A few days ago I posted that I expected problems similar to Sherlock's when I started to bring up my Mimeo 1. Well, I have got problems, but they are different from Sherlock's.
I tested the power rails before populating the board and they all seemed OK. I have now just populated the video section. Unfortunately, when I power up, I don't get any characters, just a flickery display in which you can sometimes get vertical stripes:
I can't find any obvious shorts or bad connections. All the IC pins look to be in place. Nothing is running hot (except the heatsink, which seems to be as hot as others describe it).
However, the 74166 at D1 is running pretty warm – much warmer than the other ICs.
It sort of looks (to my uninformed mind) like it might be a timing problem with the video output (so some fault in the area of the 74166 may make sense).
My understanding of electronics is pretty limited; so any pointers as to how to go about diagnosing this would be greatly appreciated.
Many thanks for looking.