Leaderboard

Just had a board in from a Match it machine that was listed as dead and on test it just sat there looking at me. First thing to check is the 5v and this was spot on. Next point of call is the main clock which wasn't running. Most times if not all is the 9602 (8602) chip that's failed. These are also used in the MPU3 but for a different purpose. These are getting very scarce these days, which I've mentioned before, and the prices on Ebay are ridiculous. Once replaced the board burst into life and ran all the diags and played games OK. After a good soak test it was time to pack it up and send it back. Back in the users machine all was not good. There were problems with payouts and the Match it feature didn't work. Not too long after the board died again. Most faults I've come across with payouts are due to the reel sensor backplane board but the main worry was the board being dead again. This time the board came back with the backplane and the sensors. Back on the bench with the board again I quickly discovered that although it looked like everything was ticking over ie all address and data busses were running there was no enables going to the PIO chips. IC7 (74LS02) had failed, you couldn't make it up! Because of this I decided to swap out all the small TTL chips just in case. They all tested OK but I didn't want to get bitten with another failure. Moving on to the backplane there were two outputs not being switched and this was due to the CD4049. All sensors appeared to be OK using my sensor tester so it was time to return. A longer soak test was carried out and all looked good. I had to do some detective work on the slingshot mech to get a good understanding of how it functioned and to work out how I could check the payouts on my test rig. Once I was happy back it went. Back in the machine it was functioning again but wouldn't run the Match it feature on reel 1. Also the Gamble feature never did what it said on the reel? Lots of head scratching then began to try and diagnose what was occuring and why. The first thing that became apparent was the lamp on the reel backplane interface board wasn't lighting up and this was due to one of its legs was broken. This never left the machine as it's bolted to the reel deck. That would explain the Gamble reel. Next conumdrum was the Match it issue. From the symptoms shown on various videos I assumed it had to be something to do with reel 1 not being sensed correctly. Lots of avenues were tried to no avail and I was running out of ideas. One other possible reason was the green interface cable between the deck and MPU. Sometimes you get dry solder joints on the plug (socket). This was checked and continuity tested but all looked good. Photos were sent over and no solder rings were able to be seen although it is very difficult to see them sometimes in pics. A breakthrough came at 04:00 this morning when the owner checked the continuity again and found that two connections, although showing good between the pins at each end, had no connection to their pads! A quick job with the iron and the Match it feature was back on. To say I was relieved was an understatement and the owner was ecstatic. Well you would be wouldn't you.