Black Knight - I'm Stummped!

eaconner

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My Black Knight has been plagued with issues since I bought it, but it has been fine for the past 6 months or so. Here recently it has been acting up again and I can't figure out whats wrong.

The game runs and plays fine except for one thing, at the start of the first ball it kicks out two balls. The second and third ball only kick out one. I thought it could be a switch error in the ball trough but, as far as I can tell all of the switches are working properly.

Any ideas?
 
This may sound like a stupid question, but how many balls are in the machine?

There should be only 3. If there are more, it would get confused. Strange that it only happens on the first ball. Are all the boards original?

I have an issue with mine (for another thread) that I can't figure out either.It's a switch issue but I have replacement RottenDog boards in mine.

Chris
 
On mine, i've had to adjust and mess with the leaf switch in the upper multi-ball channel.
seems like it takes a beating and gets tweaked due to that nylon nub that sticks up.

when that leaf switch is funky it causes odd kick out behavior in the shooter channel.
 
On mine, i've had to adjust and mess with the leaf switch in the upper multi-ball channel.
seems like it takes a beating and gets tweaked due to that nylon nub that sticks up.

when that leaf switch is funky it causes odd kick out behavior in the shooter channel.

I didn't even think of checking those switches. I'll give them a look-over tonight. They really do take a beating.
 
I didn't even think of checking those switches. I'll give them a look-over tonight. They really do take a beating.

Definitely worth a look but if the game is kicking out extra balls in the lower trough because there are stuck switches in the upper trough they did a pretty poor job writing the code ;)
 
Ha! I don't know anything about the code but weird stuff happens when that upper switch isn't happy. and depending on where it thinks balls are sitting in storage between the 3 locations, the ball kicks out down below during play.

logically you'd think the ball sensor isn't in tolerance down there. but if it's consistently only happening at start. dunno. on mine, when i got it the right bolt wasn't in that hanger so the skirt was floppy on the right side. sometimes the ball would try to kick out and it'd fall back repeatedly so the thing would keep kicking.
i added a bolt and tightened up the metal skirt. that seemed to take whatever bounce was happening out.

had similar thing with upper multi ball. had to put actual nuts on the plastic because the ball was hitting the metal skid plate and bouncing itself back into hole repeatedly.
put the nuts on, it tightened up the skid plate so ball slipped out efficiently.
no problems since. knock on wood.
 
Definitely worth a look but if the game is kicking out extra balls in the lower trough because there are stuck switches in the upper trough they did a pretty poor job writing the code ;)

Spent a lot of time in the code and it's a pretty complex section.

Don't have it all compiled yet, but basically if it senses three balls between the lower and upper trough's, and nothing in the shooter lane, it tries to kick one out into the shooter lane. It does factor in if balls are in the #1 slots in those trough's, but not much else. Then layer on top of that the multiball sequences for 2 and three ball plus the bonus ball for multiplayer games, I'd assume you probably see some strange stuff in 2-ball multiball as well?

Realistically though they came up against limitations in the available space. Black Knight, believe it or not, uses every single bit of the 6k on the game ROM chips with none to spare. The biggest chunks are dedicated to the drop target coding, followed by the ball storage code for the multiple troughs and such. There's a reason you didn't see many early solid state games with multiball, until the later board generations that had a lot more available ROM space on them. Just look at the kludgy Firepower ROM map that it took to fit that multiball code into a board that was probably never intended to use all those EPROM slots at once.

Compare this to games like Gorgar and Flash that use not much more than 1k of code on the game ROM. All on a single 2716, and probably half that is empty.

-Hans
 
Spent a lot of time in the code and it's a pretty complex section.

Don't have it all compiled yet, but basically if it senses three balls between the lower and upper trough's, and nothing in the shooter lane, it tries to kick one out into the shooter lane. It does factor in if balls are in the #1 slots in those trough's, but not much else. Then layer on top of that the multiball sequences for 2 and three ball plus the bonus ball for multiplayer games, I'd assume you probably see some strange stuff in 2-ball multiball as well?

Realistically though they came up against limitations in the available space. Black Knight, believe it or not, uses every single bit of the 6k on the game ROM chips with none to spare. The biggest chunks are dedicated to the drop target coding, followed by the ball storage code for the multiple troughs and such. There's a reason you didn't see many early solid state games with multiball, until the later board generations that had a lot more available ROM space on them. Just look at the kludgy Firepower ROM map that it took to fit that multiball code into a board that was probably never intended to use all those EPROM slots at once.

Compare this to games like Gorgar and Flash that use not much more than 1k of code on the game ROM. All on a single 2716, and probably half that is empty.

-Hans

Interesting. So they DID do a crappy job with the code ;) Crappy being relative because they were extremely limited by space and actually did an amazing job with the code. The code space was jammed not only by multi-ball routines but increasingly complicated game code, light shows, audits, etc... There are a lot of differences between Flash and Black Knight beyond multi-ball.

In any case, if there's a switch stuck you'll see it in the switch test.

I think another big part of the jump to multi-ball was just being brave enough to do it. Bally could have added more ROM space than Williams System 7 has to their -35 in 1978 if they wanted to using the exact board they were already using and either a daughter board connected to the expansion header or some basic hacks on their existing MPU. That's what Pinstar did for Gamatron. Technically speaking any manufacturer could have done that in the early solid state era with a small CPU socket based daughter board. They either hadn't thought of it or were not brave enough to do it.
 
I think another big part of the jump to multi-ball was just being brave enough to do it. Bally could have added more ROM space than Williams System 7 has to their -35 in 1978 if they wanted to using the exact board they were already using and either a daughter board connected to the expansion header or some basic hacks on their existing MPU. That's what Pinstar did for Gamatron. Technically speaking any manufacturer could have done that in the early solid state era with a small CPU socket based daughter board. They either hadn't thought of it or were not brave enough to do it.

Not sure why, but Williams sure got stuck on the concept of backward compatibility with their board designs early-on and that hampered them a lot as well. I think they really dropped the ball on System 7 in a lot of ways by not addressing the existing problems with the split board setup. It's not until System 9 or 11 that I really consider their board designs to be matured sufficiently. Everything prior had some kind of kludgy design elements in it.

You could see the software side improvements as early as Black Knight, when Larry Demars came on board and they finally stopped building everything with an EM influenced layout that just happened to have fancy sounds and edgy artwork. They badly needed a dedicated code guy to keep up with Steve Ritchies game concepts, and then a hardware guy to keep up with the combo of Larry and Steve.

Good old Williams, they remind me a lot of Land Rover. Take some pure awesome, mix with a dollop of WTF, and throw it in an oven set on "random".

-Hans
 
Not sure why, but Williams sure got stuck on the concept of backward compatibility with their board designs early-on and that hampered them a lot as well. I think they really dropped the ball on System 7 in a lot of ways by not addressing the existing problems with the split board setup. It's not until System 9 or 11 that I really consider their board designs to be matured sufficiently. Everything prior had some kind of kludgy design elements in it.

You could see the software side improvements as early as Black Knight, when Larry Demars came on board and they finally stopped building everything with an EM influenced layout that just happened to have fancy sounds and edgy artwork. They badly needed a dedicated code guy to keep up with Steve Ritchies game concepts, and then a hardware guy to keep up with the combo of Larry and Steve.

Good old Williams, they remind me a lot of Land Rover. Take some pure awesome, mix with a dollop of WTF, and throw it in an oven set on "random".

-Hans

There's only one word needed to make the early solid state Williams stuff look like genius. Gottlieb! hehe

I would say that Williams moved out of the EM like era with Flash. Then Eugene Jarvis went to Williams and did Firepower with Steve Ritchie. That was pretty innovative too. Don't forget that Larry and Eugene were the "Vid Kids" responsible for programming arcade games like Stargate and Robotron. Amazing programmers.

Williams always had a more "operating system" like approach to their software design. Ultimately, that proved to be the right strategy.

As far as backward compatibility goes I think you have to look at it in terms of cost. It's not so much backward compatibility but working with what you've already got and not having to spend a ton of money designing, testing and implementing something new. It's hard to say if they hung on too long. They made a shit-ton of money on the system 7 games I'm sure so it's hard to say they did. You could say though that they should have skipped system 9 all together. Now, Gottlieb system 80B... that's a case for hanging on too long to old hardware ;)
 
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