What makes a flipper 'bounce'

[Wotto]

Scenario

* Flipper is being held up in gameplay.
* Ball rolls down playfield towards the flipper , the tip end.
* You continue to hold the flipper button in / flipper stays up.
* Ball contacts flipper tip and the flipper mechanichally moves down a few mm and jerks back to UP position.
* Ball flys back to general playfield area.

I should know this by now 

[pinnies4me]

Dodgy/poorly gaped EOS

[ddstoys]

+1 for the EOS switch or even check the coil stop if it's badly worn it may not hold the plunger as well as it should

[robm]

Just had this problem, and it turns out the plunger was worn down about 3mm or so, presumably there was not enough 'plunger' or coil force due to lack of length ot hold the flipper up - it momentarily drops down, then re-energizes.

So a new plunger fixed mine, but coil be a coil stop as well.

With WPC machines, i was led to believe that the EOS was pretty much redundant - i remember reading on pinrepair that if the flipper button is pressed and held, and the EOS is not closed in a certain number of milliseconds, then the fliptronics board drops the coil to low power to eliminate molten coil disease...or am i wrong?

[Strangeways]

Nearly always an adjustment in the SS machines. Could be a lose wire on one of the EOS blades. If the flipper has full power (the ball moves fine in normal play), but the flipper drops when the ball hits it - then t will be EOS.

While the flipper button is pressed, and the flipper makes a humming noise, or "chatters" then it could be a worn plunger or mushromed coil stop. The coil stop could also be magnetised.

A simple test.

Start a game and press the "good" flipper button. Push down on the flipper itself. Should be a fair amount of resistance and then a "hum" as you push harder, before it drops, and then returns very quickly to the UP position.

Compare with the "floppy" flipper. If it drops without much resistance, then it should be an EOS problem. Clean and gap the same as the strong flipper and report back. The coil will become WARM if the EOS is not closing, then the coil will hove no power, then the scoil sleeve will melt.

It could also be the diode across the secondary "hold" winding. But I doubt it.

Which machine are we talking about ?