How reliable are new analog/video boards or flyback transformers when you replace them on tray loading iMacs?
Here's why I want to know:
I've been wanting to try this project for a while, and finally started it. I have a Grape iMac 333Mhz, and I'm attempting to replace only the motherboard, hard drive and optical drive, while keeping the original crt screen, and power supply. Following some guides to install iMac motherboards in ATX cases, I was able to make a wiring harness that will adapt the iMac's power supply connector to a 24 pin ATX power supply connector, and it worked! Initially I tried with an Intel d945gclf2d, which is a dual core atom 330, with the 945gc chipset, but it wouldn't power on all the way. Using MacTracker, I discovered the the power supply in these is only 80 watts, so I tried the new Asus at3n7a-i, which is the same cpu, but with the nvidia ion chipset, which uses much less power than the 945gc. This board fires up just fine using the iMac's original power supply! Unfortunately, I wasn't able to get anything on the iMac's screen.
Before even buying a motherboard, I had tested the iMac's screen by hooking up a hd15 to db15 adapter that had come with an old mac radeon that I bought, connected to the vga out on my Lime iMac DV. It worked the first time, but then in later tests, I noticed a lot of flickering, and large black areas. I thought (hoped) that it was just the db15 extension cable I was using, but now the iMac will not display any video at all. I even tried putting it back together with it's original motherboard. I'm almost certain it's the flyback transformer from reading all kinds of information online, but I don't know if it's worth fixing for a couple of reasons. I suspect that even though I could get video from the vga out on the iMac DV, I still won't be able to get it from the itx board or any other vga output except one from an iMac G3. I suspect this because I could still get output from the iMac DV, even after I got no video from the itx board (I know the itx board works because I connected it to another screen). My other concern is that if I fix it, and I AM able to get the vga out on the itx board to drive the iMac's screen, that it will somehow over stress the flyback transformer and cause it to fail again soon after the repair.
Anyway, I was really excited and somewhat surprised that my wiring harness actually worked to power on the itx motherboard, but it was frustrating when the flyback transformer went out. Maybe something I did caused it. Probably.
I may end up trying this on a slot loading model in the end. If I fabricate a frame that mounts the motherboard under the optical drive (it will fit), and the hard drive in the back, I think it will work. They also have more power (150w) and more reliable flyback transformers. The wiring will be a nightmare, but I think I can handle it. The pinouts are well documented.
If anyone can advise me on whether it should be possible to drive the crt with the itx board, and on the flyback transformer repair, I would really appreciate it. I found an article on how to do it, including precautions regarding discharging the crt etc, so I don't need advice there, just on its reliability.
Also, please refrain from comments about how stupid this might be etc, or why don't you just do this instead. I really want a flavored iMac with an intel itx board inside of it okay? And no lcd swaps, I don't like the way they look. I would be willing to spend money repairing the flyback transformer if I thought it was going to hold up and actually work with the motherboard. Am I going to run Windows? No, I'm going to use hackintosh patches and run Snow Leopard.
Here's why I want to know:
I've been wanting to try this project for a while, and finally started it. I have a Grape iMac 333Mhz, and I'm attempting to replace only the motherboard, hard drive and optical drive, while keeping the original crt screen, and power supply. Following some guides to install iMac motherboards in ATX cases, I was able to make a wiring harness that will adapt the iMac's power supply connector to a 24 pin ATX power supply connector, and it worked! Initially I tried with an Intel d945gclf2d, which is a dual core atom 330, with the 945gc chipset, but it wouldn't power on all the way. Using MacTracker, I discovered the the power supply in these is only 80 watts, so I tried the new Asus at3n7a-i, which is the same cpu, but with the nvidia ion chipset, which uses much less power than the 945gc. This board fires up just fine using the iMac's original power supply! Unfortunately, I wasn't able to get anything on the iMac's screen.
Before even buying a motherboard, I had tested the iMac's screen by hooking up a hd15 to db15 adapter that had come with an old mac radeon that I bought, connected to the vga out on my Lime iMac DV. It worked the first time, but then in later tests, I noticed a lot of flickering, and large black areas. I thought (hoped) that it was just the db15 extension cable I was using, but now the iMac will not display any video at all. I even tried putting it back together with it's original motherboard. I'm almost certain it's the flyback transformer from reading all kinds of information online, but I don't know if it's worth fixing for a couple of reasons. I suspect that even though I could get video from the vga out on the iMac DV, I still won't be able to get it from the itx board or any other vga output except one from an iMac G3. I suspect this because I could still get output from the iMac DV, even after I got no video from the itx board (I know the itx board works because I connected it to another screen). My other concern is that if I fix it, and I AM able to get the vga out on the itx board to drive the iMac's screen, that it will somehow over stress the flyback transformer and cause it to fail again soon after the repair.
Anyway, I was really excited and somewhat surprised that my wiring harness actually worked to power on the itx motherboard, but it was frustrating when the flyback transformer went out. Maybe something I did caused it. Probably.
I may end up trying this on a slot loading model in the end. If I fabricate a frame that mounts the motherboard under the optical drive (it will fit), and the hard drive in the back, I think it will work. They also have more power (150w) and more reliable flyback transformers. The wiring will be a nightmare, but I think I can handle it. The pinouts are well documented.
If anyone can advise me on whether it should be possible to drive the crt with the itx board, and on the flyback transformer repair, I would really appreciate it. I found an article on how to do it, including precautions regarding discharging the crt etc, so I don't need advice there, just on its reliability.
Also, please refrain from comments about how stupid this might be etc, or why don't you just do this instead. I really want a flavored iMac with an intel itx board inside of it okay? And no lcd swaps, I don't like the way they look. I would be willing to spend money repairing the flyback transformer if I thought it was going to hold up and actually work with the motherboard. Am I going to run Windows? No, I'm going to use hackintosh patches and run Snow Leopard.
