(Topic ID: 221631)

Black Knight weak lower flippers and resetting


By jcar302

1 year ago



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  • 17 posts
  • 5 Pinsiders participating
  • Latest reply 1 year ago by Pin-up
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#1 1 year ago

Hey guys, picked up a pretty nice black knight.
Didn't work, but turns out, the coin door connector was shifted one pin to the right causing the coin door switch (the one that knows if it's closed) to put the game in diagnostics mode.

Next up, the lower flippers just dont' feel right.
All flippers appear to be completely rebuilt with new parts, except one has an older coil.
Adjusted the eos's no notable change.
The uppers seem strong, but it's such a small area it's hard to tell.
Cross referenced the coils with the ones marco sells for them (out of stock) and the numbers match.
No capacitors on the lower coils, should there be?
Every flipper measures 38v

Game has a rottendog mpu.

I checked for the "mushrooming" people seem to discuss for the coil stops, didn't see any.

The other thing is the top left flipper coil buzzes pretty badly sometimes, other times less but it's always there.
No bind in any of the components and parts are tight and work smooth. RESOLVED SEE BELOW

Any insight would help.
Thanks,
Joe

Edit:
There is always a chance that i'm expecting too much from the lower flippers. This is the only game older than space shuttle I've owner to date.
The left ramp is possible, it just takes a precise shot.

#2 1 year ago

Make sure to replace the male and female connectors at 3J3 on the power supply board. Also, I'd re-pin the ground connectors for the flippers at 2J12 (i think that's the one, it's on the driver board in any case--check the manual to be sure). Also, were the cabinet flipper switches replaced? I'm assuming the eos switches have been replaced, but if not, I'd go ahead and install new ones.

#3 1 year ago

Buzzing flippers are usually the coil stops. If your plates have the coil stops that screw on loosen the screws and mess with the stop.

#4 1 year ago

Thanks guys.
I planned on taking a good look at the power supply. I'll go through the connectors.
It likely needs a rebuild, but since this game is a birthday gift for my father, I need it to be as reliable as possible so I don't have to do any repairs at his house later.
I was considering just switching to a rottendog power supply and putting the original in the box with the original mpu that came with it.
If it was staying at my house i'd just buy a rebuild kit.

As for the coil stops, I took that coil apart and everything looked right, I also activated it with the screws loose and it didn't really seem to change much.
Later today i'll take it apart again and take some pics. I've read that these stops get damaged and the entire assembly needs replacing and i'd be curious if these parts are original.

#5 1 year ago
Quoted from Travish:

Buzzing flippers are usually the coil stops. If your plates have the coil stops that screw on loosen the screws and mess with the stop.

So on your advice I messed with the flippers some more.
Turns out when someone did all four flipper rebuilds, one came with a difference plastic piece in the middle (not sure what's called). 3 were shaped like a V so the spring didn't pile up.
One was shaped like a U and caused the spring to bind.
I could tell because all the other flippers slapped when drawn in.
Took it out, tapered it for now with a grinder and the buzz is gone.
Thanks.

The flippers switches seem ok, but I think i'll get a new pair.

Another problem that I was hoping was random, but i'm starting to think isn't, is that sometimes the game just ends in the middle of a ball.
Power supply problem?
I ordered a rebuild kit instead of the rotten dog.
I'll check all connectors and reflow at the same time.

#6 1 year ago

Does the game end completely mid-game, or just the ball in play? Does it appear to be tilting?

Or perhaps the game's resetting (could be low 5v or something mpu related, if that's the case).

#7 1 year ago

keeping an eye on this thread. I've rebuilt my lower flippers on black knight, new coils and all, and they have always been weak. I think I remember something about a possible miss wiring of the lower flipper coils from the factory back in the day that would cause them to be weaker? Just as your machine is, it will barely get the ball up the ramps to the upper play field.

Had this issue with my Truck Stop as well, but then read that the balls should not be the typical standard size ball and replaced them with the proper size balls as per the manual, and I could hit everything. Truck Stop was the same where I had rebuild the flippers completely and the ramps were still hard to hit.

I did try those smaller balls in the Black Knight, even though they aren't supposed to be in there, and it always had trouble reading that they were there when the ball drained or at the top where you lock the balls for multi ball. So, don't bother trying the smaller balls to adjust for the weak flippers!

#8 1 year ago
Quoted from frunch:

Does the game end completely mid-game, or just the ball in play? Does it appear to be tilting?
Or perhaps the game's resetting (could be low 5v or something mpu related, if that's the case).

Game just stops completely, score gone and displays go back to defaults.
I can push start immediately and start a new game.

I thought it could be a 5v problem, part of the reason i'm going to rebuild and reflow the power supply.

#9 1 year ago
Quoted from jcar302:

Game just stops completely, score gone and displays go back to defaults.
I can push start immediately and start a new game.
I thought it could be a 5v problem, part of the reason i'm going to rebuild and reflow the power supply.

That's where I'd start, for sure. Hopefully new caps, connectors, etc will get you all fixed up. Good luck!

#10 1 year ago
Quoted from jcar302:

Game just stops completely, score gone and displays go back to defaults.
I can push start immediately and start a new game.

You might want to tilt the game with the slam, ball and plum bob and see if it acts the same. Then you will know its not a switch matrix problem. Either way, not usually a big problem. I had a slam tilt problem on a Firepower and went in the wrong direction for a while chasing a reset.

#11 1 year ago

Received my rebuild kit today (arcadepartsandrepair.com).
Didn't get a chance to do the rebuild, maybe when the kids goto sleep tonight.
But I removed the power supply and on the top of the board there is a 15 pin connector with one blank.
Not sure what it goes to since I don't have the manual yet, but pins 1,2,3,12,13,14,15 are clearly cold solder joints. Some look like I could pull the pins out.
What's does the connector control?
Also the top left silver cap (vertical) looks expanded.
So hopefully remedying these things will help.

20180725_185111 (resized).jpg
#12 1 year ago

Looks like you *may* have found the culprit, then. It looks like that's connector 3J6, which provides 5vdc and ground for the mpu and driver boards. Definitely reflow or replace the headers and female connector for that one...and also replace the headers and female connector at 3J3 while you're at it to hopefully give your flippers a bit more oomph...

Good luck!

#13 1 year ago

Well, so far so good, no resets as of right now.
Installed the cap kit, went pretty easy.
Changed out a few headers, that didn't go so easy. I'm used to capping monitors and figured with my fr300 those pins would slide right out, but they were a pita to get out and back in, the holes need to be really clean.

The connections in the pics above were really bad, so bad when I pulled the connector off most of those pins pulled out quite a bit.

The flippers feel a little bit better, but i'm starting to think I may be expecting too much from 28v flippers and the long shot up the left ramp.

I'm going to do new female connectors, but my molex crimping tool didn't get here yet. So that will be in a few days.

Thanks,
Joe

#14 1 year ago

Nice! Hopefully changing out some of the female connectors will help out a bit too. Definitely replace and/or properly gap the EOS switches so they open later in the stroke if you haven't already. Also make sure to replace the cab switches if they haven't been replaced. The current goes through the eos and flipper switches, so bad/pitted contacts will definitely affect flipper strength. At very least, you should be able to make the ramp ok, even if it doesn't blast all the way up.

Keep us posted!

#15 1 year ago
Quoted from frunch:

Nice! Hopefully changing out some of the female connectors will help out a bit too. Definitely replace and/or properly gap the EOS switches so they open later in the stroke if you haven't already. Also make sure to replace the cab switches if they haven't been replaced. The current goes through the eos and flipper switches, so bad/pitted contacts will definitely affect flipper strength. At very least, you should be able to make the ramp ok, even if it doesn't blast all the way up.
Keep us posted!

Was digging through some parts looking for something today and found a matching double flipper switch new (who the hell knows what I bought it for originally) and clearly they haven't changed the design in years since it was a perfect match from marcos.

I'd say it made the right flipper even better.
Any good shot goes up the left ramp.

In conclusion, i'm going to have to say it's a combination of parts that make for good flippers on a system 7 or older.
The power supply, connectors, headers, flipper mechanicals and the switches.
Thanks for the help.
Joe

#16 1 year ago

Awesome! Glad you got it all sorted out. Nothing like blasting a shot up the left ramp with the spinner lit. That sound!

BK is a great game, enjoy it!

#17 1 year ago

I'm going to have to have a look at my flipper switches. I may have overlooked those when I rebuilt the flipper mechanics originally.

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