screen flashes red blue green white and grey

I had the same problem as yours, and the problem is not caused by the bad logic board or bad solder on the Graphic chip. The alternating color is indicative that the display is not getting signal data from the logic board. What happened here is that the data connector that goes directly to the LCD display has become lose or became disconnected completely. There is another smaller connector near the hinge. That is the CCFL (lamp for the display). The fact that you are seeing screen color and levels of grey indicate that this function is not the problem either). The solution is fairly simple.

1, Remove the four screws on the side of the display.
2. Using a thin blade, slide on the side of the display bezel to pop off the cover with the Apple logo.
3. Take a picture of the back of the display without the outside cover on so yiou can see the placement of various Kapton tape.
4. If you can carefully remove the metallic tape about 2/3rd of the way up, yoou'll see that there is a flat ribbon cable connector that plugs into the mating part in the display. In mine this connector was no longer connected. Try plugging it back in and see if the display now worked correctly. If it does, do the next step to secure it better.
5. Remove obne screw near the hinge that secures a metal mesh ground strap.
6. Remove several screws on the side holding the shielding.
7. Carefully remove the shielding. Just near the display connector above, attach a clear tape to keep the data connector from coming off again.
8. If the connector is intact, check the length of the this cable to see if there is a pinch damage near the hinge. That is probably the second reason you get the flashing full color screen.
9. Re-assemble everything, and you're back in business.


Note: graphic display chip problem shows a different symptom, usually scrambled video.

Hey mamahoney and Welcome to Apple Discussions,

the apple image flashed for maybe a half-second, and then the screen turned black, then began to flash white, red, blue, green, and grey. Sometimes it looks like it is trying to show some desktop image, but only for a split second, then it goes back to flashing the different colors.

Well that sounds like the classical graphics chip ball grid array problem. A positive diagnosis would be to boot it with pressure on the GPU usually from underneath on the bottom of the logic board in area of the the option-Apple key.
If you pull the lower case off you'll see an open area on the underside of the logic board (you'd have to remove the lower shield to do that ) under those keys. You can apply pressure there without removing that shield and boot it. If the problem goes away or is better that would confirm the diagnosis.
If that is the case Apple will ask $300+ to repair it.
If you feel comfortable removing the logic board it would cost you $79 plus shipping one way for a reball. There is a finite possibility that the procedure could kill your GPU.
Richard

PS: If you don't decide to repair it please don't shoot your old horse. I repair these and donate them to teachers in the inner city here in Chicago.

Message was edited by: spudnuty

Hey magmahoney,

I had this problem with my iBook last year. I sent it in to Apple and they said that it was a logic board problem and that I should send it in. I did, and $300 later, I got it back and it worked fine. They replaced everything except the hard drive on it for that flat rate.

I had the same problem with my iBook G4 1.2mhz. It had been working perfectly for years and then suddenly the screen started to go black and then cycle through the colors. It seems that it's a flaw in the manufacture/design of this computer that many iBook G4's develop sooner or later. The computer is long out of warranty and it was either fix it myself, spend hundreds fixing a machine worth half of that or use it for a large paperweight.

This article describes the problem and one possible solution. http://www.coreyarnold.org/ibook/

Again, do it at your own risk and only if the symptoms fit your computer. If it doesn't work or it's botched your computer may be done, but if you have this problem it's pretty much done anyway.

I did not do the shim-job. But clamping the computer or torquing the body would get it to work, temporarily. It was a classic cracked/bad contact problem. Shim it, solder it or send it off for someone else to repair.

Instead of the shim solution, after the chip was identified, I got the SMALLEST soldering iron I could easily find (a 15 watt plug in model for about $9 at Radio Shack with a sharp point on it) and proceeded to heat up the pins on the chip to melt the solder and reestablish contact. I had to use a magnifying glass to do it and it was VERY precise work. I got the soldering iron hot and tinned the tip wiping off any excess solder. Too much solder or any additional solder and you'll bridge pins. I then just touched and drew the tip of the iron away from the body of the chip and toward myself. The first time I tried it, the computer worked pretty well for a couple of hours (a significant improvement), but then went back into the black and then solid color cycling screen. I thought maybe I hadn't given it enough heat and time and redid the process. Maybe a second or two on each pin, no more. Certainly no additional solder or it'll bridge the pins and short out and your computer will be even more permanently done than before. Using the magnifying glass I could see that the solder around the pin would change color. That's enough. Then draw the iron off the pin at right angles to the body of the chip. Then on to the next pin.

The second try was successful and I've had the computer on for hours with no crashes now, when before the fix it wouldn't run 3 minutes.

Disclaimer: do this at your own risk. You can use the shim system outlined above, but I believe that will only last temporarily and distorts the board causing more problems. I didn't dismantle the board but only removed the bottom and heat shield. So far so good. What do you have to lose with a machine that's not working that would cost you big bucks to repair otherwise?

My son in law had a 12" iBook G4 with similar problems. I did the same thing to his computer and it's now working well too. Thus far, two for two.

Hey Red..,
That chip you're soldering on the bottom is U28 correct. That's a dual voltage regulator and causes a non start problem as in the Corey Arnold site.

then went back into the black and then solid color cycling screen

That's caused either by a GPU chip going bad or the BGA coming loose.
I believe this is caused by the display hinges getting stiff and causing undue flexing of the chassis and thence the logic board. It can also cause failures of the display frame or the rivets holding the hinge assembly to the upper frame.
I remedy this by rebuilding the hinges.
Richard

i had the same problem there is a simple solution if you have any lego at home find a thin 2 block piece, cut of the ends, cut out the middle bump (on the bottom)and cut out a small square of latex from a glove and put it on the chip then cup the lego piece over it and cover that with the dc in cable i found that it cups perfectly over the chip and holds down the pins. the only problem is that the laptop will sit unevenly on a table. but mine has been working for about a week now. tell me if u didnt quit understand my instructions

Thanks so much cmdrdatatx your fix worked for me.I was able to fix the 'white red green blue white grey'on a coleagues G4.

Here is my revised version of your list

This is fiddly but do-able.
Be very careful not to electrocute yourself. If in doubt don't start this!
You will need a hex key to fit the bolts holding the screen edge on, and a tiny cross head screw driver to loosen the shield.

1. Remove the four screws on the side of the display (hex driver or allen key).
2. Slide off the side of the display bezel to pop off the cover with the Apple logo.
don’t use a knife – do this with your fingers – it’s lose enough!
3. Take a picture of the back of the display without the outside cover on so yiou can see the placement of various Kapton tape.
4. Carefully remove the metallic tape and the yellow tape from the edges.
5. Slack off 4 screws on the side holding the shielding. (you don’’t need to remove them)
6. Carefully remove the shielding. This is thin and easy to crease.
7. About 2/3rd of the way up, you'll see that there is a flat ribbon cable connector that plugs into the mating part in the display. (The uni-directional bonding strip has probably dried out and the cable is no longer stuck to the surface.)
8. In mine this connector was no longer connected. Try plugging it back in and see if the display now worked correctly. If it does, do the next step to secure it better.
9. Put a new piece of uni-directional bonding strip just bellow the connector to take the strain.
10. Re-assemble everything, and you're back in business. The shield is fiddly to get back on, and flimsy and easy to bend, be careful!
Uni-directional bonding strip = Selotape!

Thanks

Jim

Thanks for posting this solution. I was having this issue and my local apple tech said the logic board would probably need to be replaced. I tried your solution and now my G4 works perfectly.