DIY Mutable Unsuccessful Builds

[Altitude909]

post a better pic, i'll confirm. You can always remove it and see if the stm will work then

[eeling]

How's this?

[Altitude909]

STM looks ok, 8731 does not though. the dimple should be round, not flat and that chip looks sanded, the markings are off center also (thats the old CS logic logo, my pic is of the last production run)

[Obscure]

Is it absolutely necessary to use exactly the capacitors listed in the BOM? I can't find the specified capacitors, but there are exactly the same ones with slightly larger tolerances. For example, 5% instead of 1% or 10% instead of 5%. I'm not sure, but I don't think it should be a big problem. How do you think?

[eeling]

STM looks ok, 8731 does not though. the dimple should be round, not flat and that chip looks sanded, the markings are off center also (thats the old CS logic logo, my pic is of the last production run)
PXL_20230313_170505757.jpg

That tracks. the 8731 and the STM were the only components not sourced via Mouser or similar. I was a bit sus about that. It doesn't seem like this part is available anywhere, and no equivalent in the same or similar footprint. Any ideas?

The reason I didn't bring this up is that I was under the impression that my PC should detect the STM regardless or the 8731 being present?

[Altitude909]

I had this exact case with a fake 8731, it locked up everything. What is your device measuring for current draw?

Problem for you is that those are now end of life, no more being made and IDK of any drop in replacements

[eeling]

I've got a replacement on the way from the kind folks at AmazingSynth. Will do a swap out! Thanks Altitude!

I'll update when I've made the swap!

[eeling]

Replaced 8731. Looks same as yours. No change - still cannot connect to ST utility.

[m12386]

Replaced 8731. Looks same as yours. No change - still cannot connect to ST utility.

Check the continuity of the mini STM header and the pins on the STM. Where did you buy the STM from? LCSC is the only reliable vendor I was able to get them from months ago.

[eeling]

Thanks for the message. Continuity is between JTAG header and STM pins is fine. STM was purchased from a UK based ebay seller. They have good feedback and insist their STMs are legitimate. I'm unconvinced but hopeful.

[m12386]

How's this?

I could be wrong, but the notch at the bottom left looks strange. Have you tried going over it with acetone/nail polish. Also, I just found these in stock: https://tinyurl.com/2s3eujvu

[BlackieDawless]

Okay I am so sad but not giving up on an Antumbra Knit DIY build. Please be warned this board visually is the stuff of nightmares, and I have lost sleep trying to get it to work. Everything went together fine, I used only Mouser parts and the ST microcontroller is from the last MI stock that Pusherman bought up. I know the pins look messy, but I zapped out almost the whole board and there is no shorts that I can find, except those blobs where they are all ground anyway.

Firmware flashed fine, but when I turned the module on, there was no audio out of the AUX, and no V/Oct control. I will say the firmware updated fine, and I was getting sounds out of at least some of the models that I would expect, but only out of the main out. OKAY, then I took it apart and re-flowed some of the joints, and now I get no sound at all out of the thing, and the lights give me different sorts of merry time Christmas patterns, or don't come on at all. The jack lights are all on and look perfect.

I probed the DAC and all the pins are getting 3.3V, and are connected to the ST chip at the appropriate pins. The 072 chip is actually an 082 but I am guessing this shouldn't be an issue? I did try to re-flash the chip and it seems to be completing, but check out the photo if you think otherwise! I thought it loaded more the first time I did it, but I have been drinking heavily trying to figure this out so maybe I am losing it...

Okay this is a novel, great story bro, I know. The traces started pulling up, so I had to add some wire to the board, so please don't judge me, I am very sensitive right now! If anyone has any brilliant idea for places to check, I would be super appreciative. I have access to a scope and meter and such, but maybe I just need a virtual hug to get through the situation I find myself in!

PRE THANKS EVERYONE!

[m12386]

IC6 and IC7 pins look bridged, maybe the TL082 as well

[BlackieDawless]

IC6 and IC7 pins look bridged, maybe the TL082 as well

I know where you mean - they are common grounds on the bottoms there (3 pins on both chips) and are indeed bridged. The 082 has 8 clean pins although I know the pic looks bad! Thanks for looking for me!

[BlackieDawless]

Okay, I know folks have been worried about this Antumbra Knit build, so just a little update:

After some re-flowing and mucking about including a refresh and firmware update for the 20th time, I can get sound out of the OUT that can only be described as Teapot Boiling Meets Kraken Scream, although it does seem to change when you press either button. Still no audio out of the AUX, I think all the pots work fine as I can change how the kraken screams with each of them. Still no LEDs lighting, but every once in a while upon startup, they will all light orange, so my guess is they are at least not completely fried.

Arrrrgh! Can anyone suggest to me what isn''t broken provided the above symptoms? Like does the fact that some sound is coming out and changes based on button presses suggest the ST chip is fine? I am at the point where I will probably start replacing IC's starting with the cheapest first, but if anyone has brilliant ideas I would love to hear them. I have a working PLAITS right next to this one and 1) it sounds so much better, and 2) it's sort of mocking the KNIT like "broh, get your shxt together...." c'mon let's help this poor fella out!

[eeling]

Got my St-Link connecting and have apparently flashed the MCU with Parasites.
Was getting four red lights, sound passing but no activity elsewhere. Attempted to follow the calibration instructions, sent 1v in and within a 10 seconds R11 burned up.
What the heck?!

R11 = 4.7Ohm connected between IC7 (LM1117-3.3) and C2 (47u electrolytic)

[arthurdent]

Got my St-Link connecting and have apparently flashed the MCU with Parasites.
Was getting four red lights, sound passing but no activity elsewhere. Attempted to follow the calibration instructions, sent 1v in and within a 10 seconds R11 burned up.
What the heck?!

R11 = 4.7Ohm connected between IC7 (LM1117-3.3) and C2 (47u electrolytic)

I built a Clouds a couple years ago, it didn't work at power-up so I was troubleshooting, checking voltages with a meter when one of the probes slipped, R11 started smoking and burned up. I'm guessing I shorted something with the probe that caused it to smoke. So I'd start looking for shorts if I were you.

ALSO, as I recall, the SMD components on my Clouds were 603's EXCEPT for R11, it was a 1206. I assume that was done because it's in the power supply circuit and the larger size is needed for the load. Did you use a 1206 or a 603?

[eeling]

No probes involved at the time of explosion but I will certainly go on the hunt for a short

Your memory is spot on, R11 is a 1206

Edit:

Can't find any short. The voltage regulator LM1117MPX-3.3/NOPB was unavailable so I used: LM1117MP-3.3/NOPB, NSC, 1 Low Dropout Voltage, Voltage Regulator 800mA, 3.3 V

Alternative crystals were used as well, but matched on specs. via mouser.

I'm at a complete loss.

[blankpanels]

Back with another nRings issue - so I had no issues flashing the MC (apparently) - I compiled the hex files with vagrant all fine, and used a cheapo chinese st link v2 and the older ST link utility. Both the bootloader and firmware went on fine, so I added all the through-hole stuff.

On powering the module it seems like it went into the firmware updating mode with the two LEDs flashing amber, then it changed to just the mode LED being illuminated a mostly solid but kind of weak red. I've tried the classic off and on again a few times, sometimes when holding the poly button on startup I can get it to go into the firmware update mode for a few seconds but it always goes back to the single red LED and the module doesn't respond to any input.

Does anyone know what the single red LED would represent?

Flashing the MC was done with the 3.3V from the st link - during the process it said it was done in low power mode, but it connected fine and verified fine, so I assume I'm okay there. Plus the LED behavior for a few seconds was consistent with the rings firmware. Either way I'll try reflashing and take some more measurements and reflow some stuff tomorrow.

So I'm still having the same issue - where (I'm guessing) when the capacitors hold no charge my nRings seems to work fine - but after <30secs everything stops working and the mode LED lights a very dim red (1.58V from mode LED cathode to red leg, 1.3-1.4V on other LED legs). Is this an error code I can find the meaning to somewhere?

When the caps aren't holding charge I measure 312Ohm to ground on both the 3v3 and 3v3A lines - when charged I get more like 360Ohm to ground. Does this seem like the normal resistance to ground from 3v3 rails? When the module is briefly working I get no change in the output from the LM1117.

I'm not getting anything feeling hot, I've reflowed everything, continuity checked every trace that carries power including -10V ref, reflashed with eurorack power. The only time I had any burning smell was when I applied eurorack power and 3v3 from my cheap chinese STlink (which just directly applies 3v3 not like the official STlink)

When I put in an audio signal:
-I do get signal to CODEC pin 23 (SDIN) and 24 (SCLK) pins of CODEC (both are digital input from MC based on data sheet)

- Pins 5 and 7 from CODEC to MC (DACLRC, ADCLRC) getting no signal - but should be sample rate clock which I'm assuming I won't pickup with my soundcard scope? (actual scope on order)

- CODEC pin 4 (DACDAT) get a digital signal on - which should be audio data sig from MC?

- CODEC pin 6 (ADCDAT labelled I2S_SIN trace to PB14 on the STM) digital output from codec got a signal on for a bit, then nothing

Does this mean my codec is busted? as getting signals on the input to the codec, and also from the MC to the codec but then nothing from the digital output? But why would it work fine for a bit when the caps are discharged and there is less resistance to ground?

I also traced CV signals which all get to the right pins on the MC, but from testing IC4 I couldn't get any of the MUXing or adder signals on my scope? I'm kinda guessing again that it's due to not having a proper scope.

The other thing I noticed probing around with my multimeter was reverse flow on the clamping BAT54SLT1G. I'm getting 0.25V in forward bias - but 0.398V reverse bias with my multimeter in diode mode? Any ideas what the deal is there?

Really don't get what is going on here

[eeling]

FYI I've put a message in the 'seeking DIY builders' thread looking for someone UK-based who might troubleshoot my Rangoon/Monsoon.

If anyone here is interested please hit me up. I have a full rangoon PCB/panel and components set which can offer as payment.