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Restoration Bally Roller Derby 1960

It was quite a while that we restored a bingo from the very beginning of the OK era.
The recent years we did  the ever popular Silver Sails, Bounty and Golden Gates,
and therefore we wanted to do something different now. From our extensive stock
OK machines we chose a Roller Derby. A good playable bingo, which we know the
scores and features will come up easy and even the feature "two in blue" often is lit.
That last is not factory error, but indeed designed by Bally in that way.
The Roller Derby has a simple artwork and it is easy to get the correct colors. But to
get the exact structure in the paint appeared to be a head ache

This time no comprehensive report with a lot of pictures, but I opted for a report in the form of a film that can be seen via Youtube.
Of course we also encounter problems during a restoration and  I'll try to highlight the causes and solutions found.
It turned out that the Roller had known some technical problems in the past. The Spotting index was replaced by a Timer index. These indexes seem to be alike, but a Timer index only needs to stop a fiber disk, while the Spotting Index works has to stop an iron sprocket. So the used index was worn completely and  a new Timer Index Unit made by  Coos like new again, was fitted.
Again in this bingo a lubricant was used which remained as a thick layer on the axes of the Mixer and Control units and stuck on the leather clutches. Moreover parts of theThe axles were rusty and all clutches were worn out and had tob e replaced.
All kinds of additional tilt systems were mounted, not only in the cabinet, but also in the head. All the extra wiring was removed, so that the original wiring could be followed through the schematics.
We always replace the fusehousing. The original holder wasn't even bad, but we know from experience that difficulties are avoided by replacing it.

The Magic Screen feature unit had been in the fire, the reset coil was replaced by a too large coil, so the holders were bent open and the wiring was restored in a foul way. From an old parts machine a replacement unit was mounted.
The Replay Register was very dirty and after dismantling the unit, the reset coil turned out to be bunrt out and there was a crack in one of the numbered wheels. Furthermore, some components have a lot of wear and tear. So the counter had to be  completely replaced.
The ball-lift motor was very noisy and had to be replaced.
After cleaning everything  and the new components were fitted, the Roller Derby was  sprayed in the original colors and the bingo was ready for testing.

But there were still a few problems:
It turned out that every now and then the lights of the Magic Screen did not work, but also sometimes there was no power supply of the Search Relais. Most of the times the cause of this problem is in the Jones Plug, but these are always thoroughly polished. It was something else. Some contacts of the playfield weree heavely corroded. After polishing all the contacts with the Dremel, a few lights remained to give problems. Not all the time, but after some time it revealed that one of the fingers  in the Magic Screen Unit Disc caused the trouble. During the cleaning session this finger was slightly bent and did not have enough pressure everywhere.
Pressing the yellow button after playing the fifth ball, the two lamps of Extra did not burn sometimes. The Extra Ball trip relais worked well and all contacts were clean and had plenty of pressure. The cause turned out to be a switch in the Red Button relay. The SPDT switch turned out to have dirt or not enough pressure.
Tenslotte vonden we dat het relais van mixer 2 irritant bromde en dat één van de switch van dat relais niet meer 100% was. Dus werd de unit door een nieuwe vervangen en was het brommen weg, alles werkte weer zoals het hoorde.
After adjusting this switch a new problem came up. If a new game was started and the first ball was shot, the shutter closed the playfield and at that time there was another start pulse. Again the Red Button Relay  turned out to be responsible.
When working on this relay it turned out that a switchblade made contact too long. Just a good adjustment
did solve this strange problem.
So we tried and played along and everything went fine. Suddenly the bingo did not start an OK game anymore
and the # 29 relais never came in. Strange, the Roller Derby had done all OK games flawlessly till now. It took
even some investigation but then it appeared that one of the fingers of the Search Unit was bent slightly.

Finally, we found that the relay of mixer 2 was rather noisy and that one of the switches of that relay was not
longer 100%. So the unit was replaced by a new and the irritating humming was disappeared, everything worked
again as it should be.

See also the YouTube movie