ashroyer05]

Re: Signals from control board to PSU on a plasma

Alastair, I'm not ruling your philosophy out at all. Just have a gut feeling it's the psu. I had some shaky readings from some pins. One pin hits 19,12 V for a split second and then sits at about 6V. And I believe that is an input pin for one of the regulators, but it's coming from the control boards. I would LOVE to force the psu on but there are NO indications of what pin is what that's why I have been tracing pins but the voltages I have confirmed are confusing me.

[Ashroyer05]

Re: Signals from control board to PSU on a plasma

I DO remember at one point not having one of the ribbon cables attached from the psu to the logic board but the logic board was still connected to psu via a wire connector. At that point the Green LED on the tv would come on and stay on. The screen still was not powering on but the led stayed lit. Now the tv would not turn off at that point but I suspect that's because the logic board did not have full control because of the ribbon cables being disconnected. Is this maybe a sign that it is NOT a fault in the power supply?