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!