Dragon's Lair joystick wired with capacitors?

Xyla

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Hi,

I have 3 Dragon's Lair control panels and one has ceramic disc capacitors wired up with the joystick directions. I was wondering if anyone has seen this before and what the purpose is. Neither of my other CPs have this.

Thanks.
 
I'm not sure about why they'd be on a Dragon's lair, but in pinball machines they add a capacitor to all of the switches to lengthen the pulse sent to the computer pcb. There's also some on the coin switches of a Pac-man machine. Basically some of the old ic chips on the old boards couldn't 'see' a switch closure if it was really short... so they put a capacitor on it that makes the pulse larger and the chips can see it more regularly. So that's probably what's going on with the pcb in Dragon's lair that handles the inputs.

It may have something to do with 'debouncing' too. If you press a switch, it actually sends like 15 signals to the pcb... all really tiny as the switch makes good contact, loses contact, makes contact again, etc. In pinball machines they code the game so that the pulse has to be at least "......." long or whatever, to ignore if a switch is pressed twice within a tenth of a second or whatever, to get rid of this. Without it, each switch would score like 15 times each time it's pressed once.
 
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Hmmm... that's interesting about the de-bouncing. I guess the question is, is it desirable to have this? Do many people make this modification?

Here's a photo...
 

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Hmmm... that's interesting about the de-bouncing. I guess the question is, is it desirable to have this? Do many people make this modification?

Here's a photo...

I had something like that in a game I bought. It was a conversion tho.
 
I don't see why you'd need it if it didn't come factory, but maybe there was an issue where the gameboard wasn't seeing switch closures good enough.
 
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What are you supposed to please be careful of?
 
Maybe they couldn't figure out why they could not control dirk :) Reminds me of the first dollar I wasted on the game when it first came out. Damn joystick must be broke!
 
I have never seen this on any game, but it makes sence to be found on a game like Dragons Lair. Here it is very critical not to have any bounces or misinterpreted inputs, since the whole game logic is to do one move/choice at every screen.
 
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