INMC News

  

April/May 1980, Issue 7











Page 5 of 39











This meant that most programs would run alright, but as Mastermind and Lollipop Lady both pick up data from the V.D.U. ram, this data would be read as incorrect even though it would be printed correctly on the screen.

After purchasing a new 2102 memory chip and fitting this in place of the existing IC20 all my troubles were over. Incidentally this fault also produces errors on the “L” command.

As “Doctor Dark” states in Issue 4 – just because the bit isn’t displayed it still matters.

Thanks anyway for your help.

Yours
R. Milton.
Folkestone, Kent.

FLOATING BITS

Dear Sir,

Many thanks for INMC News – keep up the good work!

An addendum to the “Memory Plague” report – I hit a couple of memory problems with the STATIC memories. First was a 2708 which “flipped bits” when it got warm, changing say 5A to DA in the Load program. Second was a 2102 which started to output a few bits of its own about 20 minutes after switchon. The result in my case was continuous printing of a random character. Changing this chip for one in the VDU RAM position gave a regular pattern of dots on the screen when the chip warmed up.

Both faults took ages to track down, as the whole system worked fine from cold; trouble shooting tool which finally solved the problem? – the wife’s hair dryer! The bright lads at Nascom were right about the 2708 but way off the beam on possible causes of continuous printing. Moral, keep changing the chips around – I had changed just about everything on the board except the RAM, as it worked perfectly in the memory tests!

Yours faithfully,
H.R. Thornton.
Largs, Ayrshtre.

MIXED FEELINGS

Dear INMC,

As a paid up member, I would like to praise the very worthy efforts of the committee in producing the INMC News. Every issue a gem and this is encouraging more people to contribute, even me. I must admit to mixed


This is an OCR’d version of the scanned page and likely contains recognition errors.











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