Stuff for tray-loading iMacs

Nothing of interest for slot-loaders here!

Firmware info for tray-loaders

Monitor flyback transformer problem (usual symptom: blank screen, iMac won't start up)

Firmware info for tray-loaders

Note that tray-loaders do not suffer from the same firmware/OS X problem as slot-loaders.

But to install and run OS 9 or OS X on a tray loader you need "firmware 1.2" which you can download from the Apple website: In theory you shouldn't be able to install OS 9 or OS X without doing this update.

If you are not sure whether your firmware is up-to-date, you can

Monitor flyback transformer problem

Although tray-loaders don't suffer from a similar firmware/video/OS X problem to the slot-loaders, they are much more prone to failure of the Flyback Transformer (FBT) on the Power/Analog Video (PAV) board. This is the transformer that steps up the voltage to the 20,000+ volts that the CRT needs.

The complete details on diagnosis of this problem - and repair, if you are so inclined - are on these excellent pages by Zachary Komon (update 2.1.2005: the macopz site is currently down ... here is a mirror of the relevant pages). Diagnosis is easy, but repair is not for the faint-hearted as working around the CRT potentially exposes you to life-threatening voltages, unless you take the necessary precautions.

The problem is caused by overheating of the MFT. The following suggestions have been made to help prevent it from happening: