Fixing a DEC Letterwriter (LA100)

Steve Maddison steve at
Thu Jun 12 13:54:19 CDT 2008

2008/6/12 M H Stein <dm561 at>:
> Can't suggest where to start checking but I do have several RO LA100s
> awaiting the trip to the scrapper, in case I can help with any non-kbd parts
> before they go.

I may take you up on that if repairing the existing bits is going to
be messy. I could definitely use some of the plastic studs that hold
the case together - unfortunately I only figured out that you're only
meant to remove the centre part after persuading the entire thing out
with a screwdriver...

> I do also have the tech manual somewhere; unfortunately IIRC it's on 17"
> paper so I can't scan it.

I have since found the full print set on, so I'm all set on
that front. I've started tracing back from the logic controlling the
LINE and CTS indicators but haven't found anything obviously wrong as
yet. I have however read some funny-looking voltages off the 7406 in
this part of the circuit: 11.something volts while the datasheet says
30. Could of course be down to my test equipment as I'm limited to a
basic digital multimeter at the moment.


Steve Maddison
"Hardware: (n.) the parts of a computer you can kick."

More information about the cctech mailing list