I must admit that I'm starting to get confused myself but unless I hear
otherwise I'm going to stick with my original opinion (Oct 17) that the DIP pin
1 should connect to the IDC header pin 1 which would connect DIP 29 to header
24, not 23. Sounds like your cable connects DIP 1 to Header 2 etc.
Correct ? Yours?
DIP IDC DIP IDC
1 1 1 2
2 3 2 4
3 5 3 6
4 7 4 8
5 9 5 10
6 11 6 12
7 13 7 14
8 15 8 16
9 17 9 18
10 19 10 20
11 21 11 22
12 23 12 24
13 25 13 26
14 27 14 28
15 29 15 30
16 31 16 32
17 33 17 34
18 35 18 36
19 37 19 38
20 39 20 40
21 40 21 39
22 38 22 37
23 36 23 35
24 34 24 33
25 32 25 31
26 30 26 29
27 28 27 27
28 26 28 25
29 24 29 23
30 22 30 21
31 20 31 19
32 18 32 17
33 16 33 15
34 14 34 13
35 12 35 11
36 10 36 9
37 8 37 7
38 6 38 5
39 4 39 3
40 2 40 1
m
----- Original Message -----
From: Brian White
To: [email protected]
Sent: Monday, October 23, 2017 10:11 PM
Subject: Re: [M100] DVI cable
My order from Phoenix came in.
http://www.king-cart.com/phoenixent/product_name=HWS15322
http://www.king-cart.com/phoenixent/product_name=HWS1877
http://www.king-cart.com/phoenixent/product_name=HWS16014
I have determined that:
* The DIP connector above IS the kind that connects pin1 to conductor2.
* If you crimp the two connectors above straight-through with no twisting
pairs of wires or other tricks to get the pinout flipped, that results in a
cable with the right wiring, at least according to the tech/service manuals for
both M100 and DVI.
I have some pictures here so you could make the cable by just visually
matching up the orientations of the connectors and cable:
http://tandy.wiki/Disk/Video_Interface
One of the pictures there is I took the bus pinout drawings from both
manuals, and added another drawing for dip40 for the m100 side, so you can
easily figure out or verify a cable, ignoring any theories about flipping pairs
or which way the cable should go into a connector etc, you just go from pin to
pin, by number, with the drawings for the connectors so you know which pin
actually is pin6 on both connectors etc, so you can match up the *signals*. for
certain.
So I have verified that these parts crimped this way, results in a cable that
for example, pin 29 on the Model 100 goes to pin 23 on the DVI.
(The WR pin goes to the WR pin.) Same for everything else.
HOWEVER
I can't say I actually used it successfully. I followed the boot sequence in
the DVI manual and the DVI presents the first two prompts on my monitor, the
disk drive makes a noise briefly, the disk drive light comes on, all as the
manual says to expect. But when I insert my boot disk and close the door latch,
nothing ever happens.
My boot disk is an original not a copy, so it might be corrupt from age but
at least I know it's not simply mis-labeled or a bad copy.
I still have another M100 and a T102 I could try, including a home-made T102
cable that came with the unit. (someone butchered it out of an IDE cable.)
One symptom that shows something somewhere is wrong, is that when I turn on
the dvi, usually the m100 does something bad. Sometimes the M100 screen goes
blank, sometimes it simply freezes (the clock stops counting), sometimes 2 or 3
of the character cells on the M100 screen get scrambled.
With the dvi cable unplugged and then cold-start, the M100 behaves normal and
seems to work fine, and displays the same free ram.
I haven't verified that the system bus is still functional, but I can. I have
a PG Designs 8-bank ram upgrade that goes in a M100 bus connector.
The M100 even acts normal after a cold-start even with the cable and dvi
connected, before turning the dvi on.
--
bkw
