This is a Bally/Stern 101 Test Fixture by Universal Module Company. I had never seen or heard of one of these until a few weeks ago when a buddy of mine who obtained this from an operator’s warehouse sent me a picture and asked if I was interested. I very much was!
This test fixture was made by Universal Amusement Distributors in Huntington Valley, Pa. in the early 1980’s or late 1970’s. Since I have been in the hobby for over 15 years now and have never seen or heard of it, nor are there any pictures or documentation on this fixture in the test fixture Pinwiki page, I imagine that there were not a lot of these made or sold.
It’s an amazing little piece of test equipment though! Since the architecture for Bally 17/35 and Stern Model 100/200 games are nearly identical, it works for both board sets. It has on board LED displays which allow you to test the MPU’s digitry outputs for all displays including the match/credit display. It even goes up to six player select for games like Six Million Dollar man! With all boards hooked up, you could theoretically simulate an entire game.
In addition to booting a full 7 flash for the MPU and simulating its operational status, it also will individually test the lamp driver board chips and SCRs, Solenoid Driver voltage outputs and transistors, sound board outputs (there is a little speaker in the back), and individual six digit display functionality. What’s even more impressive is that this entire unit is very light and not much bigger than your hand!
Thankfully, all of the harnesses were there and in tact which made taking this in a lot more reasonable. Without them, I’m not sure how easy it would have been to reconstruct. When I got this in it kind of worked for some things, but not for others. The on board LEDs didn’t work at all and the display functions only strobed the 1’s digit select. The lamp driver functions worked, I didn’t bother testing the solenoid driver before digging in on the other issues.
Before doing anything, I rebuilt the power section. My guess is this hadn’t been in service for 20-30+ years. The last of the Bally 17/35 and Stern Model 100/200 games rolled off the line around 1984. Stable power on any electronic device is always priority one, otherwise you are potentially chasing your tail with everything else. Once that was rebuilt I dug into the on board LED display circuitry. It turned out a bad 4049 hex inverting buffer chip was what was hanging that up. For the digit selects on the display test, I had to probe back through almost that entire circuit to find a missing clock signal on a 74LS161N that led back to a bad 555 timer.
After those repairs, I put it through the entire run of tests and it passed all of them well to the manual. The green side LED is slightly dim on the 190v LED that I’ll hit if I have to open it up again, but that’s really nit picky as it still works fine functionally.
I’m very happy to have this tester in my stock and with how versatile and compact it is, I’ll likely consider letting my Bally Brown Box Four set go to save some precious space in the shop. A huge thanks to John Robertson of Flippers.com/John’s Jukes for providing me with documentation including an operating manual and schematics that helped me save this unit. The only thing available online was one news release PDF that was a few pages, so his help in securing those documents was a life saver.
The original unit came with a switch matrix strobe board, but it was long missing on mine. Thankfully, Andrew with NVRAM.weebly.com sells a Bally/Stern switch matrix board which was a perfect drop in for my missing original. All I have to do is ground pin 1 of J3 on the MPU and it’ll run me through test mode and allow me to test the matrix or make changes on the on board adjustment menu if there is one for a particular title.
