I have brought my SWTPC 6800 system back to life that I built as a kid in 1976. It is pretty heavily loaded with RAM cards, floppy controller, etc. and the 8V power supply rail was never really able to hold its own. It sits at about 6.5V now... driving many 5V regulators on the various cards. No where near enough margin going into those.

2) add a new transformer to the existing supply just for the 8V rail. This will also fit but requires moving the existing transformer, cap, DC distribution board-- all efforts that require drilling new holes in the chassis. This would be a more authentic solution since I wouldn't be introducing power supply designs that didn't exist back then. There were actually published mods along these lines in the day but I am little hesitant to butcher the chassis to accomplish this.

I have brought my SWTPC 6800 system back to life that I built as a kid in 1976. It is pretty heavily loaded with RAM cards, floppy controller, etc. and the 8V power supply rail was never really able to hold its own. It sits at about 6.5V now... driving many 5V regulators on the various cards. No where near enough margin going into those. So, I am contemplating the following, 1) rebuild entire power supply using three switchers, 7.5v unit nudged up to 8V and two 12V units to supply +/-12 on the backplane. All of these will fit inside the original cabinet in place of the linear supply's transformer, giant electrolytic cap, bridge rectifier, etc. I'd mount these switchers to an aluminum plate that would fit into the chassis and use existing mounting holes thereby not drilling any new holes in the chassis. This would be the least "period" solution but allow all of the original cards to run in the machine with power to spare. 2) add a new transformer to the existing supply just for the 8V rail. This will also fit but requires moving the existing transformer, cap, DC distribution board-- all efforts that require drilling new holes in the chassis. This would be a more authentic solution since I wouldn't be introducing power supply designs that didn't exist back then. There were actually published mods along these lines in the day but I am little hesitant to butcher the chassis to accomplish this. 3) scuttle the legacy RAM cards, most of which are 4K in size built with 2102's... and one 16K built with 2114... and replace them with a single homebrew RAM card using one 32Kx8 SRAM drawing almost no power in comparison to these old cards. Definitely not period and all the authentic RAM cards would be sitting on the shelf then but the power supply could remain unmodified. Any recommendations on the best choice?