I believe only 2 are known... They're not hard to put together. The boards go into the cardcage with the chips facing the RHS of the machine, and the boards are keyed so they can't go in the wrong slots. From the left, the slots are : CPU Option (nearly always empty, although a few hackers put a tape streamer card in there), CPU, Memory, EIO, OIO. The EIO board has 2 50 pin edge connectors on the front. The top one goes to the floppy drive (normal SA800 connections). The bottom one goes to the DIB (Disk Interface Board), and thence to the hard disk. Ignore the front connectors on the CPU board unless you have a logic analyser and want to trace the microcode. They're the microcode address and data lines, bascially. The OIO board will also have front connectors. The top 2 (50 pin) are the PERQlink parallel interface. The bottom one is normally not used, but I've hacked mine to be a QIC-02 streamer interface. You can generally ignore those. The landscape monitor is a Moniterm chassis. They are _very_ unreliable. The CRTs lose emission, the EHT blocks (a partially-potted module, there is no schematic in the official service manual) fail too. I must do a workarounf for the latter sometime. The KME Portrait monitors (as on the T1s) are a lot more reliable. -tony