DISCO FEVER PINBALL



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My boards arrived back from Scott, or should I say, a CPU board and a driver board arrived, not the same ones that left, but a CPU board and a driver board nonetheless, and I was eager to get them straight in my machine and fire it up, but there was a little work to do first. Scott had replaced my System3 CPU board with a System 6 CPU board, easily discernible immediately by the different placing of the battery holders on the board. This isnít really an issue but you might recall that I mentioned one of the first things you should do when repairing a machine of this type is to move the batteries of the board completely and house them somewhere else in the backbox because the batteries can leak corrosive material over the CPU and driver board. Not only that but the corrosive fumes from the batteries can also corrode the ROM sockets and the 40 pin connector strip between the boards. This damage is not always obvious so itís a good idea to just do this modification anyway and put them elsewhere in the back box and simply run wires back to the original connectors.

That done I fitted both boards and crossed my fingers as I powered the machine on. Once a few seconds had passed I began to breathe again, but only slowly, as I was fully expecting to smell the burning metal or melting plastic any second, but luckily it didnít come. The machine had booted cleanly and none of the coils had locked on, the machine had reset completely.

It seemed like a good idea to insert a coin and play a game then, so thatís just what I did, albeit a very limited game due in no small part to my utter incompetence at playing pinball but also due to that fact that some of the playfield items were not working as intended. More important than that though, it was a very quiet game because I did not yet have a working sound board so Iíd not connected to the driver board and it wasnít powered.

For now though, I was more concerned with the physical aspects of the game, some of which werenít quite working as planned, most importantly of all both of the flippers were quite weak, one of them in particular, the left one, was so weak that it could barely lift when the ball was on it so something was clearly not right. Bear in mind that about half of all Disco Fever machines (including mine) have curved flippers which are heavier than normal flippers, so I changed them for a pair of lighter, straight flippers to see how much of a difference that made, but with the left one it wasnít much.


Flippers problems arenít normally very difficult to diagnose and the cause can be found fairly simply by looking at the symptoms.

If the flippers don't work at all then it is almost certainly a blown fuse, either fuse F4 on the power supply board or on earlier games a flipper fuse under the playfield. Once the fuses are checked then you can test for voltage at the flipper coil, if there is none at all then you need to start looking at the connectors on the driver board that drive the flippers, check for broken wires and check the connector that links the back box to the playfield.

If you have power getting to the flipper coils but the flippers still wonít fire then you should check the ground wires from the flippers to the playfield to make sure that you have a good grounding. Assuming youíve already tested the coils and resistance much earlier then the coils themselves should still be sound.

If the flippers work but "flutter" and donít stay up when the flipper button is held then usually the hold winding on the coil itself is broken. The hold winding is the thin wire that makes up the coil and if it is broken you can usually see it broken away from one of the coil solder lugs. It could also be that the EOS (End Of Stroke) switch is not adjusted properly.

If both flippers work but are equally weak then the most likely suspect is the bridge rectifier as it runs both flippers, but if only one flipper is weak then that points to one of two things, either mechanical binding caused by mal-adjustment of the mechanism or once again the EOS switches.

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