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I wonder if that big 112-pin connector on the personality cards actually carries PCI signals. The AIO service manual says it does not. If that's true I'm asking myself why it has so many pins? The only way to figure it out is to take a closer look at a child card intended to be plugged in there...

I don't mean to sound arrogant but I still can't believe that those units aren't serviceable. It might be not easy or cheap but they are still standard switching PSUs so it should be possible to repair them. We may need to make a good repair guide first. There are really advanced tech guys...

Not especially a 8600 PSU, but I successfully recapped the Astec PSU from my Power Macintosh 6100. I got a good guidance at the Badcaps forum: https://www.badcaps.net/forum/showthread.php?t=62455 The most interesting topics discussed there are the choice of the replacement caps as well as...

All Beige G3 ROMs I've seen so far contain Open Firmware drivers as well as native drivers for soldered on-board ATI GPUs. Otherwise, those chips would not be recognized at all.

@trag Thank you for reposting the link to your ROM pinouts.👍 AFAIK, pin 122 of the Beige ROM DIMM tells whether 64bit burst access ROM is installed. "0" (low) means burst ROM is present...

CPU daugthercard slot sounds like a non-standard, machine-specific connector. AFAIK, Apple Catalyst boards don't offer something like that. While the Hammerhead memory controller provides some multiprocessing support there is nothing comparable in Platinum. Moreover, Catalyst-based boards come...

Which slot is your CPU card is meant to be put into? IIRC, a Catalyst logic board doesn't have any PDS or similar. It has a ROM SIMM slot instead, see the annotated logic board photo here. I can only speak for original Apple boards...

Can you boot it into Open Firmware and dump the device tree node for Heathrow?

Do we need new ROM SIMMs for that or is it possible to reflash old ones? BTW, I remember seeing a Wiki page with pinouts for various PowerMac ROM SIMMs. It looks like the page has disappeared. I can't find it anymore. IIRC, it was created by @trag but I'm not sure...

I only have two ROM dumps: 0x40F2 and 0x45F2. I never saw 0x45F1...

@Phipli Thank you for the device tree dump for your board. Judging by the revision-id property, it's still the same host IDE hardware.

IDE support in Beige G3 is provided by the Heathrow ASIC. The Desktop variant, ROM Release 0x40F2, uses REV 1 of the Heathrow ASIC. That's what the device tree node in OpenFirmware 2.0f1 displays for Heathrow: Please notice the value of the `revision-id` property that contains "1". Now...

Linux PPC includes a driver for Twin Turbo cards. Here its source code. Unfortunately, code quality is poor: for the most part it stuffs magic values into magic registers. Moreover, it looks like the driver only implements a dumb frame buffer. 2D/3D acceleration isn't even mentioned there. In...

Side question: what do we know about TT hardware, especially the 2D accelerator IC? Is there any developer documentation (white paper) for the chip?

@jessenator The TT Macintosh card has the built-in ROM that contains two drivers: a FCode one for running under OpenFirmware as well as a native PPC driver to control the card under Mac OS. I'm not sure if the latter implements 2D acceleration. AFAIK the card won't work in a Mac without proper...

Please find attached the annotated PM 7200 logic board. Kudos to @MrFahrenheit and @demik for providing the hi-res pictures as well as useful infos.

@MrFahrenheit U12 is indeed the Ethernet MAC PROM. The marking of the Motorola IC below the CPU is very blurry. I can't read it...

@MrFahrenheit I can't read the markings of the following ICs (marked with the yellow circle): The former must be a clock generator for the CPU while the latter is presumably the Ethernet MAC ROM. Can you tell me what's written on their packages?

@MrFahrenheit Crisp & clear images. Thank you a lot!

@Plasticoat The resolution and the lightning are great! Everything is perfectly readable. Many thanks for sharing it with us!👍