Problem with Gateway 900G

[Mad Capper]

Re: Problem with Gateway 900G

Ok so maybe forget what I just posted.

I was working with it face down and pulled it slightly over the edge of the desk to look at the screen. I could see the whole screen light up in time with the clicking, no surprise there. For the heck of it I put it back in the back half of the housing, not even putting on the other half of the PSU/logic board cage.

When I plugged it in and turned it on it worked! I am gobsmacked. I have no idea why it was not working face down and can't imagine that there was some short or something prohibiting it from turning on.

Regardless it would seem to be fixed. I hesitate to leave it on for an extended time as I fear the original burning up of the MOSFETs was due to degrading capacitors. Thus would the safe bet, taking into account its age, the history with these monitors and the failed MOSFETs, be to do a recap to give it the best change of prolonged survival?

For the recap there seems to be some who stick to the specs on the original caps and those the up the uf or v slightly, which is the best way to go?

Again I really appreciate everyone's patience and willingness to help.

[selldoor]

Re: Problem with Gateway 900G

That's great- switching on and off a few times will be the real test

I think most would go for replacing like with like as changing can put pressure on other components - 47uf to 220uf is much too great a change and possibly so is 100uf 50v.

It should certainly improve the life expectancy of the board if you replace all except the BIG cap with panasonic FC or FM caps.

Well Done!

P.S. I was referring to post 68 in the link

[Mad Capper]

Re: Problem with Gateway 900G

I hate when I speak too soon. I ordered and installed all new capacitors. It still has the same problem it did even before I put in the new capacitors. It does the clicking and I think I have read about this particular problem.

I have steady 5v and 12v. It only happens when everything is plugged in, i.e. video cable, to logic board and CCFLs in. So only when there is a draw on the circuit. I have changed out the 47uf 25v with 100uf 25v and other options. Still nothing.

So poking and prodding and it seems to be a short on the board someplace. Attached is a photo of the approximate area of the short. What I did was take a toothpick and press in different areas. About anywhere in the area enclosed with the red line where I press the clicking stops and the CCFLs light up and there is a picture on the screen. It seems as thought the board needs to be flexed downward to make some connection and then it works.

I have looked over the board with a 10x loupe looking for cold solder joints or something that would indicate a problem. I have reheated a bunch of solder joints hoping it was a simple cold solder joint and that has not worked, or I did not get to the right one. It only seems as there is the top and bottom to the board and not a multiple layer board so I don't know where a run would be broken. I also checked continuity between many point and did not find any problems but obviously did not do them all.

So the question is what could be causing this short that pressing on it and flexing the board fixes it? How do I find where the problem is? Or should I just put a wedge in between the board and case, thus giving the board the correct amount of flexing for it to work and put everything back together and call it done?

Thanks again on this one, it would be nice to finally win one of these battles.

[Mad Capper]

Re: Problem with Gateway 900G

Still not sure where the short or intermittent contact is. I did a lot of point to point to check for continuity and everything seemed to be ok. I also reflowed many of the joints. That seemed to help but when I screwed it down it still did not work. So I reflowed more points and put some of those red paper washers you get with a PC motherboard to shim everything so there was to flex or torque on the board and it seems to be working continuously. I put it all back together and still works so only time will tell, but I think we got it fixed.

Thanks again to all for your help, I couldn't have done it with out you.