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Re: Cable building attempt
Mitchell Spector wrote:
"Michael J. Mahon" <mjmahon@aol.com> wrote:
Mitchell Spector wrote:
"Michael J. Mahon" <mjmahon@aol.com> wrote:
Mitchell Spector wrote:
I've had a Sony CPD-1302 monitor sitting on my floor about three weeks
now and unable to use it (or even test it) since its missing the video cable.
I'd like to connect it up to my Apple IIGS.
What I need is a 9-pin (DE-9 male) to 15-pin (Mac and IIgs) cable, or
alternatively a DE-9 to VGA.
I took an old Macintosh video cable and cut the connector off one end.
Inside there are 8 wires, 3 of which are thicker than the others (I'm
guessing they are for the pins carrying the red, green and blue signals).
Those are actually coax cables, so careful stripping them.
I had already stripped the coax wiring by the time I posted about it,
using a pair of nail-scissors. I managed to cut myself once or twice in
the process so I guess that is what your "careful" warning was about. :)
It would certainly apply! But I was actually talking about the
main difficulty in stripping shielded cables--keeping the shield
intact.
Of the thick cables there is: Red, Blue, Brown. There remaining thin ones
are: Brown, Red, Orange, Black and White. I'll have to rig up a homemade
continuity tester but I'm hoping the color coded wires could save me the
trouble. The best I could do for the DE-9 end is a PC serial connector which
has an IDC ribbon cable...the bits of wire are very thin but at least I can
visually trace which pins each wire corresponds to.
You could also use a PC serial cable with a 9-pin male-male gender
changer...
I found an old Macintosh serial cable with a male 9-pin connector, though
unfortunately it physically omits pins 2 and 3 so I went with the PC serial
cable instead.
I'm ready to splice the two together with tape (I've painstakingly exposed
the metal contacts in each wire) but I need to figure out the Apple cable
end first. In any case all this would just be something to test the monitor
out, I'd need a more permanent solution.
With careful work and some soldering, that *could* be a permanent
solution, but I get your drift.
You can use a continuity tester to trace which wires are connected to
which pins. All it takes is an AA battery, a 1-cell flashlight bulb,
and some wire.
Thanks for the tip! Your suggestion gave me an idea, I built a continuity
tester using two AA batteries (3 volts combined), a LED with wire leads, two
stripped garbage bag twist-ties and some tape.
And a series current-limiting resistor of about 100 ohms, right. ;-)
Nice McGivering!
I found myself without a VGA cable recently, and no way to get one
in a timely fasion--so I used paper clips to fashion jumpers from
the laptop's VGA "dongle" connector to the projector's VGA connector.
Sometimes you just have to improvise. ;-)
And It worked! Here are my findings about the cable wiring....
RED coax = 1, 2 (red ground, red)
BLUE coax = 9, 13 (blue, blue ground)
BROWN coax = 5, 6 (green, green ground)
brown = 11 (mono audio)
white = 4 (n/c)
red = 10 (n/c)
orange = 7 (-5v DC)
black = 3 (composite sync)
I matched them up to the Sony CPD-1302 pinouts, minus the Green and
Blue ground signal (they're supposed to go to pin-1, but that is also where
the Red signal is which is a problem). I'm pretty sure the G, B grounds are
necessary because all I could see is an inversed faint/ghosted image with
no color. Pin-2 needs to be separate from pin-1 for this to work, but they're
wired together on the pre-molded end.
Yes, that 1-2 connection is a fundamental problem.
It's good to connect the shield grounds together, just to improve the
high frequency grounding, but not having it wouldn't cause the symptom
you describe.
Something else may be wrong. How are you determining the pin numbers of
the connectors and corresponding them to pinout diagrams? It's easy
to get "front view" and "back view" interchanged and get wierdness.
Hmm, what if I purchase a Sony multiscan DE-9 to VGA cable (I think a
few places still sell them) and attach a Mac-to-VGA adapter on the end?
I'm assuming that would work. Even if I had the homemade cable wired
correctly, it really needs to be soldered and not spliced and taped--the
connection wasn't exactly solid.
That should work--assuming that the Sony finds the sync where it can use
it.
-michael
Music synthesis for 8-bit Apple II's!
Home page: http://members.aol.com/MJMahon/
"The wastebasket is our most important design
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