Fashionably late to the party

In Portland it is hard to get to parties on time.."Oh yeah I had stuff to do guys are still going right?" After all- how can you get to parties when there's so much mustache preening/fixie riding/food cart patronizing to do? There's only so much time to do these things in between liberal arts college and graduate school! But, I digress...

I have had various stops and starts with this with my ambitious off-board wiring scenario, v.1.0 pcb and finally started populating it into a recovered Commodore 64 enclosure with a replacement panel in ABS. Arcade buttons etc. It's been a challenge. I have it almost all boxed up except I broke a trace that connects to pad 3 (right most pad) of the "fine" tune knob. Kind of a bummer as I haven't figured out how best to jump the goof yet.

Well I started this back when I knew less about what I was doing so it has all kinds of kludgy wiring joints and such. I can't remember how to insert images in this forum


  • edited July 2011
  • How do you insert pics? I have one I'd like to share.
  • @psazmatron: just copy+paste the URL of the pic itself, that's all.

    looks good from here ;)
    good idea to use an old C64 case for the party. i hope you'll post some pics of the completed sampler too.
    and one thing's sure, you're not the last one to even start a new WTPA1 ;-)
  • I hope to finish it this weekend - my boss told me to take Friday off :)
  • edited July 2011
    Finished! I broke more wiring while constructing this into the case, but it works. The only issue now: shortly into final testing I stopped getting overdubbing and stopped being able to go into granular mode. I could not find an electrical issue and realized that I can make these happen only if I press the shit out of S1. So I will need a replacement arcade button for that. What's a bummer about that is it makes me wonder what the overall life span and reliability of those are (the ones sparkfun carry.) I was hoping to build a midi controller that uses them. Anyone have any experience with those relatively long term, positive or negative?
  • My guess would be it's not the button, but perhaps a connection. Most arcade buttons are made pretty well to take abuse.
  • That's what I thought, so I resoldered connections on it and checked for breaks. The button gives me functionality if I apply a lot of pressure, which is why I think it's the button and not a joint that's at issue.

  • it could always be that a microswitch has gone bad, like other things too. i've never had problems with mine though. have you soldered the cables directly to the switches? if you used connectors you could easily swap 2 microswitches and see if the problem moves to another function.
  • @rosch - what do you mean by microswitches? my wiring goes directly from the pcb to the lugs on the arcade buttons...

    strangely the button has also become more reliable with lots of if it had not been broken in (???) I did some touch up soldering but could not tell if that helped. Strangely, now the issue isn't initiating overdubbing, its just that once overdubbing is activated, it won't stop!

  • edited July 2011
    i meant something like that (not exactly, this one's to operate another switch nearby, but they look very similar). of course your buttons could have entirely different operating. the ones i have all match those (so called) microswitches. but they're kinda deep, too...

    doesn't it also stop overdubbing when you hit eg the play key?
  • wow, that's what is inside the arcade button? interesting!

    Yes I can deactivate overdubbing by hitting S2 or S3.

  • edited July 2011
    actually that's a switch that's clamped behind the button, while only a plastic part protrudes and operates the switch.
    mine look like in that pic:

    hm, so it seems to be the switch.
    do you have a spare one that you could connect with croco clamps to the suspect's lugs, just to try?

    edit: or maybe you could try and see if it works when you momentarily bridge the button's lugs with a wire, if that works it's definitely the button, or the soldering on the lugs, but nothing on the board

    edit again: doh! now i've seen the back side of your buttons! they're way flatter than mine. were they expensive?
  • edited July 2011
    these are convex arcade buttons from sparkfun, not cheap but not so bad.

    so I may have determined the problem. today I noticed strange behavior from more buttons. I opened up my WTPA and firmly pressed each latch chip into its socket. there was the slightest clicking sound and then I put it back together on power up - I got the best functionality from all the buttons. Pretty much perfect, although you really have to wack the button very firmly to get action.

    I have a Deluxe Memory Man which has a chronic problem of the BBD chip slowly slipping out of its socket. I do not know whta causes this. Heat? Moving the item around a little bit physically?

  • Sockets often cause problems over time. Make sure they are very securely seated, and also that no pins are bent (this is easy to do, and also easy to miss). Likewise, you can test your switches by shorting the switch leads. Should act as a switch closure although it may bounce.
  • the atari st's are notorious for the chips coming "unsocketed". There is this thing us vintage computer nerds call the "atari drop" where you pick the damn thing up off the desk and drop it and it reseats all the chips. I had a really old (82/83) and mint atari 520 st that was behaving really badly. I was disappointed that it wasn't working correctly, but then remembered the drop, dropped it back on my desk and tada! it works perfectly!
  • Sorry to resurrect an ancient thread but some months into rocking the party I really think these cheaper end Sparkfun switches may not be ideal, in case anyone else was using those. Talked to a friend who does professional synth electronics and also runs our local vintage arcade, Ground Kontrol. He suggested sourcing "real" arcade buttons. They won't be incredibly cheap, but their performance should be uniform.

    they look more like rosch's switches- they have proper microswitches as part of the assembly, unlike my Sparkfun brand.

    If anyone else has experience with the Sparkfun brand I could compare to that would be great...

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