The power supply:

Overview photos:

wrt the psu connectors similar to the P8,P9 and whatever that third one is called, take a multimeter and the ISA & PCI pinout and measure which pin goes to which voltage pin on the isa & pci slots.

Interesting that the board is 4 layer, but Cache module 6 layers 😮 and they stuffed all SRAMs on one side.
its Celebris XL-5100 Digital equipment's celebris XL 5100 has black screen and gives out an error code. last post includes documentation, those are on the spare parts list
54-23532-01 54-23532-01 Module, 256K Asynchronous Cache
54-24070-06 54-24070-06 P54C-100 CPU Card w/0 CPU

theretroweb entry is wrong listing it as 440FX https://theretroweb.com/motherboards/s/dec-ce … ebris-xl,-xl-dp the board itself doesnt have a chipset 😀 chipsets are on CPU cards

rasz_pl wrote on 2024-02-17, 19:28:

Interesting that the board is 4 layer, but Cache module 6 layers :o and they stuffed all SRAMs on one side. its Celebris XL-5100 […]
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Interesting that the board is 4 layer, but Cache module 6 layers 😮 and they stuffed all SRAMs on one side.
its Celebris XL-5100 Digital equipment's celebris XL 5100 has black screen and gives out an error code. last post includes documentation, those are on the spare parts list
54-23532-01 54-23532-01 Module, 256K Asynchronous Cache
54-24070-06 54-24070-06 P54C-100 CPU Card w/0 CPU

theretroweb entry is wrong listing it as 440FX https://theretroweb.com/motherboards/s/dec-ce … ebris-xl,-xl-dp the board itself doesnt have a chipset 😀 chipsets are on CPU cards

Thanks! Indeed I did see this board on theretroweb, but got confused by the chipset mentioned in the properties overview.

These are a bit of a weird machine and there isn't a whole lot of information out there about them and even fewer photos.

In the first half of the 90s DEC had the DECpc MT, MTE, MP, XL and XP which I believe all used variations of the same basic tower case (photos are hard to come by to confirm). Some of these had the CPU on a card for easy upgrades, and least one of them (the XL) had an Alpha CPU as an upgrade option. When the DECpc brand was retired, some of these machines appear to have been sold under the "Prioris" brand for a little while. The Prioris XL and LX use the same kind of case but I don't know if they were new machines or rebranded older models.

The Celebris XL comes from that general mess. It came out in October 1995 after the rebranding was finished and seems to be the successor of the DECpc XL inheriting its CPU upgradability. It appears to use the same basic case as the earlier machines but with a different plastic front that hides the upper half (drives and power button) behind a door. The Celebris XL was also sold as the Alpha XL with, by the looks of it, the only real difference being the CPU card (Alpha instead of x86) and I assume the firmware on the motherboard. DEC also sold Alpha upgrade kits for the Celebris XL as they did for the previous DECpc XL machines.

So this is why the weird PSU, why everything CPU-specific is on the CPU card, and why some of the stuff about it on TRW mentions Alpha AXP. The Celebris XL service manual doesn't mention that ATX-looking connector at all and so presumably doesn't use it, but the Alpha XL manual says its all 3.3v - I guess for the Alpha CPU (other Alpha workstations of around that age also have a pile of extra 3.3V from the PSU).

I wouldn't be surprised if the Prioris XL used the same CPU cards as the Celebris XL. The motherboard is a bit different though - EISA rather than regular ISA, crappy onboard video and perhaps better onboard SCSI.

Celebris XL service manual: https://www.zx.net.nz/documentation/mds-19990 … pc/a0823svb.pdf