On 2020-Jul-28, at 6:40 PM, Jay Jaeger via cctech wrote:
> On 7/28/2020 1:43 PM, Brent Hilpert via cctech wrote: >> >> Per the OP's machine, the early HP21xx machines were based on CTµL, for >> which the main supply is +4.5V. >> DTL and TTL chips in these machines ran off that 4.5 supply. >> > > The DTL I referred to in my posting are in a third-party (IOMEC) disk > controller, not the HP 2114 CPU. Oh, I take it you mean in a separate chassis with it's own power supply then. (I thought you were referring to the interface boards in the CPU chassis).