3 Jan
2014
3 Jan
'14
2:57 p.m.
On Jan 3, 2014, at 5:18 PM, cctalk-request at classiccmp.org wrote:
From: Ethan Dicks <ethan.dicks at gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Re: Need DEC BC80J-20 cable
Message-ID:
<CAALmimndRqNj0eDbaYdyFGz+VsO0pikpHK_1O5wn4R-n2eV5sg at mail.gmail.com>
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On Fri, Jan 3, 2014 at 1:35 PM, Al Kossow <aek at bitsavers.org> wrote:
That one looks to be 6' (BC80M06) which is the only length I've seen
in person. They also have a BC80M25 for three times as much.
I am sure I can find a place to fasten it, even if I have to modify
the braid (or the chassis) slightly...
Anyway I was thinking of just bending over and paying the $57.50.
Until I got to "standard 9-13 day shipping $15.00" and it goes up from
there. Postage rates have really gotten ridiculous and the companies
(except McMaster-Carr who are quite reasonable for shipping) are
adding on their profit too.
Perhaps I can locate some surplus multiple twisted pair cable and
carefully solder the ends to a header connector. There are 13(?)
twisted pair differential signals and the rest are no-connects or
grounds. As Henk pointed out, some of the trouble may be the 6' of
unshielded ribbon cable (which is also smaller gauge than the twisted
pairs)...
-Charles
BTW,
Continental Computers answered my quote request with they can
"let it
go for $145"... that's about four times what I expected to pay for
one!
The BC80M listed for 57.50 should work fine. You'll probably have to fiddle with the big
drain cable on the
controller end.
I remember that big fat braid. ISTR it was not easy to find a
convenient place to bolt that down on a BA23.
-ethan 
3 Jan
3 Jan
4:03 p.m.
On Fri, Jan 3, 2014 at 5:57 PM, Charles <charlesmorris800 at centurytel.net> wrote:
Anyway I was thinking of just bending over and paying
the $57.50. Until I
got to "standard 9-13 day shipping $15.00" and it goes up from there.
Postage rates really went up a year ago. I was shipping things 12-13
months ago, then *bam* double-digit increases.
Perhaps I can locate some surplus multiple twisted
pair cable and carefully
solder the ends to a header connector. There are 13(?) twisted pair
differential signals and the rest are no-connects or grounds. As Henk
pointed out, some of the trouble may be the 6' of unshielded ribbon cable
(which is also smaller gauge than the twisted pairs)...
6 feet?!? I must have read 6 inches (or I had a dust spec on my
screen ;-) That's a lot of unshielded cable to push those
differential signals side-by-side through. My RL8A had 4 to 6
*inches* of flat cable going into the RL8A, then the BC80J to the
drive.
Most folks who collect DEC equipment have a few of the 40-pin shielded
cables. They were used with so many devices. If you don't have one
spare, those shouldn't be expensive to find and try out.
-ethan
5:03 p.m.
New subject: Pertec drive cables (was Re: Need DEC BC80J-20 cable)
On Jan 3, 2014, at 16:03 , Ethan Dicks <ethan.dicks at gmail.com> wrote:
Most folks who collect DEC equipment have a few of the
40-pin shielded
cables. They were used with so many devices. If you don't have one
spare, those shouldn't be expensive to find and try out.
Speaking of cables, I'm going to need to make a pair of 50 conductor ribbon cables to
connect my Kennedy 9610 drive to my PDP-11/44. It uses the common Pertec interface, and
the cables will need to be many feet long to allow the tape drive or PDP-11/44 to slide
out of the rack. The original cables were shielded, and the tape drive manual says that
was for EMI compliance. I wonder if I will be able to get away with unshielded cables,
since new 50-conductor shielded ribbon cable isn't cheap.
--
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/
6:29 p.m.
New subject: Pertec drive cables (was Re: Need DEC BC80J-20 cable)
On Jan 3, 2014 6:14 PM, "Mark J. Blair" <nf6x at nf6x.net> wrote:
I made some ~6 foot Pertec interface cables out of plain 50-conductor flat
cable and also using 3M Twisted Pair Flat Cable, 1700 Series. Both sets of
cables worked well enough for me the few times I installed 2.11BSD or
RSTS/E from tape.
Speaking of cables, I'm going to need to make a pair of 50 conductor
ribbon
cables to connect my Kennedy 9610 drive to my PDP-11/44. It uses the
common Pertec interface, and the cables will need to be many feet long to
allow the tape drive or PDP-11/44 to slide out of the rack. The original
cables were shielded, and the tape drive manual says that was for EMI
compliance. I wonder if I will be able to get away with unshielded cables,
since new 50-conductor shielded ribbon cable isn't cheap.
6:35 p.m.
New subject: Pertec drive cables (was Re: Need DEC BC80J-20 cable)
On 01/03/2014 05:03 PM, Mark J. Blair wrote:
Speaking of cables, I'm going to need to make a
pair of 50 conductor
ribbon cables to connect my Kennedy 9610 drive to my PDP-11/44. It
uses the common Pertec interface, and the cables will need to be many
feet long to allow the tape drive or PDP-11/44 to slide out of the
rack. The original cables were shielded, and the tape drive manual
says that was for EMI compliance. I wonder if I will be able to get
away with unshielded cables, since new 50-conductor shielded ribbon
cable isn't cheap.
You should be--the connections on the standard 2x50 conductor Pertec
cable is that with the exception of a couple of lines on P2, ground
lines are interleaved between signal conductors. I run 10 foot/3 m
cables off of my drives with no problems at all.
If you're worried about shielding, just invest in a roll of aluminum
foil HVAC tape and stick to the ribbon cable. Overlap at the tape edges.
--Chuck
4006
days inactive
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cclist＠sydex.com -
charlesmorris800＠centurytel.net -
ethan.dicks＠gmail.com -
glen.slick＠gmail.com -
nf6x＠nf6x.net