wesleycowan;2075512 Wrote:
> On May 22, 9:02*am, Wesley Cowan <wkco... (AT) juno (DOT) com> wrote:
> > The problems I'm having are:
> >
> > 1. *Left ramp periodically goes up and down randomly when it
> shouldn't
> > do that. *I don't see any broken wires or diodes reversed.
> >
> > 2. *Last night a new problem started. *After locking two balls and
> > making a shot it should give a 3 ball multi-ball with the two locked
> > balls and one in the trough. *Instead the third ball was staying in
> > the trough and after awhile it would eject the two locked balls
> giving
> > only a two ball multi ball. *The third ball remains in the trough.
> >
> > I'd appreciate suggestions in searching out fixes for these problems.
> > Thanks!
>
> Just checked by taking each fuse out and all of them test as working.
>
> Did a switch test and 56, 55, 26, and 59 are coming up as errors.
> Wondering if I have a short somewhere?
It can be other things besides a short. Go to switch edge test and
operate the switches by hand first.
If a switch does not work, check these things:
On the top side of the playfield, make sure the bad switch contacts
haven't been bashed together by an errant air pinball.
If it's a micro-switch, check the actuator arm. Make sure it's
adjusted properly. Listen for the micro-switch's "click" when
activating. No click usually means the switch is mis-adjusted or
broken.
Check that the wires going to the switch are soldered well, and
haven't fallen off.
Check the continuity (using your DMM's continuity setting) of the
wire between this switch and another working switch in the same column
(white wire) or row (green wire).
If it's a blade or leaf style switch, check the contacts for proper
closure. Clean the switch contacts with a business card (do NOT use a
file as the contacts are gold plated). Put the card between the
contacts, close the contacts, and pull the card through the contacts.
This is all that is needed to clean gold plated switch contacts.
Check the switch to make sure it works. Use your DMM's continuity
setting, and put one lead on the "common" lug (the lug to which the
banded end of the diode connects) of the switch. Put the other lead on
the green (normally open) switch lug. Your meter should only beep when
the switch is activated, and not beep when the switch is de-activated.
Move the DMM's lead from the green to the white wire (normally closed)
switch lug. Your meter should beep when the switch is de-activated, and
NOT beep when activated.
Check the diode on the switch. Make sure the diode is connected
properly, and is working (see below).
Check other switches in that switch's row or column. Two 4041 chips
control rows, and 2N3904 transistors and 74LS244 at U40 control columns.
Both rows and columns are controlled by a 6821 PIA at U38.
http://techniek.flipperwinkel.nl/wms11/index3.htm
--
wayout440
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