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 Forum index » DIY Hardware and Software » Klee sequencer
Just got a Klee! Two issues, I think
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thresholdpeople



Joined: Jul 17, 2014
Posts: 19
Location: NYC

PostPosted: Thu Jul 24, 2014 8:35 pm    Post subject: Reply with quote  Mark this post and the followings unread

I just popped the new rotary switch in, and same thing.


Edit: No I take it back. I think that's just a ground plane..

Back to prodding around.

___

The traces from pin 3 and pin 6 run right never to each other from the rotary to the female headers. There doesn't seem to be any visible damage to the traces. Can it be a pcb defect?
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elmegil



Joined: Mar 20, 2012
Posts: 1524
Location: Chicago
Audio files: 14

PostPosted: Thu Jul 24, 2014 8:48 pm    Post subject: Reply with quote  Mark this post and the followings unread

Measure at the switch then.

The common should be +V all the time. Pos 1 should not be hooked to anything, but should go positive when you're at the first position. Then positions 2 - 8 in turn as you rotate the switch. At each step, none of the other positions should be high.

At that point if you're not going from 000 to 111 on pins 11 10 & 9 on the 4051, then you have a problem somewhere along the way from the three pull down resistors (R46, 47, 4Cool, the diodes (D1-12) to the chip.

if you suspect the chip, you could pull it out and measure whether the three pin positions are correct without it there (I'm assuming it's socketed, if not, that check would be a last resort).

Is it possible that some of D1-D12 are backwards??
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thresholdpeople



Joined: Jul 17, 2014
Posts: 19
Location: NYC

PostPosted: Thu Jul 24, 2014 9:16 pm    Post subject: Reply with quote  Mark this post and the followings unread

I'm getting this short even before the other boards are attached. Where ever it is, it's on the fader and switch board.

Here are some links to photos I've taken of the pcb. Not sure that they actually help with anything, but mostly documentation that the pcb looks fine...

[img]https://secure.flickr.com/photos/borisklompus/14552334928[/img]
[img]https://secure.flickr.com/photos/borisklompus/14552534887[/img]
[img]https://secure.flickr.com/photos/borisklompus/14552533997[/img]
[img]https://secure.flickr.com/photos/borisklompus/14736623794[/img]

Thanks again for your help. I really appreciate you taking the time, and you've helped me suss out a lot of these problems and are guiding me toward a resolution. Thank you!
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elmegil



Joined: Mar 20, 2012
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Location: Chicago
Audio files: 14

PostPosted: Thu Jul 24, 2014 9:57 pm    Post subject: Reply with quote  Mark this post and the followings unread

You're quite welcome. A lot of folks around here (and on Muff's) have helped me, I like to do what I can to give back. Plus I really like troubleshooting, even though sometimes it makes me nuts Smile.

I'm not sure what you mean about "this short" -- are you saying pin 3 and pin 6 are shorted together?

This is the datasheet for the rotary: http://www.taiwanalpha.com/english/p_e_141.htm

Pins 1 & 10 are the common, pins 3 & 6 correspond to positions 2 & 5 respectively. And yeah, if they were shorted before the diodes, that would look like either 2 or 5 was the same address as 6.

At the connectors to the other boards, pin 3 goes to the "outside" header, middle position, and pin6 goes to "inside" header, middle position.

I honestly don't see *any* very likely position for them to be shorted though. I suppose that if you worked really hard at it you could short them at those headers, but that seems really unlikely.
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thresholdpeople



Joined: Jul 17, 2014
Posts: 19
Location: NYC

PostPosted: Fri Jul 25, 2014 6:22 am    Post subject: Reply with quote  Mark this post and the followings unread

Right, exactly. My pictures followed the traces from when the pins of the rotary go through the PCB until they reach the headpins. I can't see any obvious place for them to short together along that path.

I've tried reflowing the solder at the header pins, but that's unlikely. I applied very little heat to the rotary, but it could be a freak coincidence that the same malfunction happened, but it isn't likely.

elmegil wrote:
Pins 1 & 10 are the common, pins 3 & 6 correspond to positions 2 & 5 respectively. And yeah, if they were shorted before the diodes, that would look like either 2 or 5 was the same address as 6.


Why would it look like the same address as 6?
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elmegil



Joined: Mar 20, 2012
Posts: 1524
Location: Chicago
Audio files: 14

PostPosted: Fri Jul 25, 2014 7:52 am    Post subject: Reply with quote  Mark this post and the followings unread

position 2 connects to the top address line, and position 5 connects to the bottom address line. Position 6 connects to both.

position 2 is binary 001 (2 - 1 = 1), position 5 is binary 100 (5 - 1 = 4), position 6 is binary 101 (6 - 1 = 5), and 001 + 100 = 101


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Screen shot 2014-07-25 at Jul 25 9.47.15AM.png


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thresholdpeople



Joined: Jul 17, 2014
Posts: 19
Location: NYC

PostPosted: Fri Jul 25, 2014 8:04 am    Post subject: Reply with quote  Mark this post and the followings unread

Ahh.. Right.

Ok. Will be combing over the board again.
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thresholdpeople



Joined: Jul 17, 2014
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Location: NYC

PostPosted: Fri Aug 01, 2014 12:55 pm    Post subject: Reply with quote  Mark this post and the followings unread

Well, I've tried looking for shorts, but I haven't found any. I took the rotary switch off again, and the short is still there. I can't figure out where it can be, even teeny bits of solder slag shouldn't short the two positions together, as the contacts are never that close to each other.

I'm just going to live with it and tune position 6 in a way that makes the most sense to me.

Thanks again for your help and time elmegil!
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elmegil



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Audio files: 14

PostPosted: Fri Aug 01, 2014 7:09 pm    Post subject: Reply with quote  Mark this post and the followings unread

You're quite welcome.
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