uO_c 8hp ornament and crime.

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!

Moderators: lisa, luketeaford, Kent, Joe.

Post Reply
moogah
Wiggling with Experience
Posts: 443
Joined: Mon Nov 22, 2010 10:27 am

Post by moogah » Sat Mar 30, 2019 1:48 pm

Hopefully someone can point out what (probably) obvious mistake I've made here. Built one with pre-soldered smt parts yesterday, but it doesn't seem to want to wake up. The screen doesn't turn on and the little led on the teensy just blinks (it'll stop blinking and go solid if I click the button.. I don't know anything about teensy so no idea what this means.)

What did I forget to do?

Image

Image

User avatar
degeneratedsines
Common Wiggler
Posts: 156
Joined: Thu Dec 28, 2017 1:03 pm

Post by degeneratedsines » Sat Mar 30, 2019 3:30 pm

did you upload the .hex program to the teensy with usb cable and teensy loader application ?

moogah
Wiggling with Experience
Posts: 443
Joined: Mon Nov 22, 2010 10:27 am

Post by moogah » Sat Mar 30, 2019 4:35 pm

You mean did I RTFM? Obviously I didn't.

Sorry for wasting bandwidth..

User avatar
SphericalSound
Common Wiggler
Posts: 183
Joined: Thu Feb 01, 2018 9:23 am
Location: Spain

Post by SphericalSound » Sun Mar 31, 2019 6:48 pm

patrickod wrote:hey folks,

I'm building my first uO_C and managed to get a working powered-up module complete last night. On first run through everything works *except* the right encoder "switch" button functionality. The encoder increment/decrement input works however, and the joints don't show up any obvious issues under visual inspection.

I've reflowed the encoder pins, C33 to which the switch ground pin is connected, and the corresponding header and teensy pins to no avail. I have a spare encoder which I can substitute in later this evening but was wondering if anyone had hit this issue in their own build where something else was at fault? I'm unsure how likely the encoder is to be half broken in this way, or whether it's a red herring.
You can do a continuity test before replacing it. It will show you if the encoder button is working or not

User avatar
SphericalSound
Common Wiggler
Posts: 183
Joined: Thu Feb 01, 2018 9:23 am
Location: Spain

Post by SphericalSound » Sun Mar 31, 2019 6:49 pm

aragorn23 wrote:Hi all,

I've managed to build one uO_C successfully, but my second attempt seems to have an issue: it switches on and everything appears to work but when I calibrate I just get a steady voltage of around 2.4v from each CV out channel regardless of the calibration settings.

Anyone else ever experience this problem or know what the likely culprit is? I did reflow the DAC already.
I had the same issue as you but with 8v3 volts everywhere. I fixed it with flux and hot air in the DAC.

You could check the voltage reference as well and the OPAS. Just reflow all them

User avatar
patrickod
Learning to Wiggle
Posts: 20
Joined: Sun Dec 30, 2018 3:18 pm
Location: San Francisco
Contact:

Post by patrickod » Sun Mar 31, 2019 7:13 pm

I made a bunch of progress on my build in the last two days. The encoder issue turned out to be somewhat of a red herring as in fact during the process of having to unsolder the teensy headers on the PCB due to a misfit I broken several of the traces. In total I needed to supplement 4 broken traces with wires to get the Teensy fully connected.

With that done the final holdout issue is a broken CV1 input. During calibration CV2-4 display nominal jitter values around the 0 mark, however CV1 varies wildly with deviations in the hundreds. I've reflowed the components on the CV1 path, and have confirmed that each of the CV inputs on the teensy pins are around the 2.2V mark.

At this point I'm beginning to think that I've somehow damaged the ADC on the Teensy itself, as I can't point to anything substantially different between the broken CV1 input and the remaining three.

User avatar
patrickod
Learning to Wiggle
Posts: 20
Joined: Sun Dec 30, 2018 3:18 pm
Location: San Francisco
Contact:

Post by patrickod » Sun Mar 31, 2019 9:45 pm

I just now discovered the debug menu. Here's the ADC output.

Image

CV2-4 look stable enough, though CV2 appears to have some jitter bleeding from CV1. I've reflowed The 75k resistors R34, R38, R26, R30 but that didn't make any noticeable change.

User avatar
patrickod
Learning to Wiggle
Posts: 20
Joined: Sun Dec 30, 2018 3:18 pm
Location: San Francisco
Contact:

Post by patrickod » Tue Apr 02, 2019 1:16 am

Spent a bit more time debugging this evening but still no luck. I temporarily removed R25 to rule in/out either side of the circuit but saw the same jitter on CV1 leading me to suspect that I've somehow damaged a trace on the Teensy itself.

Just to be sure I removed the screen and to reflow the header pins on that side of the board which were previously inaccessible, and again the same result persists.

Not being familiar with the Teensy and its SOC is it likely that this single ADC input is hosed while the remaining three have survived? Or should I look at bridging the SOC ADC input directly to the header to double check?

User avatar
charonme
Wiggling with Experience
Posts: 314
Joined: Tue Mar 11, 2014 3:35 am
Location: BA, Slovakia (EU)

Post by charonme » Thu Apr 04, 2019 10:08 am

which encoders should I get? the one mentioned in the 8hp BOM is unavailable.
Is this one (24steps with switch) ok? (from the original BOM)
Last edited by charonme on Thu Apr 04, 2019 11:36 pm, edited 1 time in total.
spotify, bandcamp
Heptaphasis - DIY 3HP 7-phase quadrature sine LFO

DJ_JITTER
Learning to Wiggle
Posts: 22
Joined: Thu Aug 16, 2018 1:38 pm

Post by DJ_JITTER » Thu Apr 04, 2019 11:45 am

Hello folks, is anyone (preferably EU based) currently selling any PCBs for this? Everywhere I've looked is out of stock.

User avatar
patrickod
Learning to Wiggle
Posts: 20
Joined: Sun Dec 30, 2018 3:18 pm
Location: San Francisco
Contact:

Post by patrickod » Tue Apr 09, 2019 12:13 am

charonme wrote:which encoders should I get? the one mentioned in the 8hp BOM is unavailable.
Is this one (24steps with switch) ok? (from the original BOM)
AFAIK they'll work, but one thing to note is that they're knurled shafts in case you have D shaft knobs to use with them. If so 652-PEC11R-4120F-S18 I think is the closest alternative. The only difference that I can spot between it and the original is that it is 18 pulses per rotation as opposed to 20.

User avatar
charonme
Wiggling with Experience
Posts: 314
Joined: Tue Mar 11, 2014 3:35 am
Location: BA, Slovakia (EU)

Post by charonme » Sun Apr 14, 2019 4:08 am

degeneratedsines wrote:Also how difficult would it be to do a clean fix for the teensy power on this rev:
Image
I seem to have the same pcb, I don't know which version this is. Will I have problems with the power issue that the "power supervisor" is supposed to solve on the other pcb version?

I don't see the MIC803 (U12) power supervisor chip in the BOM here https://github.com/jakplugg/uO_c

There is also a U11 on the schematic, but not on the BOM and my pcb doesn't have a footprint for U11 or U12. What is U11?
spotify, bandcamp
Heptaphasis - DIY 3HP 7-phase quadrature sine LFO

User avatar
mxmxmx
Super Deluxe Wiggler
Posts: 2242
Joined: Thu May 31, 2012 1:54 am
Location: berlin

Post by mxmxmx » Sun Apr 14, 2019 6:20 am

charonme wrote:Will I have problems with the power issue that the "power supervisor" is supposed to solve on the other pcb version?
probably not. the MIC803 thing helps solve a problem *if* there is a problem, ... the manifestation of which really depends on the specifics of your PSU (basically, how fast the various power rails come up). in my experience the MK20 chip (= teensy 3.2) is fairly robust in this connection (unlike K66 = teensy 3.6, which IIRC was how the supervisor thing got started in the first place. (even K66 should be somewhat more forgiving by now / as of the latest "teensyduino" release, see here)). in case you do have problems with start-up, the supervisor circuit is pretty simple, you'll probably be able to improvise something using the outer side pins resp. bottom side pads.

re "U11" -- that would be the OLED, i think.



@patrickod: have you figured CV1 out by now?

User avatar
charonme
Wiggling with Experience
Posts: 314
Joined: Tue Mar 11, 2014 3:35 am
Location: BA, Slovakia (EU)

Post by charonme » Sun Apr 14, 2019 5:26 pm

mxmxmx wrote:re "U11" -- that would be the OLED, i think.
ah yes correct, sorry, it is in the BOM on the second sheet
spotify, bandcamp
Heptaphasis - DIY 3HP 7-phase quadrature sine LFO

User avatar
patrickod
Learning to Wiggle
Posts: 20
Joined: Sun Dec 30, 2018 3:18 pm
Location: San Francisco
Contact:

Post by patrickod » Mon Apr 22, 2019 2:30 pm

mxmxmx wrote:@patrickod: have you figured CV1 out by now?
Unfortunately not. I just last week purchased an oscilloscope finally which I'm sure will help tracking this down, though I'm not yet very familiar with! I'm guessing that I should see the same jitter if I probe the ADC input pin? They each should measure a steady ~2.2V right?

User avatar
mxmxmx
Super Deluxe Wiggler
Posts: 2242
Joined: Thu May 31, 2012 1:54 am
Location: berlin

Post by mxmxmx » Wed Apr 24, 2019 1:25 am

patrickod wrote:
mxmxmx wrote:@patrickod: have you figured CV1 out by now?
Unfortunately not. I just last week purchased an oscilloscope finally which I'm sure will help tracking this down, though I'm not yet very familiar with! I'm guessing that I should see the same jitter if I probe the ADC input pin? They each should measure a steady ~2.2V right?
yep, the pins in question should all sit at ~2.2V. i don't have a good theory re what might be going on, i'm afraid ...

i don't think it's likely that the ADC as such is damaged (all those pins, ie #17-20, are muxed to the same ADC module (ADC0)), so i'd figure they'd all be off in that case. CV2-CV4 look ok though (judging from the picture further upthread); CV1 is a bit hard to discern (i'm assuming that's after calibration?). so the right column says 27xx ? and the left one 4xx?

when you patch in a signal, can you see those values move along?
did you double-check R25 ? (should 100R, not 100k)

User avatar
EvanLang
Learning to Wiggle
Posts: 12
Joined: Wed Apr 10, 2019 12:13 am
Location: Denver, CO

Post by EvanLang » Thu Apr 25, 2019 12:45 pm

Is the pogo pin reset suppose to be depressed all the time and soldered to the pcb, or free moving kind of like a reset button?

moogah
Wiggling with Experience
Posts: 443
Joined: Mon Nov 22, 2010 10:27 am

Post by moogah » Thu Apr 25, 2019 9:10 pm

EvanLang wrote:Is the pogo pin reset suppose to be depressed all the time and soldered to the pcb, or free moving kind of like a reset button?
The pogo is spring loaded so you can push the teensy down on it before solding the teensy into place. This makes sure the pogo is always putting pressure on the contact. I soldered in the pogo first, then soldered in a couple pins of the teensy while pushing down on it so the pogos spring was compressed. Make sense?

User avatar
mxmxmx
Super Deluxe Wiggler
Posts: 2242
Joined: Thu May 31, 2012 1:54 am
Location: berlin

Post by mxmxmx » Fri Apr 26, 2019 2:25 am

moogah wrote:
EvanLang wrote:Is the pogo pin reset suppose to be depressed all the time and soldered to the pcb, or free moving kind of like a reset button?
The pogo is spring loaded so you can push the teensy down on it before solding the teensy into place. This makes sure the pogo is always putting pressure on the contact. I soldered in the pogo first, then soldered in a couple pins of the teensy while pushing down on it so the pogos spring was compressed. Make sense?
yep, it has to make contact with the "RST" pin in order to work.

fwiw, i personally wouldn't use those short pogo pins, and wouldn't solder the dev board directly onto the PCB, for that matter. it won't be fun if for some reason you have to, or want to, replace the teensy.

there's longer pogo pins which will work with sockets/headers, like these:

Image

(PGTH1250 would be the part #, IIRC, though the diameter of those might be too large, ... don't know / haven't tried):

User avatar
mxmxmx
Super Deluxe Wiggler
Posts: 2242
Joined: Thu May 31, 2012 1:54 am
Location: berlin

Post by mxmxmx » Fri Apr 26, 2019 2:27 am

...double

User avatar
EvanLang
Learning to Wiggle
Posts: 12
Joined: Wed Apr 10, 2019 12:13 am
Location: Denver, CO

Post by EvanLang » Fri Apr 26, 2019 9:42 am

moogah wrote:
EvanLang wrote:Is the pogo pin reset suppose to be depressed all the time and soldered to the pcb, or free moving kind of like a reset button?
The pogo is spring loaded so you can push the teensy down on it before solding the teensy into place. This makes sure the pogo is always putting pressure on the contact. I soldered in the pogo first, then soldered in a couple pins of the teensy while pushing down on it so the pogos spring was compressed. Make sense?
Makes total sense. Thank you.

User avatar
charonme
Wiggling with Experience
Posts: 314
Joined: Tue Mar 11, 2014 3:35 am
Location: BA, Slovakia (EU)

Post by charonme » Sat Apr 27, 2019 3:58 am

this display fits perfectly https://www.ebay.ie/itm/263339864243 but it came broken :(
Image

btw where should I look for some test points? I found the 3.3v from adp150 (U7), 5v from LM1117-5 (IC6) and -5v from LM4040 (U6)
Some other test points are mentioned here: https://c1.staticflickr.com/1/321/32002 ... 6747_h.jpg

also I assume the display will get the 3.3v only after the teensy is connected?
spotify, bandcamp
Heptaphasis - DIY 3HP 7-phase quadrature sine LFO

User avatar
mxmxmx
Super Deluxe Wiggler
Posts: 2242
Joined: Thu May 31, 2012 1:54 am
Location: berlin

Post by mxmxmx » Sun Apr 28, 2019 4:02 am

charonme wrote:
also I assume the display will get the 3.3v only after the teensy is connected?
correct.

re test points, if you get 5V from the LM1117-5 and 3.3V from the ADP150 that'll probably do unless you have reasons to suspect something is off

User avatar
patrickod
Learning to Wiggle
Posts: 20
Joined: Sun Dec 30, 2018 3:18 pm
Location: San Francisco
Contact:

Post by patrickod » Thu May 02, 2019 2:09 am

mxmxmx wrote:
patrickod wrote:
mxmxmx wrote:@patrickod: have you figured CV1 out by now?
Unfortunately not. I just last week purchased an oscilloscope finally which I'm sure will help tracking this down, though I'm not yet very familiar with! I'm guessing that I should see the same jitter if I probe the ADC input pin? They each should measure a steady ~2.2V right?
yep, the pins in question should all sit at ~2.2V. i don't have a good theory re what might be going on, i'm afraid ...

i don't think it's likely that the ADC as such is damaged (all those pins, ie #17-20, are muxed to the same ADC module (ADC0)), so i'd figure they'd all be off in that case. CV2-CV4 look ok though (judging from the picture further upthread); CV1 is a bit hard to discern (i'm assuming that's after calibration?). so the right column says 27xx ? and the left one 4xx?

when you patch in a signal, can you see those values move along?
did you double-check R25 ? (should 100R, not 100k)
Unfortunately still no success after another round of debugging. I double checked the resistor values against the other working three inputs and replaced a capacitor that looked out of place, replaced the MCP6002, and removed R25 completely but each time the same ~400 jitter persists on CV1. Patching an input to it also doesn't have any effect. The search continues!

User avatar
mxmxmx
Super Deluxe Wiggler
Posts: 2242
Joined: Thu May 31, 2012 1:54 am
Location: berlin

Post by mxmxmx » Thu May 02, 2019 11:28 pm

patrickod wrote: [...] and removed R25 completely but each time the same ~400 jitter persists on CV1. Patching an input to it also doesn't have any effect. The search continues!
no effect? -- so that's re CV1? or CV1-CV4? if you patch a LFO or the like, have you checked the signal arrives at the pin?

Post Reply

Return to “Music Tech DIY”