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iMac DV SE No Power At All

ScreenSavers

ScreenSavers

macrumors 68020
Original poster
Feb 26, 2016
2,125
1,677
Bloomingdale, GA
I got an iMac G3 at an auction yesterday for $5. It is an iMac DV special edition, model M5521.

I got it home and plugged it in and it does NOTHING. No light. No click. Nothing at all.

I tried the reset button in the RAM cover (PMU reset), and I also tried replacing the PRAM battery. The old PRAM battery appears to be dead, but the iMac should still boot, bcs from what I understand, this isn't an "old world" mac, but either way, I replaced it with a new good one.

I know CRT's are dangerous, so I don't want to just rip it apart either...

I have found some others with the same problem online, but everything I find is so old, so I figured I'd just ask again.

Any help would be appreciated!
 
Most likely bad capacitors on the CRT power board. A bad CRT flyback often still allows a pulsing power light. Getting there involves extensive disassembly, and yes, removal of the CRT monitor. You need to rip it apart to fix that. I'm gonna try it on an Indigo in the near to distant future, if I can't fix it, at least I could make something cool out of the case. Mine does pop the speaker a bit when attempting to power up, but that's all she wrote. No power light either. Though I've read a thread on a different forum of a guy that did recap that entire CRT power board, and they did get it fully working afterwards. They had the same problem, no light, no nothing.

At $5, you didn't pay much, and maybe you can figure out something cool you could repurpose it for. I know it's sad, but that's what you get with capacitor plague era caps, and a fanless design that lets heat linger past already poor quality capacitors.
 
I'd call it quits if you're not willing to take it apart. Power supply is probably cooked and not worth the effort to replace on an iMac G3 unless you already had the part.
 
Hrududu said:
I'd call it quits if you're not willing to take it apart. Power supply is probably cooked and not worth the effort to replace on an iMac G3 unless you already had the part.
Click to expand...
It can be repaired by replacing all capacitors. But it requires extensive soldering work, there's a ton of them on the board.
 
Daniël Oosterhuis said:
Most likely bad capacitors on the CRT power board. A bad CRT flyback often still allows a pulsing power light. Getting there involves extensive disassembly, and yes, removal of the CRT monitor. You need to rip it apart to fix that. I'm gonna try it on an Indigo in the near to distant future, if I can't fix it, at least I could make something cool out of the case. Mine does pop the speaker a bit when attempting to power up, but that's all she wrote. No power light either. Though I've read a thread on a different forum of a guy that did recap that entire CRT power board, and they did get it fully working afterwards. They had the same problem, no light, no nothing.

At $5, you didn't pay much, and maybe you can figure out something cool you could repurpose it for. I know it's sad, but that's what you get with capacitor plague era caps, and a fanless design that lets heat linger past already poor quality capacitors.
Click to expand...


I'm not even getting any light on the power button though. It is like it's not plugged in. No chance of it being that PAV board?
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Hrududu said:
I'd call it quits if you're not willing to take it apart. Power supply is probably cooked and not worth the effort to replace on an iMac G3 unless you already had the part.
Click to expand...
I'm willing to take it apart. I just want to make sure I do it safely by discharging the tube first.
 
That's what I meant. The PAV board is dead, and a recap job should fix it. It's just that it takes a lot of disassembly, and CRT discharging, to get to it.
 
Daniël Oosterhuis said:
That's what I meant. The PAV board is dead, and a recap job should fix it. It's just that it takes a lot of disassembly, and CRT discharging, to get to it.
Click to expand...
So it's not worth it? I can't seem to find any PAV boards online anymore. I buy a ton of parts for other Macs, but they are obviously newer.

The PAV and the power supply are the same things on a G3, right?

Thank you for the help!
 
ScreenSavers said:
So it's not worth it? I can't seem to find any PAV boards online anymore. I buy a ton of parts for other Macs, but they are obviously newer.

The PAV and the power supply are the same things on a G3, right?

Thank you for the help!
Click to expand...
PAV = Power supply in the iMac. Its not hard to discharge a CRT, so I wouldn't worry too much about that if you're interested in getting into this thing. Whether or not its "worth it" is totally up to you. I personally don't find much value in iMac G3s unless its an original Bondi or maybe a 700MHz summer 01. There are a lot of other machines I'd choose to put the effort into before messing around with one of those.
 
The power supply is part of the PAV board (Power Analog Video)

I think there is a tiny LED on the logic board, near the drive connectors, so you can see it with the RAM door open.
It should light up when you press the power button. It should be visible, with the iMac upside down, and the door open.
Plug in power cord, then press and release the power button. The LED should come on.

The last G3 that I took apart (early 2013, I think) to attempt replacing the PAV just came apart. The top case is made of (lexan?), and was really brittle because of age and heat. All the little tabs that used to be flexible were now very easy to snap off, and most did for me. So even if you succeed with an electrical repair, the plastics will likely not be your friend.

As Hrududu said, most iMac G3s won't be worth the effort unless it has collector value (and not too many would qualify for that. The older tray-load CD models likely would survive a repair better than the slot-load CD DV models.
 
Check the power cord, too. Be surprised how many iMac G3s had faulty ones; I think it was a recall back in the day.
 
DeltaMac said:
The power supply is part of the PAV board (Power Analog Video)

I think there is a tiny LED on the logic board, near the drive connectors, so you can see it with the RAM door open.
It should light up when you press the power button. It should be visible, with the iMac upside down, and the door open.
Plug in power cord, then press and release the power button. The LED should come on.

The last G3 that I took apart (early 2013, I think) to attempt replacing the PAV just came apart. The top case is made of (lexan?), and was really brittle because of age and heat. All the little tabs that used to be flexible were now very easy to snap off, and most did for me. So even if you succeed with an electrical repair, the plastics will likely not be your friend.

As Hrududu said, most iMac G3s won't be worth the effort unless it has collector value (and not too many would qualify for that. The older tray-load CD models likely would survive a repair better than the slot-load CD DV models.
Click to expand...
Ok, too bad then. I guess it's toast. There are no lights on the Logic Board, even with the bottom cover off. I have tried many power cords.
 
ScreenSavers said:
Ok, too bad then. I guess it's toast. There are no lights on the Logic Board, even with the bottom cover off. I have tried many power cords.
Click to expand...
I've heard of some people ripping out the broken logic board and CRT and fitting a Mac mini and an LCD in it. Who else has done this, or what have you used your broken ones for?

I'd appreciate pictures!
 
Ok, so I took out the old parts from the inside of the iMac, mounted an LCD where the CRT was, and put the logic board and some other parts from a 2006 Core 2 Duo MacBook inside of the case. Now I have an "iMacBook." But at least it has wifi and an Intel processor. ;):apple::D
IMG_6127.JPG
 
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Thank you! It's really not that useful, but I love the way these macs look. I have an iMac G5 and a newer iMac, but they don't look the same, and you definitely can't modify the case.
 
MacCubed said:
I think the microphone port would be a better place. Just take the camera and stuff from the MB LCD and mount it
Click to expand...
Yes that's what I'm probably planning on doing eventually. It's not really that important, but I do want to mount some more USBs. Probably more than one.
 
ScreenSavers said:
Yes that's what I'm probably planning on doing eventually. It's not really that important, but I do want to mount some more USBs. Probably more than one.
Click to expand...
I would put the USB hub where the headphone jack is in the front, it would look much better!
 
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