Apple iMac G5 1.9Ghz Screen Problem and Fans not working

Apple iMac G5 Screen Problem
Apple iMac G5 Screen Problem

Last week I was at a used music shop in Nagano-city Japan where I bought a Roland Juno 106S which I posted about in a previous article below. During that time I found a used Apple iMac G5 1.9 Ghz computer for sale. The main problem though was that the screen was messed up as you can see in the photo. The sales clerk was nice enough to actually give me the iMac G5 after I bought the Roland synth. Thus I basically went home with a free Apple iMac G5. I do have problems with it though and I’ll post some details here.

First the Apple iMac PowerPC G5 is a 1.9Ghz with a 160GB HD and 512MB Ram. The serial number is W85422xxxxx and it has Mac 10.5.8 OS loaded inside. I access the computer using an apple keyboard, mouse, and an external PC VGA monitor hooked up with an apple VGA connector cable. The computer basically works pretty good when using an external monitor.

The two main problems though are one, the computer screen is pretty much shot. You can see some vertical lines on the right hand side and the left is just totally black or Gray sometimes. Another big problem is that this computer runs pretty hot. In fact, I cannot get the internal (3) fans to work at all when running in normal mode. If I reboot into single user mode the fans will run at full speed of course. I just can’t get the fans to run at all during normal operation which is likely why the computer is running hot. The logic board or something is not controlling the fans properly.

I installed a software application called “Temperature Monitor” and here are some results after one hour of basic usage. Note that I have applied the setting “Reduced” in Energy Saver Preferences. All temperatures are in Celsius…I repeat in Celcius!!

Temperature Monitor = 84.8 degrees C
Graphics Processor Ambient Air 74.8 degrees C
Graphics Processor Temperature 84.6 degrees C
Hard Disk Temperature 53.0 degrees C
Incoming Air Temperature 35.0 degrees C
Memory Controller Ambient Air 63.8 degrees C
Memory Controller Temperature 85.5 degrees C
Optical Drive Temperature 45.4 degrees C
SMART Disk Maxtor 6L60M0 (L36XGYG) 55.0 degrees C

Those temperatures to me seem to indicate the computer is running VERY hot. Unfortunately there are no software solutions to control the fans like with G4 computers so I either have to get something fixed, replaced, or find an external cooling method.

The hottest point on the computer is the upper left hand side when facing the front of the screen. That area is where the Power Supply sits if correct. That area gets extremely hot but all other areas are actually not too bad. Yet when I look inside I can’t find any obvious problems in that area.

Yesterday I spent a couple of hours taking the iMac G5 completely apart. Inside I found the Power Supply to be completely intact. The capacitors showed no signs leaking. There were no bulges at the ends of the capacitors which actually looked pretty good. In addition, I removed the logic board because I knew the G5 has been plagued with logic board failures. Again, the logic board capacitors all looked brand new with no signs of bulging or rounded ends. In fact, everything looked great inside so I’m really wondering what could be the problem. I put the computer back together a bit disappointed that I couldn’t any obvious problems.

Likely at this point the problem could be anything from the logic board, PSU, graphics boards, or screen etc. The computer runs very well for about an hour and then I feel I need to shut it down because I don’t want it to get too hot and cause a meltdown. I don’t think it’s worth it to dump any additional money into the computer as I really don’t know what’s wrong with it yet. I could refurbish the logic board and replace all the capacitors. Perhaps that might fix the fans and if lucky kick in the monitor again. I’m not sure yet.

I’m posting this article here because I’ve really done a lot of research on this over the past few days and found very few people with my symptoms. It seems most people with Apple iMac G5 have fans that are too loud, hundreds of vertical lines on the screen, or G5 computers that just shut down intermittently. I do know that the Logic Board is connected with fan usage and the screen. Whether the capacitors have something to do with this I don’t know. It’s puzzling. I WISH I had the loud, full speed fan problem that 99% of other iMac G5 users have. That would at least help my overheating problem…laugh.

For now the free iMac G5 that I got has not cost me any additional money yet. I can get a solid hours worth of special app work done if needed. I can rip the hard disk and possibly even the super drive. I also got an Apple keyboard and mouse so that’s worth something there of course. Parting it out might be the best bet, but I’ll likely just let it sit there and continue to investigate what might be the probable cause. There are a TON of people who have issues with the iMac G5 series computers. Looking at what I have here, I’m so glad I didn’t dump my money into one of these. I’d be pretty upset if these symptoms happened after shelling out lots of money. It just reminds me that despite all the glory of Apple lately, they do use crappy components in some of their products like most companies likely do as well. It’s a shame Apple customers have had to deal with all of these G5 problems. Hopefully the new Intels are much better which I have yet to purchase. I’m getting there, but these G5 issues are starting to make me wonder.

I’ll post updates as I find additional info. Stay tuned!

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5 thoughts on “Apple iMac G5 1.9Ghz Screen Problem and Fans not working

  1. Eugenia

    My computer has exactly the same problems. I bought it in 2005 so it is expected to have a problems, and it has been the only one in all these years. Did you find any solution that I can work on it too?

  2. Paul

    The screen problem is common with these machines. If you have connected an external monitor and you get a working display there is nothing wrong with you graphics boards. I recently had the same problem and managed to source a new replacement screen from a manufacturer in China for less than $100. You need to be very careful with the specs of these screens as your Imac wont boot at all if they screen does not match the original factory spec.

    Sorry cant help with your fan problem

  3. mim

    hi jim
    re: overheating as my above post. before using info from the above 3 links, i ran “disk warrior”, and my overheating has magically disappeared!

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