using new technology on old machines. Was: PDP-12 Restoration at the RICM

Ah, 'there's not the time to do it properly, but there is the time to do it again'. Why not do it properly first time? What is the rush in bringing up a classic computer? And for a test, use the TTL pulse generator you have on your bench. Or even an NE555 astable (yes, with a decent capacitor it is stable enough for a baud rate generator, I've used it). Heck, I've worked on machines that used a 2 transistor astable multivibrator for the baud clock. Surely you have 2N3904s in the spares box? Incidentally, if certain horologists heard you would use MDF in an antique clock, you would be going home with a pendulum rod shoved where the sun don't shine ;-) 'Full stock of TTL parts' ??? You make it sound like I am suggesting using lookahead carry generators, parallel multipliers, Excess 3 to 1-of-n decoders and the like (all of which exist(ed) in TTL). No, I am suggesting using some very common counter and gate ICs. How are you going to fix a TTL-based machine like your 11/730 without spares and without knowing what the ICs do? It is cheating :-) More seriously, tools are one thing. And had it been suggested that as a quick fix you took the TTL output reasonable (even if said sig-gen contained many times the number of components of the rest of the machine). But to make a custom solution that is over-complicated IMHO is the wrong way to do it. You might well inject your HP sig-gen into the mixer (first detector) stage of your WW2 radio to get it going if the local oscillator had failed, or if you didn't have the right crystal, or whatever. But I hope you wouldn't replace the valve (tube) based local oscillator in such a set with a digital synthesiser as a permanent 'repair' -tony