Philip 170B4 LCD

[gobbler]

Hi

I have this Philip 170B4 LCD, it powers up 1s then shutdown.
Power led is still on. I suspect the transformer is faulty using the flyback tester.
The transformer part number on it is HJC-S2258.

I know this transformer was manufactured by http://www.hjc.com.tw/company.htm

I cannot find the specifications of this transfer, anyone managed to buy a replacement before?

Thanks.

[Bobdee]

Re: Philip 170B4 LCD

Hello Gobbler
When you say it powers up for 1sec do the B/lights come on and you see signal???
When you say suspect transformer do you mean the P/Supply transformer or one of the inverter transformers???
Also when it shuts down with green Led have you tried shining a bright torch into the screen to see if you can see video signal (desktop etc)???
Bob

[gobbler]

Re: Philip 170B4 LCD

Hi Bob

Yes, the B/lights does come on, I saw the cable not connected message.
I mean the power supply transformer. I used a flyback tester, one of the primary winding is shorted. There is no 12V power to the inverter module from the power supply module.

For your last question, I did not do the test as I had desoldered the transformer out.
If got chance I will test it and revert.

[Bobdee]

Re: Philip 170B4 LCD

Hi Bob

Yes, the B/lights does come on, I saw the cable not connected message.
I mean the power supply transformer. I used a flyback tester, one of the primary winding is shorted. There is no 12V power to the inverter module from the power supply module.

For your last question, I did not do the test as I had desoldered the transformer out.
If got chance I will test it and revert.

Hello again
The green LED suggest the mainboard is getting power (but do the torch test)
Also you say B/Lights come on so 12V has to be there briefly
I am no ace on power supply problems but that says to me, that the transformer is OK
Sounds like the inverter is shutting off, Check if the Blon goes off when the screen goes off
Bob

[gobbler]

Re: Philip 170B4 LCD

Hi Bob

I did the torch test, cannot see the video signal from my desktop.
I also notice, every time I pulled out the vga connector to the lcd monitor and connect it back, the lcd display for a second and shut down.

During my desktop boot up, I can see the lcd flashed 1 second display 3 times.

So any suggestion?

[Bobdee]

Re: Philip 170B4 LCD

Hi Bob

I did the torch test, cannot see the video signal from my desktop.
I also notice, every time I pulled out the vga connector to the lcd monitor and connect it back, the lcd display for a second and shut down.

During my desktop boot up, I can see the lcd flashed 1 second display 3 times.

So any suggestion?

Hello again
Can you swap Vga cable, to eliminate faulty Vga cable???
Also after that can you try your monitor on another PC or try another Monitor on your PC to eliminate a PC graphics card problem???
Can you post pictures of the top and bottom of your P/Supply board???
There are no pictures of this board on the forum so they will help us,also post board number if you can for cross Ref purposes it helps to see if another monitor uses this P/Supply
Did you check if the BLON signal turned off when B/Lights go off???
Bob

[gobbler]

Re: Philip 170B4 LCD

Hi Bob

I tried with a new vga cable, same result. Tried another PC, same.
The inverter IC part no. is 0Z960S but I cannot find the datasheet, I cannot measure the Vcc.



<a href="http://s265.photobucket.com/albums/ii239/warlord2045/?action=view&current=P1010055.jpg" target="_blank"><img src="http://i265.photobucket.com/albums/ii239/warlord2045/P1010055.jpg" border="0" alt="power supply board"></a>

[kc8adu]

Re: Philip 170B4 LCD

sounds like a bad lamp or 1/2 of the inverter quit.got any lamps from a junker you can plug in for a test?

[gobbler]

Re: Philip 170B4 LCD

I had took out both CCFL lamps, look fine to me as no black mark.
Just found the inverter IC datasheet, measured the Vcc in, only 5.4V.
Really too low voltage to turn on inverter IC.

[Bobdee]

Re: Philip 170B4 LCD

I had took out both CCFL lamps, look fine to me as no black mark.
Just found the inverter IC datasheet, measured the Vcc in, only 5.4V.
Really too low voltage to turn on inverter IC.

As there is no video when you shine torch into screen as you did, then the CCFLs and Inverter are probably not at fault
Have you taken the output readings to the the mainboard???
This looks like P/Supply fault to me
What made you suspect the Transformer in the first place???
Bob

[gobbler]

Re: Philip 170B4 LCD

I desoldered the transformer out and tested it with a flyback tester. Found a few windings to be shorted. I hope I am correct.

[baker1640]

Re: Philip 170B4 LCD

I have the same monitor and I see that the green light stays on and only one of the inverter circuits gives the high voltage. I found a manual on line but it fails to give the inverter schematic. I don't know where to measure the blon as mentioned above. The picture is exactly like mine. I have a friend with 40 of these mostly with the same problem so obviously a common failure. I will appreciate any help and post what else I find.

[gobbler]

Re: Philip 170B4 LCD

i am hoping to find a similar set to swap cards to identify which card is giving problem.