Gateway FPD1775W fades to white

[sceva]

This monitor works for 10 minutes or so, and then the screen turns white. I figure it is the main board or lcd. I found a replacement main board at shopjimmy.com for $23 and the customer is interested in repairing it. My question is: Is there a process to determine if the problem is on the main board or the lcd?

History: I have seen a few boards that 'fade to white' after being on for awhile. I had assumed that it was most likely the main board and I did not try and repair any of them. Well, the other day I was organizing the lcd panels I had taken out of scrapped monitors and found a couple to try in another monitor that had a good PS and a cracked lcd. After assembly it worked for about 10 minutes and then it went to white. My first thought was "this thing was fading to white (bad main board) and the owner got ticked off and smacked the screen" (resulting in cracked lcd - I thought this was logical). Then I looked up my notes from the replacement lcd panel and saw that the problem with the monitor it came out of was... you guessed it, it was fading to white after a few minutes. I happened to have another spare lcd panel to try and voila! It works fine. So I realized that I should not assume so much! And it made me glad that I had not ordered the main board for the Gateway!

[alexanna]

Re: Gateway FPD1775W fades to white

I also have a lot of spare monitors to play [learn with also], Before you condemn the LCD panel it might be worth a try to use a different ribbon cable,Maby the different cable will have a slightly tighter fit.
Al.

[sceva]

Re: Gateway FPD1775W fades to white

You may be onto something. I didn't have another ribbon cable, but I was able to swap it end for end and the display looked different. But I did not have time to fully see what happened, as I think the shield on the ribbon cable caused me another problem while I was trying it. The ribbon cable was laying across the bottom side of the PS board and it must have done something. I didn't see any smoke or hear any noise, but the PS is unstable now and it will not turn on.

When the PS is not connected to the main board the 5V looks good, and the 12V fluctuates between 10.5V and 11.5V. When I connect the main board, the 5V goes from almost 0V to 4V, and repeats. The power led light flashes on and off. The 12V fluctuates between 14V and 16V. I haven't dropped any parts yet, but the transformer rings ok, and the 12V and 5V schottky's seem ok.

I have another PS that has the same connector to the main board, but different inverter (this one has 2 pairs of connectors while the original has only 1 lamp at the top and bottom). I tried comparing voltages on the two, but I don't know how to check much on the PS side of things.

Attached are pics, and also a picture of the screen before I messed it up. It has white horizontal lines running thru the screen, and gets worse toward the right side of the screen. If I move this dialog box to the left side of the screen it looks good.

The ribbon was laying across the left hand side of the board, over the PS stuff, not the inverter. Any ideas on what I might have damaged or what to look for? Thanks.

[sceva]

Re: Gateway FPD1775W fades to white

I got the power supply working again.

I am still not sure if it is the main board or lcd, but I saw a main board on shopjimmy.com and by the time the customer got back to me and I tried to order it was gone. Does anyone have a PWB-0987-04 laying around?

[alexanna]

Re: Gateway FPD1775W fades to white

I am seeing a few more gateways' come in I'll keep my eye open for a video board.
Hay man how about that Missouri football team?
Al.

[switch998]

Re: Gateway FPD1775W fades to white

Try plugging it into another video board. It doesn't have to be the same model or size or resolution, they all use LVDS or TMDS so it doesn't make a difference except for parts of the screen being blank or cut off. If the screen still goes white, then the panel is bad.