25 May
2012
25 May
'12
1:09 p.m.
On 05/25/2012 02:45 PM, Tony Duell wrote:
I'm not an expert by any means, but I've done some lathe work.
Yes, my HP PTR uses that method.
Yup, that's the one.
Compared to my ASR-33 it's a screamer.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
Yeah. :-/ I
have a small Sherline mill and lathe here...they're both
really beat up (not by me!), but I've obtained all the required
replacement parts and just need to sit down and work on them. I'd love
to do stuff like that when I get them running.
Be warned that using machien tools well takes a lot of practice. You will
not be able to amke a tape reader in your first week of using such
devices :-) I have a
really hard time getting excited about a manual-pull paper
tape reader, though; I'd have to investigate some sort of power feed system.
The traditional way is to use a capstan and pinch roller, as in a tape
recorder. This gives constant speed, of course. The captan normally turns
continuously, the pinch rolelr is engaged by a solenoid to start the tape
moving. There was normally a brake, nothing more than an electromagnet on
one side of the tape and an amrature plate on the other side that grips
the tape when the electromagnet is energised, to stop the tape. I have an
optical PTR on one of my PDP-8s; it's an HP unit with a
homebrew board on the back that gives it a positive I/O bus interface
Possibly an 2748? I'ev got one on my HP9800s. There are a few pictures of
it on the HPCC ewb site... talk to the
8/e. That works nicely, and it's very fast. That, however,
is staying on the 8/e.
I didnt think it was _that_ fast.