Pycom module and devkit repair - Page 1
Forum section: electronics / repair

author: Krotow
author_rank: Regular Contributor
timestamp: October 26, 2024, 10:17:01 pm
content: My workplace uses Pycom GPy and Lopy modules in some of our projects. During time some of them broke or got damaged by lousy people like me or coworkers by connecting them in wrong way, attaching signals with too high voltages to module inputs etc. Now I have a nice heap of dead modules on my desk. And one deadPysense 2.0Xexpansion board that had stopped working when coworker plugged freshly damaged Lopy in it in a hope to reflash it. Pycom recently croaked, was sold out and new owner has no intention to manufacture or support existing Pycom hardware. Now we are running out of working modules. Decided to so something and look inside dead ones in a hope to fix at least some of them. Almost everyone looks fine.Except one with cracked small square chip at corner.Thermal camera however show that in all modules ESP32-D0WDQ6 MCU and one small square form chip near large capacitor - the same that cracked in one of modules - are trying to become little suns.Seems in all dead modules ESP32-D0WDQ6 MCU is beyond repair and must be replaced. Luckily it is obtainable for 3$ in several stores like Mouser etc. and Pycom firmwares are still available for download. Small square chip remain unknown.Correction here:It is switching voltage regulator with 3.3V output. And in most modules it become hot because is shorted by dead MCU thus would work with good MCU. Still I would like to know the real part number. Cracked one certainly is gone and would like to have some spares as well. Almost all of these chips have black surface without anything on it. Except in one of modules it have faint NS19 marking around first pin dot.

author: dpape
author_rank: Contributor
timestamp: October 28, 2024, 12:19:24 am
content: Hi,We had the same issue of not having any GPy modules available any longer. We could not find an alternative and therefore made a pin compatible and software compatible alternative. At the same time it is a serious upgrade with lower power consumption, ESP32-S3 chip, better software support, more pin flexibility, ...All info is onhttps://www.quickspot.io

author: Krotow
author_rank: Regular Contributor
timestamp: October 28, 2024, 07:35:38 pm
content: Due to absence of Pycom modules we too developed similar ESP32-S3 based module more tuned to our needs. Now in waiting for new PCBs.Removed all failed packages from dead Pycom modules for damage assessment. Turned out that in some only voltage regulator fried, these are usable when powered from 3.3V via 3V3 output. In some only ESP32 chip fried. The rest has both chips fried.Still would be nice to know which voltage regulator is used in original Pycom ...py modules. 5.5v max input voltage, 3.3V output voltage, 1.2A current, BGA-like package with balls in 2x3 layout (WLCSP-6 ?) with 0.40mm (?) pin space. Has tiny NS19 marking around 1st ball dot. Ball 1 is Vout, BALL 3 - Vin, ball 4 - GND, ball 5 - presumably FB, ball 6 - most likely EN(able). Unusual inductance - 3.4uH which most likely is 3.3uH in circuit diagram. Switching regulators in tiny ball packages usually have 1.0uH or even 0.5uH or 0.4uH inductance. Might be this is some sort of adjustable buck-boost regulator with adjustable output voltage. Spent all evening in searching for something compatible, no success so far.

author: Krotow
author_rank: Regular Contributor
timestamp: October 29, 2024, 12:21:31 pm
content: Good people in EE related FB group pointed to LM3281 as correct switching regulator in Pycom modules. Online search for Pycom with LM3281 dug out few comments and Github records about that, first entries confirmed the LM3281 as correct part number. It also proved that both Google Search and ChatGPT are equally useless for searching for component without knowing the manufacturer and part series. I will try to get luck with LM3281 and tell about what happened.Still unclear why Pycom used 3.3uH inductance where LM3281 datasheet specify 0.26-0.47uH. Probably wanted to get less power demand and heat as possible.

author: Krotow
author_rank: Regular Contributor
timestamp: March 19, 2025, 05:01:59 pm
content: Received Pycom module replacement parts a while ago, but only now found time for repair. Went pretty smooth. ESP32 didn't cause any problems. One of LM3281's made a short at first - it was solder bridge under IC due to too nervous poking it with tweezers during soldering processSecond heating blew it into place and it started working. I kinda hate BGA pins for that, however they seems native now for some chip types and the only solution is learning how to properly solder BGA without expensive industrial equipment. The real problem was RF shield covers who refused to solder back due to thick grounding behind them. Had no wish to boil poor modules or bridge several 0201 and 10500 size components an so left them uncovered. For development purpose only they are fine as they are.Dead Pysense 2.0 board was dead become firmware glitch. Reflashing fixed it.I'm curious which IDE people now use for MicroPython programming. Especially on Linux and MacOS. We used VS Code + Pymakr for a while. However Pymakr is now very obsolete due to Pycom demise. It also doesn't support ESP32-S3 based modules (we made our GPy alternative based on it). Didn't found nothing useful for VS Code so far. From the rest only Thonny IDE turned out compatible with both Pycom xPy and other ESP32-x brotherhood. It was pretty glitchy though till in last month update that magically fixed most problems with it.