Hmmmm, Time clean your playfield weekly???
The age old problem of the ball 'bringing' carbon-dust from the underside ball-lanes up onto the playfield and rubbers etc.
I've read all kinds of thoughts & theories about the old 'black powder'.
It can be reduced by having good clean switch contacts on all the solenoid EOS positions etc (flippers, kickers, bumpers).
Dirty (resistive) switch contacts (and partial/worn contacts) will tend to arc far more than clean new switches.
This is really only a problem on the HiVoltage/HiCurrent switches, which are usually always EOS switches in flippers & bumpers etc.
I considered installing some form of catchment around each of the switch contacts, something like a small material 'bag' so the dust settles into the fibre, instead of tipping out of a plastic scoop when you lift the playfield.
My other concept was to MOVE the switching contacts down into the furthest part of the cabinet, preferably inside a contained box, there's no reason that the switches need to be right next to the solenoids, other than "it's handy to wire them there", and there aren't really "that many" EOS-type switches to move elsewhere.
You could probably just mount them in a handy box that sits in the coinbox tray, so you could empty/vacuum the container with ease simply thru the coindoor opening.
My other concept was to install an Electrostatic precipitator(ESP), a High Voltage device that would sit inside the cabinet and attract all the carbon dust into it, instead of letting it float around the underside ramps and playfield etc.
Various types of ESP's are used in Aircon ducts and hospitals to filter the air as the dust pases thru and is captured on the hi-Voltage plates...."High Voltage" being around 10kv to 20kv at very low current.
In fact the Horizontal Output transformer from an old monitor will do this fine.
(which is also why old TV's have a pile of dust around the EHT/HV Aquadag plug on the rear of the tube).
Hope this kinda helps anyone out there???
MM
