Collinsville, IL
I read many threads here about problems people are having with their early SS games. It seems like most of the problems are connector related. I am NOT a tech-pro but I have re-built over a dozen Stern – Bally and Williams games. To insure you have a solid and lasting game you must make sure you have good voltages and connectivity throughout the entire game. You could just replace a faulty part or connector and get the game working again but down the road some other connector will fail and you’re back to the workbench.
My method is nothing new – it’s covered on Pinwiki as well as several other sites. I suggest going to those sites for more detailed information.
First you must have reliable voltages. This starts with the rectifier board. I remove the entire transformer and rectifier board as a unit and work at the bench. In some games they’re mounted on a plywood base in the bottom of the cabinet – others on a metal bracket in the back-box. The original bridge rectifiers are undersized and must be replaced. Also replace the header pins – don’t just re-flow the solder. They’re old and probably burnt. Inspect the high voltage diodes and ceramic resistors. If they look suspect replace them now. It’s easy with the unit out. Also look at the fuse holders and replace if they look discolored or corroded. Check that they hold the fuse firmly. Replace if necessary. Lately I’ve been replacing the entire board – nvram. weebly.com has both kits and assembled boards at a reasonable price. After the re-build I check the voltages at the bench by connecting line voltage to J2 pin 6 and 7. Then check the output voltages at the test points. Take into consideration that nothing is connected. Next replace all the crimp connectors on J1, J2 and J3. This is very important but often overlooked. You’ll never have good connections with 30 year old connectors.
Next is the driver/regulator board. Replace all the header pins. Be careful removing the old headers – the solder pads are very fragile. (I just saw a thread with good tips on removing headers). Next replace the 5 volt capacitor (C 23) and the high voltage capacitor (C 26) Also add the ground and 5 volt mods as in Vid’s guide Bally/Stern driver board repair. Inspect for any burnt or damaged components – replace as necessary. Check the back side for any damaged traces. Again replace ALL the crimp connectors. J1 and J5 only have a couple of wires connecting to them. I usually add a couple of extra crimp connectors to the empty pins with no wire attached. This will help keep the connector seated. Install the board and connect J3 only. Check the voltages – they should be pretty close to specs at this time. Be careful with TP2 and TP4 – These are high voltage.
Next is the MPU. This board is subject to a lot of corrosion. First remove the battery then thoroughly inspect everywhere for corrosion. Remove the socketed IC’s. Check the IC’s and sockets for any corrosion. Replace if necessary. Also check under the solder mask. Corrosion can live under there and you can’t see it. If it looks suspect scrape or sand the solder mask to be sure. You must clean all the corrosion or it will come back. There are several methods for removing corrosion so I won’t get into that here. After a thorough cleaning and inspection you need to replace the battery. There are several methods to replace the battery (NVRAM, remote battery, coin cell, etc.) Again, replace all the headers and crimp connectors. J5 is a 32 or 34 pin connector. I find it easier and not too much more expensive to replace the entire cable. GPE and Weebly Nvram both have replacement cables. Install the board and connect J4 only. Now check TP2 = 11.9 VDC, TP5 = 5 VDC, TP3 = 21.5 VDC.
The lamp driver board is mounted just below the MPU and sometimes it will get corrosion from the MPU above so a close inspection is necessary. After inspection and cleaning, replace all headers and crimp connectors. A faulty SCR will seldom show any damage. But they will show up in the lamp test after the game is all back together.
Next is the sound board. Replace all headers and crimp connectors and look closely at the capacitors. Replace any that show bulging on the top.
Last are the displays. For some reason they are usually really dirty. Remove the connector on the back and slide them out the front. Be careful with the plastic angle bracket holding the glass in place and be careful with the glass. Usually a good cleaning with an air hose and a soft brush is all it takes to clean them up. Then replace the headers and crimp connectors. Some of the connectors get two wires in each connector because they are dazey chained. It’s a little tricky but you can do it. You may have some trouble with some numbers or segments out but those will only show after the game is on and you run through test mode. There is a good article on Pinwiki on repairing displays.
By following these steps you’ve eliminated 90 percent of your problems and will have a good running game for another 30 years.
If you have any suggestions, comments, or tips please add them below.
