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Black Heart
Joined: Oct 01, 2017 Posts: 7 Location: San Francisco
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Posted: Sun Oct 01, 2017 3:12 pm Post subject:
Troubleshooting a Klee |
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I have a few problems with the Klee I just put together. 1: Load glitches, some steps turn on that shouldn't & weak LEDs. 2: No CV out at all. The 3 TL074CN & the CD4051BE in the analog section are hot. 3: Bus 1 & 3 have no output. bus 2 works fine. I did find a missing 2 pin header, J13 in the digital section and added it. I think that some chips were damaged because that power jumper was missing. Any help would be appreciated. |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Mon Oct 02, 2017 4:34 pm Post subject:
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Anything being hot is a sign that there's a short or near short somewhere.
Power off
Use a meter to verify whether there is a short between +V and ground, +V and -V, and -V and group.
if there is, pull all the chips and see if the short persists.
If it does, you need to check your solders for possible shorts. Also pull the PCBs apart and remove any cables and see if it persists.
If not, you have a bad chip, you'll need to put them back in one at a time until you reproduce the short, then you'll know what's bad. |
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Black Heart
Joined: Oct 01, 2017 Posts: 7 Location: San Francisco
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Posted: Mon Oct 02, 2017 6:52 pm Post subject:
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Thanks for the response. I figured there's a short. Any clue about the load glitches. That one is a bit odd. The bus problem I can probably figure out but I'll listen to any suggestions. I have the newer version where the analog & digital sections are on one board. |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Mon Oct 02, 2017 6:58 pm Post subject:
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One thing at a time. Attack the most obvious problem first, it may be related in some subtle way to the less obvious ones. |
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Black Heart
Joined: Oct 01, 2017 Posts: 7 Location: San Francisco
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Posted: Mon Oct 02, 2017 7:00 pm Post subject:
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You're right. I ordered a bunch of parts already. Won't be able to work on it till Sunday. |
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Black Heart
Joined: Oct 01, 2017 Posts: 7 Location: San Francisco
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Posted: Fri Oct 06, 2017 8:13 pm Post subject:
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Ok I think I found the ground fault. The pots are shorted. I don't have the energy to take the face plate off again tonight. That took hours to find. |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Fri Oct 06, 2017 9:34 pm Post subject:
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But there's always the good feeling of knowing what the problem is. At least for the next iteration.... |
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Black Heart
Joined: Oct 01, 2017 Posts: 7 Location: San Francisco
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Posted: Sun Oct 08, 2017 6:08 pm Post subject:
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I can't seem to find any shorts in the analog section. Voltages to the chips are right. The chips a warm, not hot. Maybe nothing wrong with the power there. I had a cold solder joint at glide A pot. Can you tell me what signals I should expect at J4 or analog section U6, etc? I jumped W2 and I did get a pulse at the output that followed the clock, but no volt changes. Removed the jumper. I'm beginning to think the problem is in the digital district or a connection. Any info on what signals should be at certain test points would be appreciated. I'm really getting to know this circuit. Been poking at it and staring at the schematics for hours. Thankx. |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Sun Oct 08, 2017 7:00 pm Post subject:
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If you have a Muffwiggler account, there's a Euro Klee thread there that would likely get you better answers. I don't currently have a built Klee (two in various states, but not finished) to be able to get you voltages. |
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Black Heart
Joined: Oct 01, 2017 Posts: 7 Location: San Francisco
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Posted: Tue Oct 10, 2017 5:30 pm Post subject:
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Ok, thankx. Does this sound familiar? Turning on a step switch also turns on the LED to the left of it. Only happening in section A. Strange problem. |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Tue Oct 10, 2017 5:49 pm Post subject:
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No, sorry. I'd suspect the cable wiring, just because that seems to cause the most weird behavior, but that's a total SWAG.
Except of course, there aren't cables in this version.... |
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Black Heart
Joined: Oct 01, 2017 Posts: 7 Location: San Francisco
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Posted: Sat Oct 21, 2017 10:37 pm Post subject:
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I fixed the Klee sequencer! Everything was pointing to the counter shift registers. I replaced both CD4034BE chips. Everything works. I had some problems with the crappy wire that came with the partial kit, for the pots. I'll finish putting it back together tomorrow. |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Sun Oct 22, 2017 9:21 pm Post subject:
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Cool! Good job! |
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