Sony FWD50Px2 power supply voltage

[fleetwise]

Just opened up my very first Plasma display, a Sony FWD50PX2 and have a few questions about the power supply. When I plug the set in, the red LED on the front lights so I have standby power. Pressing the power button does nothing.
I jumper the 5Vst to the rly pin, (with board in place and all connectors plugged in) the relay clicks and the PSU comes on but there is NO voltage on the Va, Vs or 3.3Vst output pins. All other pins show normal voltage as per the label.

After playing with the PSU a little more I found that the 3.3Vst will come up if I ground the off-on pin AT the voltage regulator that feeds that output pin(it has 4.89 volts to it, which turns it off). I have not tried to force the Vs or Va on.

All Sonys triage manual says is to check ACD and 5Vst for power and to replace the A board if the AC detect and 5 volt standby is normal. If that doesn't fix it then replace the PSU. I don't want to replace either if I can help it.

Should the Va, Vs and 3.3Vst come on when I force the PSU on?
Does the control(A board) turn these on after the PSU comes on?
Is there a diagram of this PSU or A board anywhere?
What other brands use this PSU? (KN-PowerTek KNP-6300 Rev A)
Have I asked enough stupid questions yet?

[PlainBill]

Re: Sony FWD50Px2 power supply voltage

Just opened up my very first Plasma display, a Sony FWD50PX2 and have a few questions about the power supply. When I plug the set in, the red LED on the front lights so I have standby power. Pressing the power button does nothing.
I jumper the 5Vst to the rly pin, (with board in place and all connectors plugged in) the relay clicks and the PSU comes on but there is NO voltage on the Va, Vs or 3.3Vst output pins. All other pins show normal voltage as per the label.

After playing with the PSU a little more I found that the 3.3Vst will come up if I ground the off-on pin AT the voltage regulator that feeds that output pin(it has 4.89 volts to it, which turns it off). I have not tried to force the Vs or Va on.

All Sonys triage manual says is to check ACD and 5Vst for power and to replace the A board if the AC detect and 5 volt standby is normal. If that doesn't fix it then replace the PSU. I don't want to replace either if I can help it.

Should the Va, Vs and 3.3Vst come on when I force the PSU on?
Does the control(A board) turn these on after the PSU comes on?
Is there a diagram of this PSU or A board anywhere?
What other brands use this PSU? (KN-PowerTek KNP-6300 Rev A)
Have I asked enough stupid questions yet?

I don't know.
Probably.
Have you tried Google?
Apparently LG Electronics supplied that panel (and power supply) to Sony?
Not really, most of them were intelligent.

PlainBill

[Village Electronics]

Re: Sony FWD50Px2 power supply voltage

Just opened up my very first Plasma display, a Sony FWD50PX2 and have a few questions about the power supply. When I plug the set in, the red LED on the front lights so I have standby power. Pressing the power button does nothing.
I jumper the 5Vst to the rly pin, (with board in place and all connectors plugged in) the relay clicks and the PSU comes on but there is NO voltage on the Va, Vs or 3.3Vst output pins. All other pins show normal voltage as per the label.

After playing with the PSU a little more I found that the 3.3Vst will come up if I ground the off-on pin AT the voltage regulator that feeds that output pin(it has 4.89 volts to it, which turns it off). I have not tried to force the Vs or Va on.

All Sonys triage manual says is to check ACD and 5Vst for power and to replace the A board if the AC detect and 5 volt standby is normal. If that doesn't fix it then replace the PSU. I don't want to replace either if I can help it.

Should the Va, Vs and 3.3Vst come on when I force the PSU on?
Does the control(A board) turn these on after the PSU comes on?
Is there a diagram of this PSU or A board anywhere?
What other brands use this PSU? (KN-PowerTek KNP-6300 Rev A)
Have I asked enough stupid questions yet?

My memory tells me that the TV is an LG. Sony had a ton of problems with the sustain boards in these. The "F" designation means this unit comes out of the broadcast group. Sony was extra kind to these customers who often paid $10 and above for the units. Until recently the boards were replaced in pairs for free. Sony published a technical bulletin to identify which boards went into which lot numbers and the serial number is a requirement to identify the right part number. Most likely any will work.

Disconnect the both boards to see if the VS and VA come alive. If it has no voltage change PS, Ysus, Xsus and your good to go.

[fleetwise]

Re: Sony FWD50Px2 power supply voltage

Thanks, I was able to find more on an LG than Sony but still not a lot.
I decided to force the whole PSU on. It sat and ran with everything on for over 5 minutes with no smoke, glowing boards or voltage dropping at any output pins on the PSU. The panel seemed to prime without any problem so the Zsus or Ysus boards may not be totally bad. Only thing I saw was the Vs voltage was at 190 and the sticker on the panel says it should be 194. The Va was at 60 volts which is what it should be.

Guess I'll have to look at that A board some more. That means I have more questions if I may ask.

If I plug a cable from my pc com port to the rs232 do I need any proprietary software or would something like the old hyper terminal in windows 98 work?

Should I have communication to the micom with the panel in standby?

[PlainBill]

Re: Sony FWD50Px2 power supply voltage

Thanks, I was able to find more on an LG than Sony but still not a lot.
I decided to force the whole PSU on. It sat and ran with everything on for over 5 minutes with no smoke, glowing boards or voltage dropping at any output pins on the PSU. The panel seemed to prime without any problem so the Zsus or Ysus boards may not be totally bad. Only thing I saw was the Vs voltage was at 190 and the sticker on the panel says it should be 194. The Va was at 60 volts which is what it should be.

Guess I'll have to look at that A board some more. That means I have more questions if I may ask.

If I plug a cable from my pc com port to the rs232 do I need any proprietary software or would something like the old hyper terminal in windows 98 work?

Should I have communication to the micom with the panel in standby?

I've never even tried that. One thing to watch out for. I was digging through the service manual of a TV recently and they made it clear you needed a RS-232 - TTL level translator (something like the MAX232) between the TV and the computer.

There is no guarantee Sony does the same, but I checked the LG Electronics schematic for a similar model and the connector is wired for RS-232 levels.

PlainBill

[fleetwise]

Re: Sony FWD50Px2 power supply voltage

It has been a couple weeks, but I can say I made a little progress on this panel. I tried the rs232 but I have no idea of the command structure even after looking at the protocol book for this model. I do know it has a max232 chip on the board and it looks like the tx and rcv are swapped so I can use a straight cable and not a null cable. In fact I tried both. It doesn't respond to the null cable but returns a strange looking "a" symbol with the straight cable.

I found that a universal remote will turn it off and on. But all I'm getting is a bright white screen and the buttons on the top of the panel do not work.

Anyone ever kick one into the full white mode to set the Va, Vs voltage?
Do the buttons work while in this mode?
Will it stay in this mode if powered off and back on?

This thing makes me feel downright ignorant. Where or what should I try next?

[fleetwise]

Re: Sony FWD50Px2 power supply voltage

Oh also the volume OSD looks fine when I run the volume up and down so it does show a picture.

I'm tempted to go knock on the door of the guy that sat it out on the street and ask if he has the remote for it.

I think he set the panel to work by the remote only and when the remote broke he was locked out and just trashed it.

[fleetwise]

Re: Sony FWD50Px2 power supply voltage

OK, here is where I'm at. Two weeks playing with a plasma panel thinking it was broken when all it needs is the correct remote.

One good thing I gained from it all was I got to play with my oscilloscope and learn dang near every circuit on the PSU, control board and every other board except the audio passthrough and amp.

Now to figure out how to unlock it so I can use the buttons on the panel, fix the color inversion and white background when it has no signal.

[rayrod81]

Re: Sony FWD50Px2 power supply voltage

I have fixed a few of these sony plasma displays and the settings that you need to change will all be in the menu. I had the FWD-42PV1 most recently. There was a setting in the menu to be able to use a remote only, display controls only, or both. Yours must be set to remote only. There is a setting to turn the picture inversion on or off and a setting to change the background color when no signal is applied. You should be able to use any Sony remote as I used a remote from my Trinitron Wega and was able to control all features on the display. You can get one online for about $10-$15. If you want to get the exact remote for that display it is an RM-980 I believe. It will cost about $30. Hope that helps.

[fleetwise]

Re: Sony FWD50Px2 power supply voltage

Just a final followup. Rayrod81 you were right. The remote fixed all the problems. I will have to put this at the top of the list of things to check when working on a Sony with similiar problems.

PlainBill as a side note, the rs232 also works now so at least on this model you don't need the jig, Max232 translator or any special equipment. Thanks all