Splicing a DB25 cable

[dirkomatic]

For those of you who have spliced into a DB25 cable to wire your controls...  Are the wires inside colored or anything?  What is the best way to keep track of the individual wires for the pinout?

[mvsfan]

personally I wouldnt use solid color ribbon cable for wiring anything. But if you really must, get a wire tagging book.

with that said, some specialty companies make rainbow ribbon where every wire is a different color. Buy some of that. it solves so many problems later on when your wire tags glue dries up and they fall off.

or if your in the construction industry and are fortunate enough to be working on a building thats getting an elevator, try to get some of the elevator wire scraps off of the guy. i did. they just throw small lengths away.

its #22, its one cable assembly, and its stranded and has from 30-50 wires, and each one is a different color.

i used it for the Cp to the Ipac. neat thing is that its all one cable so you only have to strip off enough to spread it out across the cp to all your buttons, and then to the ipac, you break it out in other words, and it makes for a very neat installation.

[mvsfan]

oh also, with that said, dont ever use a solid wire like Cat 5 to wire up your cabinet even though its tempting dont ever use it on anything you plan on moving or shaking or taking apart later (and you will do this.)

solid wire has no flexibility at all and tends to break at your solder points or right at your spade connectors.

also thats one more thing i do for reliability. I dont use spade connectors for my control panels. they tend to get a layer of oxide between them or they get loose and then the buttons no longer work. I solder everything in. If your handy with it its also no problem to unsolder it.

also whatever you do dont try and solder the other end to your Ipac. If the Ipac (or insert keyboard controller here) fails, your screwed.

with that said ive also employed many quick connects in my system so everything breaks apart easy as a unit.

ive tried though to modulate everything as much as possible.

for example, if the monitor goes bad, it has quick connects and easy access from the front to pull it out and service it but if its really bad or something, the quick connect plug is soldered to the monitor itself so i will have to solder it on the new one before i plug it back in.

its very good indeed in my opinion, to have your whole cabinet break apart in sections for service. You just cant use too many molex connectors.  But when you have 60 or more wires all hooked up with cheap quick connects, it gives too much room for corrosion or loosening, and subsequently, failure.

[dirkomatic]

Ummm...  I didn't say ribbon cable.  I plan on using DB25 connections for a lot of stuff...  That said, I found an old printer cable I had and it looks like the wires inside are colored as I thought they should be...  should make it much easier for what I need to do.  Thanks!

[jholman76]

I like to use a multimeter to figure out what wire is what using the continuity setting. Just strip the wire and connect that to one of the leads. Poke around with the other lead on the pins until you find it. or vice versa.

http://www.texsoinstruments.com/blog/wp-content/uploads/2008/11/fluke-116.jpg

its the setting 3rd from the bottom. it looks sorta like two arrows pointing at each other. (just to the right of the setting this meter in the pic is on.)

When the circuit is complete, it makes a small beeping noise. Its useful for testing fuses, etc and this.

EDIT: here is a tutorial:
http://www.ladyada.net/library/metertut/continuity.html

joe

[dirkomatic]

Thanks!  I have a cheap multimeter which may work.  I'll have to check.

[mvsfan]

im sorry, i suppose. i was assuming you were using an old db25 paralell bracket plug out of an old pc.

truth is that db25s have been used for much more than that over the years.

My Snes backup unit ive had since i was a kid uses a double ended male db25 connector to communicate with a Pc to load games.

and it was also used in many many other specialized systems, like on a lot of automotive scanners.

these specialty cables are often indeed multi colored especially in automotive systems from my experience.

[mvsfan]

I also have a Willem programmer that makes use of this port.

[dirkomatic]

im sorry, i suppose. i was assuming you were using an old db25 paralell bracket plug out of an old pc.

truth is that db25s have been used for much more than that over the years.

My Snes backup unit ive had since i was a kid uses a double ended male db25 connector to communicate with a Pc to load games.

and it was also used in many many other specialized systems, like on a lot of automotive scanners.

these specialty cables are often indeed multi colored especially in automotive systems from my experience.

No problem...  I'm actually not very good at soldering and am using screw terminals everywhere I can...  I'm getting a few DB25 breakout boards and planning on using uncut cables as much as possible.  Good to know about the oxidation, though.

My current panel uses cat5 and I really haven't had many problems with it.  I guess it's not really soldered much, though.

[mvsfan]

my opinion on the best connector to use for a control panel is a molex power connector with 0.95 pins In just about however many pin configuration you want in a connector up to about 44.

DB 25 connector pins are very thin just like about any pc connector and require some level of prescision to get them to connect correctly every time.

sooner or later you will bend or break one.

power connectors on the other hand are much thicker and way less prone to breakage.

on my 2 player fighter panel, with a lot of extra buttons in various parts of the cabinet,  ive got 3 connectors to disconnect and then the panel comes right off.
Ive got the PS2 (and i dont mean playstation 2) connector going to the Ipac,
and then ive got two power connectors going to the other buttons and to the coin door.

I could actually combine those two into one but havent done it yet.

The admin buttons hidden on top all go to one connector and then the other connector goes to the coin door.

[Necro]

Actually, there was a discussion on here regarding Molex (that I started) awhile back.  Molex aren't made for multiple swaps, on the order that a swappable panel might receive, and aren't apppropriate for this kind of connection.  DB's, on the other hand, are built specifically for multiple uses.

[GaryMcT]

I'm terrible at soldering and have terrible eyesight, so I opted for a db25 cable for this sort of thing. Make sure the cable is fully populated. Use a multimeter to figure out which pin is which. The little addon alligator clips for the test leads can come in handy. There is color coding there, but I don't know if it is standard and some of them look alike to me.

You can buy a single male to female cable and cut it in half to get use out of both connectors.