1986 Williams
"Pin*bot"
Repair and Maintenance Log
Jeffrey Zweizig Jeff Zweizig Jeffrey Zweizig Jeff Zweizig
10/13/06: Acquired game at the Whiterose Gameroom Show in York, Pennsylvania. 10/26/06: Re-soldered bad solder joints at the left coin switch (o6) and the ramp entrance switch (40). 11/07/06: New pair of matched locks. 02/04/07: Rebuilt high-voltage section of the power supply. All the displays suddenly died and I determined that I lost -100 volts. As usual I turned to the repair manuals at marvin3m.com. Look under the display section of the System 11 manuals. Once I got the power supply board out of the machine I determined that the 39k resistor R4 failed, but by then I had already got a complete rebuilt kit from Great Plains Electrinics (www.greatplainselectronics.com). I replaced all the components in the high-voltage section. The new set of components outputs about +/-91 volts as opposed to the original +/- 100 volts. The displays are a bit dimmer, however, their life span should be considerably increased. While I was at it I also replaced the big +5 volt filter cap.  
Before (left) and after showing all new high-voltage components. 
The original high-voltage output transistors are no longer available and the replacements have a different pin-out. The leads need to be crossed as shown. This only applies to the D-8345 power supplies found in sys-11 and sys-11a games. 02/11/07: Added remote battery backup. Instead of permanently soldering some sort of remote battery setup to the CPU board I made some battery place-holders out of 1/2 inch dowel stick. I like modifications that don't require any physical altercation of the machine. I saw this dowel stick idea in several places around the Internet. The new battery pack was from Great Plains Electronics. Since this company is a supplier of pinball electronic components, I was disappointed to find that the battery pack has an integral ON/OFF switch. The whole point of battery backup is to not cut power. I think the switch makes the pack less reliable then it otherwise could be. I set the switch to the ON position and covered the switch lever with a blob of silicon caulk. 
This picture shows how the positive battery wire is mounted to the end of the dowel stick with a screw and crimp terminal. The screw head becomes the positive terminal of the "battery". Don't forget to account for the height of the screw head when figuring the length of the dowel stick. Note the blob of silicon over the battery pack switch. Also shown is a plastic tool I got from Home Depot. The tool is for pulling large inline fuses, but is also great for pulling AA batteries. 
Here are the dowel sticks in place. Note that the board shows how each battery must be oriented, but does not show the location of +4.5 volts. Before removing the old batteries I used my volt meter to determine the position of +4.5 volts. I believe the orientation shown here would be correct for any System-11 board, but a System-9 board would be "up-side-down". |