PDP-11/45 RSTS/E boot problem

Fritz Mueller fritzm at fritzm.org
Thu Feb 7 00:37:54 CST 2019

> 4116 datasheet specs 2mS, my calcs give a refresh period of 1.5mS, the 14.5uS from the manual would give 1.86 mS, 7% shy of 2.
> The schematic specs 1% resistors, and the parts list does appear to spec a high-tolerance "1%200PPM" cap.
> Although there are the internal voltage divider Rs in the 555 which are also critical for the timing and everything is 40+ years old.
> Idle speculation at my distance, we'll see what Fritz observes.

Brent:  11.8us, 6.4us position 
Manual: 14.5us, 6.0us positive
Actual: 15.2us, 8.5us positive

So yeah, a little pokey there...

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