4054 in Sacramento

Monty McGraw mmcgraw74 at gmail.com
Wed Feb 26 19:49:50 CST 2020


I had my 4054A display stop erasing when you press PAGE key or BASIC PAGE

I found the 4054 Parts and Schematics Service Manual on bitsavers.org at

I've narrowed my issue using that manual to a 74123 one-shot multivibrator
that creates a short delay for the erase to complete.  I've got a 74123 IC
ordered and should get it this week.

When I upgraded my 4054 to 4054A with an F39 option kit - the MAS board and
the IO Board were both upgraded.  Those schematics aren't in the 4054
service manual.

Then I remembered my list of your documents at Living Computer Museum - and
there was an 4054A Update to the 4054 Parts and Schematics.
I've asked the Museum to scan the manual update and I'll post the scan - so
it can be saved on bitsavers.org too.

BTW - I plan to exhibit my 4054A with the 4907 floppy drive system at VCF
Pacific Northwest Festival at Living Computers Museum on March 21 and 22.


On Wed, Feb 26, 2020 at 5:38 PM Mark Linimon via cctalk <
cctalk at classiccmp.org> wrote:

> On Wed, Feb 26, 2020 at 01:57:24PM -0800, Bob Rosenbloom via cctalk wrote:
> > I hope I can get this one running.
> Good find!  Good luck!
> mcl

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