DigDug V2 (UPDATE: Works great!)

[neiloler]

Hi gents and gens, here's my DigDug pedal. It's working...sort of...

I seem to be getting nothing but random. I'm going to pull out the potentiometer board (uhg) and check wiring there, but anyone have any ideas of a quick thing to check before I tear this thing down to the ground?

Here's some pictures:

EDIT: I did use a CD4017BE instead of a CD4017... am I hosed?

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[gtr2]

bump, cause it looks sweet...sorry I can't help u out

[maysink]

Maybe desolder the random stomp switch and make sure no solder bridges exist. You getting any barely-audible high-pitch clock noise in bypass?

At any rate it looks good!

[neiloler]

Nope, I'm not getting any clock bleed, though it does seem like the LEDs are proportionately bright to the position of the knobs associated with the LED.

Is this normal? I've never seen/used the ZVex version, I'm not sure what "right" looks like.

I'm thinking it's time to remove the pots board. 

[maysink]

yeah, the 8 step leds increase in brightness as you crank their respective pot.s double check for solder bridges where the random switch meets the pcb.

good news on the clock noise--I think I got that on mine 'cause I insisted on putting it in a too small enclosure.

[neiloler]

Maybe the clock bleed was just proximity to the actual chip? I would have thought it was just because it was noisy in itself. Not sure.

I checked the switch for solder bridges, but I'm still not finding what I know should be there. I'm going to check the actual board tomorrow, there's got to be something I'm not seeing.

Fresh pair of eyes and all that.

G'night.

[madbean]

This is the exact chip I used in my build, and the one that's used in the YouTube demo
http://www.youtube.com/watch?v=s-xgjIMSVMs

NTE4017B:
http://www.mouser.com/ProductDetail/NTE/NTE4017B/?qs=sGAEpiMZZMsagl7BRmp5TRbi3B9%2FYpOoxPub0kBmB2A%3D
http://www.alliedelec.com/search/productdetail.aspx?SKU=9358084

Datasheet: http://www.alliedelec.com/Images/Products/Datasheets/BM/NTE_ELECTRONICS/935-8084.PDF

The one you used should be fine...the "E" designation is for package type, I believe, which in our case is a PDIP-16

If you are only getting the 'random' mode then my first thoughts are: something has gone wrong with the 'random' switch wiring, or you've used an incorrect value for C13 (which pretty much sets the amount of randomness). You may need to pull it out and test it without the switches (this is what I do before boxing anything up).

Also:

One customer mentioned that the Vactrol listed in the Dig Dug might not be the best choice (VTL5C3). A VTL5C9 may be a better choice, and I actually have one on the way to test out.

Looking at the datasheet (p.46): http://www.datasheetcatalog.org/datasheet/perkinelmer/VT500.pdf it looks like the differences between the 5C3 and 5C9 correspond to dark resistance, temperature coefficient, speed response and light history. Honestly, I don't know much about Vactrols, so I'll do some reading and investigating and see if this might relate to the problem of 'bunching' up on the sweep of the pots.

I know that the 5C9 is used with the probe designs, so it may very well be the one needed here.

[neiloler]

Very cool Brian, I'd love to hear back on the 5C9. I'm guessing you get a bit of the bunching up on the pots then?

I'll do some tweaking this weekend.

[neiloler]

So I pulled it out of the enclosure, checked all the wiring of the pots, checked both boards for solder bridges, and the value of c13. All was fine. I can't figure out for the life of me why this isn't working. I'm using 2n5088 transistors, should I be using BS170s instead? Could that be throwing it off somehow?

[madbean]

Yeah, you need to use the transistors listed. Subbing a bi-polar for a mosfet generally is not going work.

[neiloler]

Yikes. This would probably be a really funny time to mention I'm in college for electrical engineering. Haha. Thanks, I guess I was thinking they were interchangeable for some random reason. I'll swap 'em out and report back.

[gtr2]

good luck, I'd like to see some closer pics when it's finished too!

[neiloler]

It now works as far as the logic goes, but it's dead quiet when engaged. Oh brother. I'm diving back into it right now.

[neiloler]

I'm still seeing some bunching up on the brightness of the LEDs and range of the effect, so perhaps I'll try the 5C9, but it works.

The strange thing is that I had to reverse the BS170 in Q1 to get it to work correctly... not sure what the heck is going on with that one, but hey, it works.

Thanks for the help peeps, I really appreciate it, especially you Brian for helping me get this thing off the ground at all by your beautiful PCB design work.

[Melonhead]

hey neil your enclosure looks pretty sweet.   did you just buy a pre-powder coated enclosure and use water slide decal paper for your "Dig Dug man"  graphic?.

i also noticed you chose to side mount the "4-6-8" step switch instead of using the template'd top mount.   what's up?  just wondering because im getting ready to source out parts for this build. thanks man.