31 Oct
2021
31 Oct
'21
6:55 a.m.
On Sat, Oct 30, 2021 at 11:25 PM Tony Duell <ard.p850ug1 at gmail.com> wrote:
On Sun, Oct 31, 2021 at 6:15 AM Josh Dersch via
cctalk
<cctalk at classiccmp.org> wrote:
Yes, this matches what the service docs explain, sounds like the same
machine.
Hey all --
I picked up a GE Terminet 300 which appears to be mostly functional, but
is
in need of alignment -- it's printing fairly
smudged garbage with a few
recognizable characters intermixed. Character positioning (horizontal)
seems to be fairly irregular, for the characters that print clearly.
The unit has suffered some knocks in its life and it's clear the
photocell
board has come slightly loose, which I'm sure
is not unrelated, so I'm
studying the service docs to get a better idea what's going on. There's
an
alignment gauge which I could reproduce if I had
any idea what it's specs
are. The service docs are a bit vague and the photocell assembly is a
bit
difficult to see, buried beneath the print band
on the left hand side.
Anyone out there have any experience with these? Any wisdom to impart
here?
I think this was badged 'ICL' in the UK, I have a couple (118
characters/line KSR and 75 charaters/line RO) but it's been several
years since I worked on them.
From what I remember the photocell unit is the main timing sensor. It
detects the bottom tabs of the print fingers, the start finger of each
set has a wider tab spot-welded to it (and thus that finger can't be
removed from the belt) which gives a wider pulse that's detected by
the electronics.
If the photocell unit is not in the right position laterally but still
gives good timing pulses, the thing will work but won't hit the
fingers cleanly. You should still get the right characters, or perhaps
the one before or after on the belt if it's way out of position. But
if it's not producing clean pulses all the time then the thing may
print random characters.
A missing finger is bad news for that reason, The missing timing pulse
may well confuse the electronics.
I should have been more clear -- only the top of the finger is missing, the
bottom is still present, so it should in theory be generating proper pulses.
I should see if I can pull the assembly out and clean it, I suppose if the
optical sensors are dirty it'd be a problem.
- Josh
-tony
Also, anyone have any spare print fingers? My print band's missing one
(a
"9") and I suppose it wouldn't be a
terrible idea to have a few extras
just
in case...
Thanks,
- Josh