SONY FWD-50PX2 Plasma Clicking sound and red light

[soho727]

When I plug in the TV, the green light comes on and it clicks five or six times and then the green light turns red. The screen stays black and Remote and controls the TV does not work. I opened up the back cover and all capacitors look good. Please help thanks.

[tom66]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

Can you take a picture of the inside of your TV? Then the Y and Z sustain boards can be located. These are common failures.

[soho727]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

Thanks Tom66.
I've posted some pictures of TV.
Should I replace PSU or Main board?

[tom66]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

Looks like an LG chassis.

Looking from back: Lefthand board is Y-sustain, righthand is Z-sustain.

Unplug power to Y-sustain (with TV off.) Then plug TV in. Do you still get 5/6 blinks? (You won't get a picture.)

Next plug power into Y-sustain and repeat with Z-sustain. With the Z-sustain removed you'll get a dim and slow picture if the Y-sustain is functioning fine.

This will locate if any of the sustains are causing the fault.

BTW, very well engineered Sony PSU there - full of top quality Rubycon/Nichicon caps. It's nice to see something was well made once. :/

[soho727]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

Yes, inside all boards are from LG.
I disconnected the power of Y-SUS board and same...5times click and red light.
There is only one small connector from Z-SUS board which connected to control board. I disconnected it and no difference.
I am uploading some service manuals for this TV (PDF) which I got from web searching for reference.

[tom66]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

Can you post a picture of your Z-sus? It looks similar to the Y-sus, but is usually smaller and less complex.

[soho727]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

The Z-SUS board was under the Main board.

[tom66]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

Try removing the smaller white connector, on the right of that picture.

[soho727]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

I disconnect the connector which was connected to Y-SUS board (bigger connector shown at the right side of the pic) and no difference (clicks and red light).
This time, I found that when it clicks, there is small noise coming from Y-SUS board.

[tom66]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

I disconnect the connector which was connected to Y-SUS board (bigger connector shown at the right side of the pic) and no difference (clicks and red light).
This time, I found that when it clicks, there is small noise coming from Y-SUS board.

Do you have a digital multimeter?

[soho727]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

Yes, I have it

[tom66]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

Yes, I have it

Set meter to 200 V DC range. Check the Vs test point on PSU with and without Z/Y boards connected.

[soho727]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

tom66...thanks for helping me.

I disconnected Y and Z board and plug in the power.

It clicks as before and then red light. The voltage is around 240V when it clicks and 2.8V after that.

[tom66]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

tom66...thanks for helping me.

I disconnected Y and Z board and plug in the power.

It clicks as before and then red light. The voltage is around 240V when it clicks and 2.8V after that.

240V?! That's WAY too high. It should be around 170 - 200V. This might be your problem.

Can you try with just the Z sus connected?

[soho727]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

I know the voltage is too high.

Today, I measured the voltage again with Y-SUS and Z-SUS boards were disconnected.

When it clicks, the voltage keep increasing to 260V at this time and then drop to 3V.

[retiredcaps]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

When it clicks, the voltage keep increasing to 260V at this time and then drop to 3V.

One retiredcaps' bonus point for showing a picture of your multimeter. Meterman makes good stuff.

I suggest retesting your voltages with a fresh battery in your multimeter. As you can clearly see, the low battery indicator led is present and you could be getting incorrect or inaccurate readings when the battery is low.

[soho727]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

Thanks for the tip.
Changed the battery and measured again...little bit lower voltage (237V)
Still too high?

[retiredcaps]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

little bit lower voltage (237V)
Still too high?

I'm not an expert in the plasma area so I'll let others comment, but I think the voltage has to be very close to what is posted on the panel sticker.

[tom66]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

Thanks for the tip.
Changed the battery and measured again...little bit lower voltage (237V)
Still too high?

Yes, it is much too high. The voltage needs to be within 0.5V either way of the panel sticker. (There will be a sticker on the plasma panel listing the voltages, Vs, Va and usually three or four others.) What does the panel sticker say? A high voltage could be causing part of the Y board to "arc" over, hopefully it has not been damaged.

I just noticed your meter is reporting "low battery", which can cause readings to appear higher than they should. Let's do a sanity check. Take a known good (preferably new out of the packet) AA battery and test it with your meter. You should get 1.6V or less. Do you?

[soho727]

Re: SONY FWD-50PX2 Plasma Clicking sound and red light

The panel sticker shows Vs is 192V and Va is 60V.

I have no idea what the numbers of next line means.

I measured the Va voltage and it is 75V.

Then the PSU is problem?

Thanks