Archived from groups: rec.games.pinball (
More info?)
"Ken S" wrote:
> In my experience once you get EMs going they are a lot more trouble
> free than newer games. Stepper units need to be lubricated if not
> operating freely but other than that if contacts dirty then just
> playing the machine for a while will usually clean them up.
<snip>
I think it depends on who you ask- some people think (or like to think) that
EM games are more reliable than solid-state games, and vice-versa. It all
depends on the game. I have seen some EM games that have gone for years
without any problems- very reliable. I have seen others that are lucky if
they continue working for over an hour at a time without something breaking
or falling apart. I have seen some EM games that will outlast some
solid-state games. And vice-versa. It all depends.
Personally, I believe EM games are definitely more time consuming to
troubleshoot and repair- even on very minor issues. This, and the high
potential of "return problems" after fixing one of these old-age,
high-mileage, antique machines, are the two main reasons we don't do any
repair work on them in our shop (other than those games that we have
restored/sold ourselves)- they're just too time consuming, and the repair
bills are always high to the customer, and the games usually develop related
or unrelated problems soon after (in many cases) which makes us look bad
since we were the last ones to work on the game. So for these reasons we've
got away from working on them in the past few years. (Same with the
solid-state Gottlieb games, but that's another topic altogether...)
A lot of EM problems/repairs involve tracing through circuits- checking
contacts at each point along the way- until you find the exact wire or
contact point that is causing the problem- one out of the hundreds or
thousands inside the game. Experience counts- being able to "think" in a
way like the machine works, to determine what it's trying to do or needs to
do in a certain procedure, and being able to interpret schematic diagrams
and how they *really* relate to the way the game is actually put
together/assembled/layed-out are tools that will greatly increase your
ability to repair, or decrease the time required to repair, any given
problem. I always tell people that "Fixing the problem is very simple.
It's *finding* the problem that takes all the time, labor, and know-how."
And time is money.
Quick example: We have an old Bally EM pin that we're currently doing a
top-down restoration on- in outstanding shape inside and out- very "low
mileage"- and it had a problem where the flippers and bumpers, etc., would
stay on (active) even when game was over. So naturally you check the
contacts in the game over relay and anything else like that at the "tail
end" of the return line from all the playfield coil circuits. Everything
checked out fine but problem persisted.
So eventually after all the obvious stuff checks out, you have to start
tracing wires and checking for crossed wires/short circuits. Eliminating
portions of the game to try and determine if the fault is in the backbox,
playfield, or mounting board mechanisms. Turns out the return wire from the
playfield coils was shorting out to no less than 6 other wires in the
playfield wiring harnesses. So we start pulling all of those out of the
harness connectors, and replacing, one at a time, until we find the one
that's got the short.
Then start following that wire up the harness and to every switch or device
it goes to on the playfield. And examining each switch/device to make sure
there's no shorts or other problems. And of course watching for "gotchas"
like mashed/pinched wires that are shorted together in the harness, or maybe
a screw that's been run through into a wire or into the harness, or some
other freak of nature.
Eventually we find a switch stack on the front of the zipper flipper
assembly that has one switch leaf on the wrong side of the activating pin,
so when the flippers are open, this leaf gets bent way up and shorts to the
coil return line. Thus causing the problem.
Total time for diagnosing and finding problem by "professional" experienced
pinball techs: Roughly 3-4 hours.
Total time to repair: 10 seconds.
Ray J.
--
Action Pinball & Amusement, LLC
Salt Lake City, Utah USA
Web: www.actionpinball.com
We're serious about pinball. Anything else is just for fun!
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