Protron PLTV-32c won't power on

[whitemus]

I have a Protron PLTV-32c that won't power on. It has a standby light that is orange when it's first plugged in, and then turns red. I push the power button and it turns green for a few seconds, but nothing on the screen. The power supply and mainboard appear to be in good shape as far as the caps go. Any ideas on what I could check for?

[Mad_Professor]

Re: Protron PLTV-32c won't power on

I have the 26" version of this tv.

Grab a flashlight and shine it into the lcd and see if you can see an image. If you can then the problem is with the inverter and ccfl bulbs or power supplying the inverter.

If you have a DMM and if comfortable doing it, I would recommend checking the voltages coming out of PSU, it should be labelled on the board what they supply.

Also if you can, post clear focus pictures of the PSU and inverter.

[whitemus]

Re: Protron PLTV-32c won't power on

I couldn't see anything with a flash light. I tested the voltage on the power supply, the only reading I could get was the 5v reading for the standby. 24v was reading .25 and the 16v was reading .25.

[budm]

Re: Protron PLTV-32c won't power on

Bad cap can look normal but can have high ESR.
We need to find out if the power supply board is getting the PS_ON signal from the main board.
Please post good, clear, focused pictures using an attachment function so we may be able to tell you the test points we will want you to test.

[whitemus]

Re: Protron PLTV-32c won't power on

Here is the main board.

[budm]

Re: Protron PLTV-32c won't power on

Pictures of the Power supply board as a whole top and bottom, and close up of the connectors so we can see if they have any labels on them to identify the pin functions.

[whitemus]

Re: Protron PLTV-32c won't power on

Here is the Power Supply.

[budm]

Re: Protron PLTV-32c won't power on

OK, CN3 connector pin with the label 'POWER' is the Power supply on input signal sent from the Main board which will turn on the 16/24V power supply circuits, it should have more than 3VDC at that pin with ref to the chassis ground. See if it has that voltage.

[whitemus]

Re: Protron PLTV-32c won't power on

I am getting 0 on that pin. I get 5v from the two 5v pins.

[budm]

Re: Protron PLTV-32c won't power on

Well, that means the main board is not sending the signal to turn on the 16/24V power supply, without that, you will not have 24V to run the backlights (backlights inverter also need backlights on signal from the main board), or sound (16V is for sound).
There are many regulator ICs on the main board. I need to see straight shot pictures of the main board.
Can we also see the whole TV to see how all the boards are connected.

[whitemus]

Re: Protron PLTV-32c won't power on

Here are some pics of the mainboard removed from the tv. On the pic of the whole tv, there is a gray box on the right. That is the tuner board. Just let me know if you think I need to take that out and get some pics of it too. If there is any specific parts of the main board that you need to see closer, just let me know. Thanks for you help!

[selldoor]

Re: Protron PLTV-32c won't power on

Pictures are just not quite in focus - can you get them any clearer - good light
is the key. There re two brown blotches on the last picture - what is on the other side?

[whitemus]

Re: Protron PLTV-32c won't power on

The brown blotches appear to be some flux. The scraped right off when I picked at them. I'll upload some better pics in a min.

[whitemus]

Re: Protron PLTV-32c won't power on

Here is some better pics. I took them outside to get better lighting.

[selldoor]

Re: Protron PLTV-32c won't power on

Ok its flux - but what is on the other side of the board

[whitemus]

Re: Protron PLTV-32c won't power on

These circles are where the brown spots are on the back side of the board.

[selldoor]

Re: Protron PLTV-32c won't power on

Hmm - nothing there then. Picture is much better thanks - can you do the back as well

Here are the datasheets for the 3 big regulators

[Mad_Professor]

Re: Protron PLTV-32c won't power on

The brown blotches appear to be some flux. The scraped right off when I picked at them. I'll upload some better pics in a min.

Ok its flux - but what is on the other side of the board

These circles are where the brown spots are on the back side of the board.

Those are un-drilled or un-used holes on the pcb, quite common.
Also don't scrap/pick, you can easily break traces.

Focus on the task at hand, we need to find out why the signal board is not sending the PS-ON to the PSU.

[whitemus]

Re: Protron PLTV-32c won't power on

Here's a better picture of the back.

[selldoor]

Re: Protron PLTV-32c won't power on

Focus on the task at hand, we need to find out why the signal board is not sending the PS-ON to the PSU.

OK your Madness you talk him through it.