It's time to post some pictures, I think.
I have finally managed to install all the major parts of my computer in their new home. Here are some pictures but I will eventually put higher definition ones on my own website.
On the left are various provisional power supplies and stacked boxes containing PCBs and other parts. The provisional voltage regulator and current monitoring panel is on the back wall mostly hidden by the two backplanes. On the right is the control panel with the provisional power supply for its lights . . . and more blue boxes. This layout should give me enough space to work on any part of the machine. I haven't connected all the cables yet.
This is a better picture of the regulator panel and the back of the backplanes.
At the front of the backplanes the entire main memory unit is now installed complete with the guide rails for the PCBs. At present I can only operate the main memory for short test periods until I have installed the cooling fans with their housings. Above the main memory are the first few PCBs for the control memory. One of my pending tasks is assembling the rest of these. Although I am currently only installing circuits on the first backplane I have already installed the second backplane above it so that I can use it for temporary test circuits. An advantage of wire-wrapped backplanes with plug in PCBs is that temporary circuits can be built quickly and then stripped out when no longer needed.
This closer picture of the PCBs shows how essential the guide rails are to keep the boards at the right spacing and allow air from the fans to pass between them from one end to the other. In reality during normal operation the backplanes in a complete machine are mounted inside the cabinet with the PCBs vertical and the fans at the bottom but they are rotated out of the cabinet into the position as above during maintenance, so I will locate the fans on the right hand side. In my design the PCBs that generate the most heat are all on the left side, so at the top when eventually put inside a cabinet . . . some time in the distant future maybe!
This picture clearly shows the ventilation slots in the PCB guide rails as well as the original H200 control panel now properly mounted on a worktop with its lighting power supply beneath and some of the lights working. Fixed in a corner close to a wall like this the panel would not appear to be in a convenient location for any work to be done on it but . . .
. . . it is actually mounted on a hinged section of the worktop and can be tipped face down to give access to the interior and the cable connectors underneath it. It is heavy and I am getting tired of lugging it about so this arrangement will save me a lot of effort if anything inside it goes wrong in the future.
Having set up the major elements of the machine in a way that enables me to access them easily and connect them all together, I can hopefully now focus what time I can spare for the project onto getting on with the actual electronics side of the work again, which will please my aching back no end. Actually as my wife helped me position the heavier items she will be pleased as well and has now returned to breaking her back doing gardening, her own chosen form of self-torture, our weather and seasons here in the UK no longer conforming to the traditional expectations of gardeners.