Dead flyback transformer- iMac G3

Hi,

Many of the iMac (slot-loading) G3 computers had various heat-related issues. The problem in this case does not have to be a flyback transformer. It could also be, for example, faulty capacitors or semiconductors, or bad solder joints. Because of the high voltages inside this type of computer, all work must be carried out by qualified personnel only. Dangerous charges can remain in circuits and components (such as CRT and capacitors) with the machine turned off and disconnected from the mains. In addition to this, many plastic parts may have become brittle with time. So, even if you could find an experienced technician, spending time and money on repairing an iMac this old cannot normally be justified. For safety reasons, stop using a faulty computer!

The specific vulnerable component in the slot-loaders is the "PAV" board ("PAV" = power-analog-video). As Jan states, heat is the issue. They are convection-cooled, not fan-cooled, and that was not a good design choice. It tends to bite those like you and me who like to keep old computers in service. The G3 iMacs, unfortunately, apparently have a expiration date.

With time, the PAV board gets baked by all that heat and fails. Trying to find a "new old-stock" PAV is like expecting to find unobtainium at the local convenience store. Anything on the parts market will be used/pulled and will have had the same baking experience as the one you have now. The failure rate of PAV boards over the years was such that the new ones were snapped up for repairs long ago.

Good question. The slot-loading iMac was designed in a different way. In this case, the air flow inside the case was supposed to be OK without a fan. Also, the operation is quite quiet.

You may want to look for a tray loader, but remember that these models can have their own problems.

For safety reasons, do not make any attempt to rebuild the computer. As mentioned before, if the computer is faulty, please do not use it.

It all depends on what you want to use the machine for.

For speed, Mac OS 9 would probably be the best solution. However, the built-in AirPort card (802.11b) can not use WPA security in this case. WPA or WPA2 could be made to work with all systems via an external wireless Ethernet bridge (or a Wi-Fi range extender with Ethernet bridge capabilities), though. All Mac OS 9 web browsers have difficulties with modern web pages (Classilla may be acceptable in some rare cases).

Mac OS X 10.3 Panther should allow WPA security with the AirPort card. The web browser difficulties are more or less the same as with Mac OS 9.

Mac OS X 10.4 Tiger is perhaps the most useful operating system for this computer, but also a bit heavier. A web browser such as TenFourFox should make many modern web pages accessible.

https://everymac.com/systems/apple/imac/specs/imac_dv_se_500.html

And this is only the slot loaders right

If the PAV board, that is my understanding. I've not owned or used a tray-loading iMac, but images show a different internal arrangement, but still no fans.

Hi Allan,

The tray-loading iMac G3 does in fact have a fan (can be seen once the logic board/drive assembly has been removed).

Jan Hedlund wrote:

Hi Allan,

The tray-loading iMac G3 does in fact have a fan (can be seen once the logic board/drive assembly has been removed).

Good info. Thanks Jan.

Steve Jobs never liked fans

Yes. I wasn't going to mention that but your are 100 percent correct. He did not want the original Mac to have a case that could be opened for service either.

How much is a PAV board on eBay...

You'll have to search ebay. I hardly have time to do my own searches!

and how would someone fix it? I wouldn’t fix it.... Do you know of any people who could?

These are international forums; getting a useful local repair recommendation is virtually impossible. Best to find an Apple User Group near you and ask of them. Click here: FIND A GROUP

What if I put a mini fan near it?

A fan DIRECTLY UNDER IT BLOWING UP (not "near) may help if the problems are intermittent. If the problems are there all the time, somethings already baked beyond hope of resurrection.

But for now it is decor in the “Man cave”...

But it will look very trendy! I kept our G3 Summer 2000 DV 400 even though it is in "limp-along" mode due to heat issues.

Do you still have OS9 installed? I've noticed ours works OK in OS9; problems show when I boot it to OS10.4