TTL homebrew CPUs

Most did, I think. In the UK, GEC (who AFAIK are noting to do with the American GE company) sold special low-ionternal-resistance D-cells (we called them 'U2' size at the time) for this appliocation The problem with directly firing the flashbulb from the battery was that as the battery aged its internal resistance increased. In the end the bulb would fail to fire at all, but before, the lower current throug hthe ignitor fillament meant the bulb took longer to fire, messing up the synchonisation. Probably not a problem on the Speedgraphic/MPP Micropress shutters (large format focal plane shutters that took a good 1/4s to go across the film) Leica sold a flashgun which took ES cap flashbulbs or SCC (single contact small bayonet cap) with an adapter that was supplied with the unit. The original design used a special 6V dry batttery, this was quickly replaced by a holder that took 4 AA cells in series. Then there was a battery/capacitor module (22.5V battery) that fitted in place of that, making contacct with the battery terminals and the metal case of the flashgun (which was the connection between the bulb and sync contact). I've also got a SCC-cap flashgun that seems to have been designed for TLR cameras (from the bracket that came with it). It either uses a pair of C cells or a 22.5V baettery + a resisotr/capacitor module that was included with the unit. -tony