Bumper Switch Williams

[Flyte]

Confused by this bumper switch for Black Knight - SW-11a-35

Bought the switch from Pinball Center which is http://www.pinball.center/en/shop/electronics-parts/switches/2436/bumper-switch-williams-sw-11a-35

It doesn't have any side ties for the diodes

The same part number on Marco has the side ties in the diagram but not on the main picture: http://www.marcospecialties.com/pinball-parts/SW-11A-35

Do I need the Diodes does anyone know?

Here's a picture of the new and old side by side

Anyone have any ideas?

 

[chris b]

Yes you will need the diode

 

[Flyte]

can it loop onto the same tie as the cables? there's 6 lugs in the old switch and only 4 in the new one...

 

[Nedreud]

Carefully take apart the old leaf switch and lay out the parts in the order they were assembled. I think you may find the side tabs are electrically isolated from the long contact leaves and are just used as a mounting point for the components and cables. I could be totally wrong but I've had this on switches in my games. Hopefully you'll be able to re-use the side tabs in your new switch. Just take a few photos before you start so you know how it went together and which colour wire went to which tab.

 

[replicas]

Why not just source the correct replacement part.
Much easier.

 

[Jay Walker]

Flyte,

Just in case you weren't aware, the Jet Bumper switches on older Williams games are actually two separate switches.

The part nearest the 'spoon' blade, with the Orange/trace and Black wires, connects directly to some gating logic on the driver board, and switches the coil driver transistors without referring to the cpu board. The capacitor and 100 Ohm resistor improve the sensitivity of the switch. Their junction needs a 'dead' lug in the block of leaves and insulators.

The second part, operated by the fibre linkage of the bumper, is a regular 'matrix' switch, and requires an isolating diode, again with a dead lug.

As replicas points out, the switch as supplied isn't suitable. What's the actual problem, btw? Neither part carries a high current, hence their having gold contacts. Usually, cleaning and adjustment improves bumper operation. Though Black Knight, and to a greater degree the designers' later F-14, don't have a great deal of 'stuff' around the bumper to provide rebounds.