UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Nascom repair

cosmocat · 24th Oct 2017, 3:57 pm

Looking at the screen shots again the 2 lines of garbage are the same on both pictures so that looks like uninitialized ram content. It looks like the video RAM is being read correctly ( so all the address counters in the video section are working ) but not written to. Also the 2102 memory chips hold 1 bit each so a faulty RAM chip could not produce that pattern.

24th Oct 2017, 3:57 pm	#8
cosmocat Triode Join Date: May 2011 Location: Bristol, UK. Posts: 35	Re: Nascom repair - Looking for clues please Looking at the screen shots again the 2 lines of garbage are the same on both pictures so that looks like uninitialized ram content. It looks like the video RAM is being read correctly ( so all the address counters in the video section are working ) but not written to. Also the 2102 memory chips hold 1 bit each so a faulty RAM chip could not produce that pattern.