Hawkeye

LoopA V2 Introduction, Features & Support Thread

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Here is the "minimum system" with +5V in red, 0V in blue. Also PA11/PA12 as before. Try pulling off the diode too!

 

5ef7acbbc0f09_LoopA_USB_5V-0V.PNG.8e96f9

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Posted (edited)

Maybe stupid but... A faulty usb cable? The one you use with LoopA is necessarily different from the one you use directly with the waveshare, so...
On sait jamais ;)

Edited by Antichambre

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Just now, Antichambre said:

Maybe stupid but... A faulty usb cable? The one you use with LoopA is necessarily different from the one you use directly with the waveshare, so...
On sait jamais ;)

tried 3 different ones

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Posted (edited)

Just now, Altitude said:

tried 3 different ones

Obviously ;)

Anyway, this problem is fascinating to follow, what a suspense, we can not wait to discover the outcome ;)
I hope it's not too much frustrating for you!

Edited by Antichambre

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Posted (edited)

Solved!

And this is some crazy ass shit too: I was friction fitting the core with the mainboard to see if removing the TVS fixed it (it didnt) so the plan was to try the temporary headers like andy suggested with the minimal setup but my trimmed down, solder coated ones were not fitting the sockets i had so I decided just to put new headers on the core, not a big deal, suck out the solder and pull the pins out one at a time.  When I did the first row and pulled off the plastic header there was a fair amount of solder where the plastic was (like it puddled there).  I just ignored it thinking it was from the desolder gun and cleaned it all up but after the clean up, and new headers, it fired right up.  In hindsight, there was way more solder there than should have been, I was sucking out solder through one end and pulling the pin out through the other, what was left there after I removed the plastic was in the shape of the plastic header like a mold, there is no way that came from the desolder gun especially since it sucks solder out or from any other soldering I did since those were on the other side of the header.  I checked all the IO pins for shorts to ground and +5 but NOT to each other which seems to be what was happening here, must have happened in the wave machine when those headers were soldered on at the factory. Just dumb luck i decided to replace those, I would have never found it otherwise, should have taken a picture

 

Edited by Altitude
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This has to be reported to the Waveshare team for their QC.

IMG_1929.JPG?raw=1

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7 hours ago, Altitude said:

Solved!

And this is some crazy ass shit too: I was friction fitting the core with the mainboard to see if removing the TVS fixed it (it didnt) so the plan was to try the temporary headers like andy suggested with the minimal setup but my trimmed down, solder coated ones were not fitting the sockets i had so I decided just to put new headers on the core, not a big deal, suck out the solder and pull the pins out one at a time.  When I did the first row and pulled off the plastic header there was a fair amount of solder where the plastic was (like it puddled there).  I just ignored it thinking it was from the desolder gun and cleaned it all up but after the clean up, and new headers, it fired right up.  In hindsight, there was way more solder there than should have been, I was sucking out solder through one end and pulling the pin out through the other, what was left there after I removed the plastic was in the shape of the plastic header like a mold, there is no way that came from the desolder gun especially since it sucks solder out or from any other soldering I did since those were on the other side of the header.  I checked all the IO pins for shorts to ground and +5 but NOT to each other which seems to be what was happening here, must have happened in the wave machine when those headers were soldered on at the factory. Just dumb luck i decided to replace those, I would have never found it otherwise, should have taken a picture

 

 

Wow, what a saga! I'm really sorry that you had to go through all of that. I'll discuss with Peter as to how we can compensate you for the trouble. It's the first time we've seen something like this and of course it will be reported to the manufacturer. Seems like fab errors crop up from time to time but it always sucks to get stumped by them.

Well done again for sleuthing it out. Hope the rest of the build goes better.

Best,
Andy

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Posted (edited)

no compensation needed. I know how these things go.

I wish I could have found the actual spot where it was shorting, it definitely wasn't a board problem since I did inspect the underside pins after I cleaned it off  and it worked with the new header so that only leaves the solder bridge and that fits the symptoms.   Checking for shorts to adjacent I/O pins would have identified the issue, might be worthwhile to spot check a couple in inventory to make sure it was just a fluke and not a batch thing.

anyway, that's that.  

IMG_20200629_084743a.jpg

Edited by Altitude

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any 10 pin female header that style will work, the height on that one wont matter

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Posted (edited)

ok when height dont matter than this is the only replacement at the moment: (2,54mm, 2Row, 10 Pins, Female, Thruhole, without cutting a more pinned header...)

https://www.mouser.at/ProductDetail/3M-Electronic-Solutions-Division/929975-01-05?qs=bX1%252BNvsK%2FBrGbqaIqQvrfA%3D%3D

i phone mouser now.... to change my order... want to start solder ;) not to wait.

EDIT: mouser munich - nice - ok will get it soon ;)

thx

Edited by Phatline

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Your proposed part substitution should work.

Check the interboard spacing:
16mm M2 spacer
3M FF header socket 8.26mm
TE thru-board header 6.5mm
14.76mm, you have >1mm to spare.

FWIW I've used large strips of FF sockets for years, just cut down with a dremel-like tool and you lose that position as the tool "melts through". But it works fine and is cheaper than individual sockets of the right size.

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Hey all, I've gotten most of the loopa put together over the past week, but my screen will not start.

The loopa boots up ok and enters test mode. I can trigger the button presses and am seeing responses from the side leds. There does seem to be an issue with the pots as when I push them in they don't register the same as the buttons. Not sure where to look to try and debug this further, any help is appreciated. 

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Hi,

Maybe the jumper powering the display is not installed? Could you post a photo of both sides of your Core PCB?

Best,
Andy

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Posted (edited)

Sure. Thanks again for the help. Also, sorry if some of this is messy, I'm still getting my feet wet with larger scale projects. 

bottom.jpg

top.jpg

Edited by j4ustin

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Seems mostly good but I would check the soldering on the waveshare pins again

bottom.jpg.37fb72f708dfcafc56f211bbd93e3

 

Is the 10uF capacitor correctly oriented? Probably it is but I can't tell from your picture. What is the voltage at the reset pin (should be +3v3)?

Below is the J15C pinout. You can check for interconnections at the top of the waveshare pins. I.e. make sure that you get contact all the way through.

LoopAJ15C.thumb.PNG.1e8adbefbbb904329b18

Net N$9 is the chip select signal that goes to pin 15 of IC2 (also check the soldering there).

And here is the same for the display/plate with the connections labelled.
LoopAJ15C_plate.thumb.PNG.55eaac8df72838

 

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Ah, one more thing: make sure that you use a decent PSU for the USB/power. If the PSU is weak or noisy you might get unstably power for the display. Good luck!

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I checked for continuity between the J15C and the waveshare pins then all the way to the display from the j15c on the bottom of the board. All of the connections are being made correctly and the reset is showing 3.3v as well as the 3.3v header on the display itself. There is continuity between the Net NS9 and the IC2 header 15 pin as well. 

 

Another symptom I noticed that could be related to the screen is that my pots and buttons are only sometimes triggering the lights as registering input when testing with a jumper on the buttons or pushing down the encoders. That behavior makes me think that maybe the two might be related since the connectivity between the screen and the waveshare seems intact. 

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Hmm, did you try reflowing the joints? How is the unit being powered? Is the LoopA firmware loaded? Are you running in test mode (no SD card)?

You could check the above-mentioned pins for shorts to 0V/3v3 or even to each other, so check a) adjacent pins on the J15C header and b) pins on the waveshare breakout,

Happy to take a look at the soldering of the other boards. You can also load MB_NG and check if your DIN is working as expected from MIOS Studio (set debug on).

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Posted (edited)

Just now, latigid on said:

Hmm, did you try reflowing the joints? How is the unit being powered? Is the LoopA firmware loaded? Are you running in test mode (no SD card)?

You could check the above-mentioned pins for shorts to 0V/3v3 or even to each other, so check a) adjacent pins on the J15C header and b) pins on the waveshare breakout,

Happy to take a look at the soldering of the other boards. You can also load MB_NG and check if your DIN is working as expected from MIOS Studio (set debug on).

 

I reflowed every joint and checked the soldering on pretty much every header. 
 

im powering with a usb into my computer. Have tried with 2 usb cables and a usb wall jack as well. 
 

validated the loopa firmware is in there. Can see the io options in my daw with the loopa plugged in. 
 

it is in test mode. I’m seeing the light cycling as in the video test mode. The side screen leds all light up and the button leds all cycle through correctly as well. 
 

I’ll check for shorts and the din next. 

Edited by j4ustin

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Here are the other pcb's. These came out cleaner than the base. Maybe I missed something, but I've been through the video feels like twice now. 

base-front.jpg

base-front.jpg

plate-back.jpg

plate-front.jpg

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Got it! Turns out i cut a trace between the j15c header 4 and the pc9 header on the waveshare. Must have missed that test when I was going over it earlier. Still have the encoder issues, so that's next, but feeling better about this though. 

Going to have to look closer to ensure I didn't cut any other traces on the board which may be causing the encoder / button issues. 

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@j4ustin good progress! Just wanted to recommend to use a scope (or even a DMM) to see if there is proper digital data arriving at every OLED pin 4, 7, 8, 16 and 17. If you've got the display and the LEDs sorted, you're mostly there :) Cheers!

Best regards,
Peter

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Yeah! Feeling better now. Any tips on where I could look to fix encoder presses and button presses? None of those are registering with the boards. I am seeing the led's all lighting up for both the side of the screen and the buttons. I also see the animation for LoopA Testmode

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