Pelco 42 inch Monitor Shuts off .5 secs

[neverexisted]

Hey guys hoping you can tell me where to start with this thing. I got a seemingly brand new pelco monitor 42 inch model PMCL542F.

I visually checked the boards and all caps etc look fine no burnt spots or bulging that I can tell I've yet to do anything further because honestly I'm not sure where to start.

The monitor/tv turns on for half a second shows logo and then turns off. It also makes what I could only describe as crickets/clicking noise when plugging it in after being unplugged for awhile.

Also not sure if that is a inverted board on the far left or not.

I am just hoping someone can tell me where to start. I.e. inverter, PSU, mainboard etc.

I am attaching a video and some pictures below.

https://www.youtube.com/watch?v=RIlixvsiKB4

you can hear the crickets when I plug it in in the video.

http://imgur.com/a/WC9lx

there is a link to the hi res images


Thanks guys hope you can help

Got this from a local recycler hoping to bring it to life and make it my computer monitor.

Cheers guys appreciate your time!

[budm]

Re: Pelco 42 inch Monitor Shuts off .5 secs

Remove the two connectors for the Inverter board (the long board under the metal shield) and see if the clicking goes away.

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

Unplugged and still same noise. Upon further inspection its definitely coming out of the main PSU. I can't be sure but putting me ear as close as I can without fear of getting bitten, it seems like its coming from those blue blocks. I guess they are "AC film capacitors"?

Circled them here: http://s30.postimg.org/k45z8zd69/dnj7_Sz_Y.jpg
Also circled the entire area where I know the noise is coming from.

here is pics of the two of those blue capacitors: http://imgur.com/a/xghHz


So am I wrong to assume that they stopped using CCFL backlights in these newer model displays? If that is indeed an inverted board.

[budm]

Re: Pelco 42 inch Monitor Shuts off .5 secs

Those are X/Y safety caps Line noise filters.
Did you do any DCV checking to see if the DCV on the cold side connectors have steady DCs?

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

I did not and I only slightly understand what your talking about. But I do know how to read fairly well......

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

You mean check the dc line out on the psu with a meter? By cold side do you mean the DC side of the PSU?

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

Those are X/Y safety caps Line noise filters.
Did you do any DCV checking to see if the DCV on the cold side connectors have steady DCs?

So those basically clean the AC current before it gets converted by the transformers?

[budm]

Re: Pelco 42 inch Monitor Shuts off .5 secs

There are three white connectors on the cold side of the power supply board, those wires for the connectors go the inverter board, the main board.
The pins of the connectors are also labeled to tell you what they are.

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

There are three white connectors on the cold side of the power supply board, those wires for the connectors go the inverter board, the main board.
The pins of the connectors are also labeled to tell you what they are.

Ok gonna check voltage on them now

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

Showing 13.98v on the 12v pins, 4.98v on 5v standby. The inverter board doesn't show anything but this is with it powered off. Not sure if I should turn it on and try.

[budm]

Re: Pelco 42 inch Monitor Shuts off .5 secs

The switched 24V for running the inverter board will not be present until the power switch is activated and the monitor is fed with signal otherwise the monitor will go into standby by due to lack of video signal from PC.

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

So where should I go from here. Its a 2500$ monitor. think I should swap the inverter.

What I mean by that is itd be worth it to swap some boards if i need to.

[budm]

Re: Pelco 42 inch Monitor Shuts off .5 secs

So you have the cable between the power supply and the inverter board connected back in place but and there is no 24V from the power supply board to feed the inverter board?
And without the Inverter cable connected you also do not have 24V at the power supply connector? If that is the case then you have power supply board problem. Inverter needs that 24VDC from the power supply.

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

Should I test that with it powered off

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

So leave it in standby and test for 24v on that pin?

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

ok tested in standby and 28 volts on all pins leading to inverted board.

[budm]

Re: Pelco 42 inch Monitor Shuts off .5 secs

So all the Voltages so far are steady then?
You have indicated that it shutdown in half second do the power LED goes off or you see the image on the screen for half second and then the backlights shuts off but the power LED is still on, is that right. Or it is like as if someone turn off the power switch.
I am trying to understand the shut off part.

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

Voltage is all steady far as I can tell.

Turns on half a second shows a clear image. Standby light goes from red to green. Green light stays on after it shuts off as if it were still powered on. No image when shinning a flashlight so I Dont think that it is a bad backlight.

[budm]

Re: Pelco 42 inch Monitor Shuts off .5 secs

Voltage is all steady far as I can tell.

Turns on half a second shows a clear image. Standby light goes from red to green. Green light stays on after it shuts off as if it were still powered on. No image when shinning a flashlight so I Dont think that it is a bad backlight.

The monitor did not shutoff it is still power on with all the DCV present, only the backlights go out.
So it can be either the Inverter board or lamps problem.
Can you remove the metal shield so we can see what are on the inverter board.

[neverexisted]

Re: Pelco 42 inch Monitor Shuts off .5 secs

The monitor did not shutoff it is still power on with all the DCV present, only the backlights go out.
So it can be either the Inverter board or lamps problem.
Can you remove the metal shield so we can see what are on the inverter board.

Wait so should I power it on then check the voltages again after the monitor shuts off?