Post by John RobertsonPost by Lloyd OlsonPost by John RobertsonPost by Larry RosenthalPost by John RobertsonPost by Lloyd OlsonPost by J ManOn Wednesday, March 10, 2021 at 12:21:16 PM UTC-5,
Post by Lloyd OlsonPost by J ManHi- The right flipper on my CFTBL occasionally stays up after
releasing the flipper button. So far, I've replaced the coil,
coil sleeve, the coil stop, spring and EOS switch. I've also
checked and cleaned the flipper button. I've noticed that when
the flipper is stuck up, it will not return down with hand
pressure. When I turn the power off, it falls right back into
place. I could compete a full flipper rebuild by changing the
plunger, link and pawl-but the flipper assembly is moving very
smoothly so I don't think those parts are causing this issue.
Whats next to check? Sound like any specific cause?
thanks!
Swap left and right flipper button opto boards. If the problem
moves to the flipper, then flipper button opto board has an
issue. If not bad diode on coil or a problem on the fliptronics
board.
LTG : )
Thanks- That sounds like a plan. I'll start with switching the
flipper opto boards-I don' think its a diode on the coil since I
already changed one out.
I switched the flipper opto boards and the flipper still
sticks/stays up on the right side. Only thing left is getting the
fliptronics board serviced?
I'd swap left and right flipper coils, just to be sure. Even if
new. New parts can fail, have cold solder joints. Then the
fliptronics board.
LTG : )
I disagree on changing the coils. That won't solve the problem the OP is
having, and just wastes time I'm afraid.
He has determined the problem is on the Fliptronics Board and I agree
with his procedure and assessment. The Hold transistor for the coil is
most likely defective and needs to be replaced.
John :-#)#
I would normally agree with John but the poster said when it sticks
it can't be pulled down by hand. If it were the hold coil he should
be able to pull it down. The odds are it's the hold coil despite
what he said.
I agree the OP wasn't very clear about 'hand pressure' meant in
grams/foot-pounds but if the main coil was stuck on he would have
noticed the smoke soon enough...and probably mentioned it.
John ;-#)#
I agree it's probably on the fliptronics board. LM339 maybe ? Symptom
is the same with a broken diode lead on a flipper coil. Turn game on.
Start a game, push flipper button, it locks on. A transistor issue
would lock on at power up.
LTG : )
Yes, but if the diode was open on the coil it would fry the transistor
and it would never turn off, power off and back on and it would still be
shorted. It might well be the LM339, but Id start with the hold
transistor on the chance it has biasing issues...
One thing the OP could try - start a game, and with the flipper not
energized try lifting the tip of the flipper up. If it pulls and stays
up I would say, pretty safely, that the hold transistor has shorted. In
many cases the hold coil isn't strong enough to lift the flipper, so
this test - without pushing the flipper button - will test that theory.
John :-#)#
John :-#)#
I know this is almost a month old, but I don't understand the concern
about the diode on the coil.
CFTBL is Fliptronics 2. I view D17 through D24 as snubber diodes, and
they would take care of the inductor current (frequently called 'back
EMF') through those diodes, making the diode on the flipper coil
redundant. So if that coil diode breaks, it should not destroy the
TIP102. Or am I wrong on this?
This design is similar to D17 - D32 on the Power Driver Board, which is
why diodes are not required on the 50 V coils.
I am also not sure about the LM339 being a potential problem. But I
guess if it failed to the output to 'on' (low?), then the CPU would read
the flipper as being held 'in' and leave the flipper in the up 'hold'
position? Am I correct on this?
Please help me understand what I am missing. Thanks.
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