Vt100 style keyboard repair, and etc. - VMS

This is a discussion on Vt100 style keyboard repair, and etc. - VMS ; Greetings enthusiasts: I've been going through dad's collection of VT100 and CIT101 terminals looking for ones that work (see http://www.fpns.net/willy/pdp11/forsale.htm ). It is a bit depressing, but almost half those I've tried seem dead now, and I tested them all ...

+ Reply to Thread
Results 1 to 2 of 2

Thread: Vt100 style keyboard repair, and etc.

  1. Vt100 style keyboard repair, and etc.

    Greetings enthusiasts:

    I've been going through dad's collection of VT100 and CIT101 terminals
    looking for ones that work (see http://www.fpns.net/willy/pdp11/forsale.htm).
    It is a bit depressing, but almost half those I've tried seem dead now, and
    I tested them all OK about 5 years ago. Sigh, problems include: functional
    transmit but black screen, another where screen and recieve work but
    transmit seems to be trashed, and a couple CIT101 where everything
    but the keypress for one or two keys works. I'll do some board swapping
    and probably get one or two more working. However I'm curious if any of
    you have taken a keyboard apart? Is it possible to clean the contacts?
    I have lots of spare VT100 keyboards, but the CIT101 was different and
    I don't have spares.

    I also have several RX02 drive units where DY0: won't read, but DY1: does.
    I assume this is a use issue, any suggestions? Simple head cleaning?

    Finally I've added one more item to the 'forsale' page:

    Model: 906II-1-X8972
    Magnetic Tape Handler
    Potter Instrument Co. Inc. Plainview, NY

    I can't believe anyone wants this, but if you have even heard of it I'd be
    interested.
    Its huge, came with monster power supplies.
    Its likely to go to the dump next month, so no reasonable offer ( >= $1)
    will be refused!

    Will


    --
    No virus found in this outgoing message.
    Checked by AVG Anti-Virus.
    Version: 7.1.362 / Virus Database: 267.12.8/165 - Release Date: 11/9/2005

    ----------
    To unsubscribe (or subscribe) from (to) this list, send a message to
    info-pdp11-request@village.org, with the first line of the message
    body being "unsubscribe" or "subscribe", respectively (without the quotes).

  2. Re: Vt100 style keyboard repair, and etc.

    I've repaired many cit101s. Keyswitches are pretty easy to desolder
    and replace - they're sealed and I could never clean them successfully
    - but before you do that, *really* lean on the ones that don't work.
    That seems to break through the oxidation and doughnut crumbs.

    As to failing to send or receive, look on the logic board for chips
    marked 1488 (driver) and 1489 (receiver) down near the d-sub
    connectors. There are several, but you want the ones that connect to
    pins 2 and 3. They're incredibly difficult to desolder - I've thought
    at times they were brazed in place - but replacing them always fixed
    the problem. I always put sockets in their place, and in fact, the
    later cit terminals came with those chips socketed.


+ Reply to Thread