Drew a schematic of all the TTY connections, similar to "Figure 5-7", but
with more detail and as many parts values as I currently know. Still need to
know the resistance of the reader-run relay to be able to design a reliable
replacement.
11/28/03
Tried to fix my second M706. Replaced the first FF in the divider chain,
but the clocking is still dead. Guess I'll have to replace the second, too.
Found out why my TTY printer is dead. The "Carriage Rear Rail" has fallen
off of it's mounting screws.
Filled up my JameCo shopping cart with parts for the M452 and W076
replacements. Always a shock when so many little bitty items add up to real
money.
11/25/03
Fiddled with a new design for reader-run. I still haven't figured out a way
to supply the needed drive, keep the component count down, and not add load to
the reader-run line.
11/25/03
Just to prove I could do it, I downloaded Focal '69 at 19200 baud. It took
6 seconds, and gave a zero checksum. Wish my 8L worked well enough to actually
*run* Focal '69. Guess now I can download and run some diagnostics to figure
out what is wrong, though.
11/24/03
Checked out the RS-232 side of the W076X -- it works. Shortened the pulse
length of the one-shot in the M452X and that got the input side working at 110
baud (output worked before). Tried setting 19200 baud, but it didn't work.
Eventually discovered I had swapped the wiring for 19200 baud and 4800 baud.
It works fine now at all the speeds (up to 19200) that I can set with
Hyperterm. So nice to use reliable RS-232 stuff instead of my half-dead TTY.
My cable for the LA36 finally arrived. Idiot seller sent it media rate.
Since when is a cable media?? Two months to get it here.
11/23/03
Spent a bunch of time converting this stuff into web pages so others can
see it.
Started this log. Typed up a "To Do" list, indicating what needs to be
done for the major hardware pieces in the collection.
11/22/03
Tracked the problem with the W076X to the BC05M cable I built, which is
now fixed. TTY input works. TTY is in such bad shape that I can?t see the echo,
but the print mechanism is activated correctly. Will have to switch to LA36
when connectors get here. Still no ability to test reader-run in real use.
Spent some time writing a documentation-sheet for the W076X to match the
one for the M452X.
Spent some time getting the W076 board description ready for the board
fabricator.
11/21/03
Built BC05M equivalent cable for testing W076X. W076X isn?t working ? only
2ma is available at the transmit loop, instead of 20ma. Odd, since everything
checks out when I measure it at the chips on the W076X.
11/20/03
Convinced myself to stop fiddling with the M452X for now and work on the
W076X. Still need to check frequencies against my M410s, and to decide whether
or not to rework the monostable to match DEC's design.