Friendly reminder to any 5620 / BLIT owners...

Ethan Dicks ethan.dicks at
Mon Aug 10 19:48:58 CDT 2015

On Mon, Aug 10, 2015 at 4:41 PM, Ian Finder <ian.finder at> wrote:
> The battery in the teletype DMD 5620 is mounted in a very fatal position,
> and does indeed leak, as I learned this weekend.


> If you have not removed it, I would get on that now.

Thanks for the tip.  I just checked the Blit I received this summer,
and the battery is thankfully intact.  Zero voltage, but no leaks

> In fact, if you still have batteries in anything, you might be doing it
> wrong... ;)

I lost an A4000 because I _thought_ I pulled the battery, but I was
wrong.  :-(  It might be fixable, and I will try, but I'm expecting to
have to replace it.

Now I just need to find out why this Blit doesn't display anything
when I power it on.  The motherboard seems typical of AT&T products -
a massive grid of square-pad-vias and a number of
proprietary/private-label ICs.  The firmware is on 8 27128s.  In case
I might have bitrot in 30-year-old EPROMs, does anyone have backups of
the firmware I can test/reburn with?  The RAM is 1MB of soldered
Hitachi 50256s.  Probably OK but no easy way to test them.


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