Replacing your Williams ROM or Wedge 40/20 pin ribbon cable

is one of the best things you can do to your game.


After 20 some years of having been disconnected, reconnected at least a few dozen times and laying around in some box getting brittle, all ribbon cables on these Williams boards need to be replaced. When I get any ROM or wedge PCBs in for repair the first thing I do is replace this old worn out ribbon cable with a new cable and connector. The ROM board uses a 40 pin ribbon cable and the wedge boards uses a 20 pin ribbon cable. If you need to buy any ribbon cable get a 40 pin cable long enough for both ROM and wedge board. After cutting the proper length pull one of the halves in half so you have a 20 pin cable for your wedge board. The cheapest and most readily available 40 pin cable you can buy is the same type used in computers for the hard drive ID cable. If you want to reuse the cables that come from an old PC's HD (40 pin) and floppy drive (20 pin), make sure they are still in good shape or else you're swapping old parts with old parts.


Before removing the old cable first mark the connector you are removing, this will assure easy installation later. Use a real tiny flat head screw driver to pry up or push aside the side taps on the ROM/wedge board connector. You want to take great care not to break off the tabs or you'll be resoldering a new connector onto the PCB. On most ROM boards there are side tabs you need to push (pry) to the side. On most wedge boards you need to pry up on the connectors housing. After the top of the connector is off remove the ribbon cable by pulling up on it slowly.


After you removed the ribbon cable inspect the pins to make sure you didn't bend any of them. Also look at your top housing making sure you didn't break the tapes on the sides off.


Next cut your length for new ribbon cable. Make sure it's a straight cut, using scissors will not do. You need a paper cutter or similar to assure it's perfectly straight. If you don't get a straight cut or align the cable crooked, after reconnecting the cable the pins could cut into the wire next to the intended wire, causing a short and making your work useless:


After you have a perfect straight ribbon cable center the ribbon cable in position on the header. Push the top of the connector you took off earlier onto the cable and hold it in position. Make sure to line up the mark that you placed on it earlier. You can now align the edge that you cut perfectly straight with the top of the connector. After the cable is aligned hold the top onto the header with your fingers and place a soft piece of wood on the back side of the PCB as pictured below. Use a vise and clamp it into place. Make sure the back side of the PCB is only on the wood protecting it from bending any pins on the PCB. Now close your vise and press the top of the header that you removed earlier back onto the PCB. Make sure the ribbon cable is still in position and clamp away:

(note: make sure any parts like capacitor are out of the way of the vise like in picture above that could get damage as you close the vise.)


If you need to add a ribbon cable socket just make sure it's on straight and clamp away:

Now your PCB ribbon cable should be good for another 20 years.


If you need any parts for the above self help go to my parts page.