Friday, November 26, 2010

Measure eos switches before installing them..

Repaired a burnt flipper coil on a Williams Grand Lizard (system 11).
The EOS switch was broken and the coil had melted a bit internally, the plunger was completely stuck.

Last year I had installed a new flipper coil on my AFM, and after installation I discovered that the coil was bad internally (one of the wires was broken) and the flipper didn't work. Had to remove the coil again and replace with another new coil, a lot of time lost.
Since then I always measure the resistance of each coil before installing it.

Did the same with this game, I measured the new coil to make sure it wasn't broken.
Switched from the old type of sys11 coil to a newer FL-11630, added a yellow capacitor to reduce the arcing so eos-switches don't wear out as much, ..

Everything done, time to test the game.. The flipper worked but went up very slow.
Hmm.. What's wrong here ? Can't be a broken coil as I checked it before installing.

When a flipper goes up very slowly (barely has enough power to go up, but stays in the up position correct), it means it's only working on hold power. So the end-of-stroke switch is not closed or not making good contact.
On SYS11 games the EOS is normally closed, it has to make contact so the flipper has full power, and when opened the flippers have less power (only to stay in the up position).

Measured the brand new eos-switch.. and.. weird ?!
Although the switch blades were adjusted correct and contact points were touching I didn't measure continuity ?! This was a brand new eos-switch, how could it not make contact ?!
It was even exactly the same replacement as the original was, same type, same size and shape, with heavy-duty contact-points.

Luckily I'm well prepared, have about a dozen different switches with me..
Took another type, an universal eos-switch (contact points are the same type but the blade is a bit longer, you can cut/bend it as you wish or add more contact points).

Measured this new eos-switch.. and.. also didn't make contact ? Only after bending the blades so they pushed against each other really good, they started to make contact (and still intermittent).
Used a bit of sandpaper to clean the contact points, and then it worked fine.

Installed this switch in place of the other, and the flipper worked fine. :)

I tested the eos-switch that I had removed; It was a brand new one, looked good, but on the contact points I didn't measure continuity when they touched eachother ?
Maybe they had corroded as I have it already a few years ?! Tried some sandpaper but that didn't help.. first time I notice this :(

Anyway, now I learned to use my dmm to measure each part before installing it, not only coils but also switches, even brand new ones !

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