View Single Post
Old 7th Nov 2020, 10:04 pm   #77
circuitryboy
Tetrode
 
circuitryboy's Avatar
 
Join Date: Jun 2012
Location: Bristol, UK.
Posts: 51
Default Re: I found it! A very sorry looking MK14.

Your photo shows 7442 at IC13. National Semiconductor used this initially in the Keyboard Kit addon but then changed to 7445 which sinks 80mA. (Did SoC ever supply 7442?)
A fault here might give the irregular scan. (But not the x0F invalid segments)
circuitryboy is offline   Reply With Quote