Building log for "EEZ BB3 Enclosure & Bare Boards" - Page 1
Forum section: electronics / projects

author: prasimix
author_rank: Unknown
timestamp: August 25, 2020, 08:32:58 am
content: Quoted fromhere:Quote from: Ranayna on August 08, 2020, 09:24:43 pmMore then 50 people backed "EEZ BB3 Enclosure & Bare Boards" kit so far! Therefore I'm opening a new topic where we can discuss assembly, problems, share building pictures and ideas but also possible improvements that could be added in new versions.The starting point should be theAssembly instructionspublishedhere.I am at your disposal and I will do my best to make the installation as painless as possible. Mouser should initiate pick up at any time now so kits can be expected in the coming days.

author: exe
author_rank: Unknown
timestamp: August 26, 2020, 12:40:08 pm
content: I have a question about verifying that DCP405 works correctly. Some hints were already given herehttps://www.eevblog.com/forum/crowd-funded-projects/eez-bench-box-3-sequel-to-eez-h24005/msg3196838/#msg3196838and herehttps://www.eevblog.com/forum/crowd-funded-projects/eez-bench-box-3-sequel-to-eez-h24005/msg3203298/#msg3203298I wonder what is the minimum voltage that DCP405 accepts? Looks like for testing purposes it can be supplied from even less than 12V.

author: prasimix
author_rank: Unknown
timestamp: August 26, 2020, 12:51:57 pm
content: Quote from: exe on August 26, 2020, 12:40:08 pmSet by R13 / R16 it should be about +27 V (when EN input goes below +1.2 V).

author: prasimix
author_rank: Unknown
timestamp: August 26, 2020, 04:41:09 pm
content: I guess this will help: I updated the content of the project pages on the web. I also put those documents in a newly createdfolderon GitHub where you can also find aPDFwhere all the documents are merged together.

author: Corona_Spark
author_rank: Newbie
timestamp: August 28, 2020, 07:10:22 am
content: The marked parameters of FB1 FB2 FB3 in the schematic diagram of DCP405 are 60R@100MHz, and the parameter in the BOM is 1k@100MHz.In addition, the rated current of the inductor RN 112-4-02-0M7 is only 4A, which does not seem to meet the design requirements.

author: prasimix
author_rank: Unknown
timestamp: August 28, 2020, 07:20:48 am
content: Thanks, I'll change that is schematics since 1K were used.

author: prasimix
author_rank: Unknown
timestamp: August 29, 2020, 07:04:09 am
content: Follow up on message#288from another thread: I have 7 DCP405 modules left in the "junkyard". I can send them worldwide except at this time to Australia.

author: exe
author_rank: Unknown
timestamp: September 06, 2020, 06:48:44 pm
content: I powered one of dcp405 modules from a power supply. It seems aux voltages (+-9V +-5V) are fine, but on IC1 (prereg) I have RUN pin low. Is this normal? If so, I assume pre-reg is disabled by default and enabled by MCU. Is there any way to enable it for testing purposes?

author: prasimix
author_rank: Unknown
timestamp: September 06, 2020, 09:23:06 pm
content: Sure, apply +5 V to IC1 RUN input (pinto enable it. When enabled, you should get about +4 V on pre-regulator output (PREG_OUT+).

author: exe
author_rank: Unknown
timestamp: September 07, 2020, 02:32:10 pm
content: I applied +4V to RUN pin, and got +4.7V. Looks OK to me... I also removed the heatsink, looks like all ICs have correct orientation. IC9 has alignment issues, but looks to have a good electrical contact.So, I guess, further troubleshooting requires installing it into the power supply? Or there is a simple way to output some test voltage? It seems I need to send some SPI commands to do so.PS not sure if it matters, but both CV and CC LEDs are on.

author: prasimix
author_rank: Unknown
timestamp: September 07, 2020, 02:51:08 pm
content: Yes, you need the rest of the system to continue with testing. Without control, both CV and CC will be turned on, that is fine.

author: exe
author_rank: Unknown
timestamp: September 16, 2020, 05:42:21 pm
content: I tried to buy LRS-150F-48 from Mouser, but they don't ship it to individuals in EU. Is it possible to substitute it? If so, what would be suggestions?I found HRP and HRPG series, which feature active PFC and slightly higher ripple, but have 38mm height instead of 30mm. Will they fit? (e.g., hrp-150-48).Another question, can input be lower than 40V if I don't need full 40V output? I think I'll be happy with less than 30V of full-range output.

author: prasimix
author_rank: Unknown
timestamp: September 16, 2020, 06:18:14 pm
content: Yes, the DC input could be lower, and max output voltage will drop respectively. I'm not sure if Mouser is a right address for buying Mean Well price wise, TME is much better, but with empty stock for F-version. The direct replacement is version with manual switch for AC input that shouldn't be a problem: you need to set it to 230 Vac and TME has over100 pcsin stock.The problem is that enclosure is custom tailored to accept LRS-150 modules. Thicker modules could be housed but ask for a new mounting frame and some extra tweaking.

author: The Soulman
author_rank: Super Contributor
timestamp: September 16, 2020, 06:52:36 pm
content: reichelt.nl has LRS-150F-48 for 24 euro incl. btw (tax).

author: exe
author_rank: Unknown
timestamp: October 18, 2020, 01:06:41 pm
content: I started buying parts for aux ps, mcu board, and backplate and noticed that when using 1-click bom some parts din't make it into the basket (or I don't know how to use BOM). It seems that not all parts are available on Mouser, so I had to use digikey and tme. I suggest checking the following parts:1. AUX PS heatsink2. leds3. idc ribbon cable4. buzzer5. banana socketThe hardest part to find turned out to be encoder, I'm going to replace it either with no-dent version, or 12 dents version. The next challenge was to find MCU. I found it only on digikey.I put my orders already, hope to start assembly next week.

author: prasimix
author_rank: Unknown
timestamp: October 18, 2020, 01:41:10 pm
content: Yes, there is a shortage of MCU, but the last time I checked (about 2-3 weeks ago) Farnell had most of the world’s reserves in stock

author: AkosL
author_rank: Newbie
timestamp: October 18, 2020, 10:20:21 pm
content: Guys, where did you find SRF0703-821M? Looks like it's nowhere even on Octopart.Or is there a suitable replacement part?For the MeanWell power supplies: look at local MeanWell distributor

author: prasimix
author_rank: Unknown
timestamp: October 18, 2020, 10:23:48 pm
content: Same family, anything down to 330 uH should works.

author: exe
author_rank: Unknown
timestamp: October 19, 2020, 07:49:52 am
content: Oh boy, I'm bitten by the same problem again. Why mouser does this?. Worst part: I put all my orders already, so if I want to order this part elsewhere, I'll have to pay for delivery. I'm figuring out if I can provide them VAT of a company of a friend of mine.

author: billrule
author_rank: Newbie
timestamp: October 20, 2020, 12:25:33 pm
content: I know this is basic, but apart from trial and error, is there a guide to which end of the case is thefront?

author: AkosL
author_rank: Newbie
timestamp: October 20, 2020, 03:41:37 pm
content: Quote from: exe on October 19, 2020, 07:49:52 amDid you manage to order it from Mouser? Local supplier is out of stock for that power supply, and got to the point when I have to give my credit card info at Mouser's checkout.

author: Ranayna
author_rank: Super Contributor
timestamp: October 20, 2020, 04:50:46 pm
content: Quote from: billrule on October 20, 2020, 12:25:33 pmLook at the holes. There are a lot more holes on the front side than on the back side, because both the MCU and the BP3C Board are mounted on the front side.This is well visible in the assembly instructions of the 2Channel Kit:https://www.envox.hr/eez/images/bb3_instr_bottom_plate.jpg

author: exe
author_rank: Unknown
timestamp: October 20, 2020, 08:55:36 pm
content: Quote from: AkosL on October 20, 2020, 03:41:37 pmNo, they said it's only for companies. Had to order from digikey. So, I put two orders on digikey, they say I'll have to pay vat on delivery. Hope there won't be any hidden costs like processing (I'm in NL).

author: AkosL
author_rank: Newbie
timestamp: October 21, 2020, 10:05:18 am
content: @prasimix, I hope my last questions for now: do you have any alternative source for these?PMB-1 PCB bracket; polyamide- hot glue?OSY5LU3E34X-3F1A THT; LED 3mm; yellow- just solder in a 3mm led, and bend the legs? or does this have built-in current limiting maybe?Thanks a lot!

author: prasimix
author_rank: Unknown
timestamp: October 21, 2020, 11:37:43 am
content: Quote from: AkosL on October 21, 2020, 10:05:18 amThe same, from TME:PCB-MB-01Quote from: AkosL on October 21, 2020, 10:05:18 amHuh, that one is a real trouble to source, but as you suggested any 3 mm LED with bended legs should be fine.

author: exe
author_rank: Unknown
timestamp: October 21, 2020, 12:32:45 pm
content: Quote from: prasimix on October 21, 2020, 11:37:43 amI bought a green one, this one:https://www.tme.eu/en/details/osg8ha3e34x-3f1a/led-pcb-indicators/optosupply/. I hope it will fit. The led is different, so current-limiting resistor might need an adjustment (or may be not, the specs seem to be the same). Or I find an orange led in a dumpster.

author: prasimix
author_rank: Unknown
timestamp: October 21, 2020, 12:54:34 pm
content: Green is just fine. They are also partially used during AUX PS assembly for campaign fulfillment since yellow one was out of stock.

author: exe
author_rank: Unknown
timestamp: October 22, 2020, 07:38:10 pm
content: I have a question about backplate BOM. I think X4, X5 and X6 should be the same (and they are in csv file), but they are different in this file:https://github.com/eez-open/modular-psu/blob/master/bp3c/BOM/EEZ%20DIB%20BP3C%20r3B3%20BOM.pdf. It also says that X4 should be right angled, but it looks like X5 is actually right-angled. Denis, can you please check? I guess, csv-file is more accurate? Or designating numbers are different on different versions of the pcb?UP: my pcb doesn't match this picture:https://github.com/eez-open/modular-psu/blob/master/bp3c/Images/EEZ_DIB_BP-3C_PCB_top.png. For example, D4 on my pcb is named D5 on the picture. Should I use an older picture or something?

author: prasimix
author_rank: Unknown
timestamp: October 22, 2020, 09:56:40 pm
content: Yes, the BP3C that came with the campaign is r3B2 and is a little different from the version that went into release 1.01 in which r3B3 was released prematurely. Please use files from release 1.0 that contains r3B2 (see attachment).

author: exe
author_rank: Unknown
timestamp: October 23, 2020, 05:55:27 pm
content: Thanks, Denis. Do you remember what were the changes to the project after r3B2? Does it make sense to order new boards?

author: prasimix
author_rank: Unknown
timestamp: October 23, 2020, 06:41:09 pm
content: Not at all in case of BP3C. I just removed one header and use Zener diodes in different package if I remember correctly. All other boards are different story since they needed some real changes to pass CE testings.

author: exe
author_rank: Unknown
timestamp: October 23, 2020, 07:44:11 pm
content: That's good, as I just finished the backplate.As I understand, CE is only needed for the aux supply board? The mcu board is not affected by this?What's your advice: make new boards, or keep the ones in the kit?

author: prasimix
author_rank: Unknown
timestamp: October 23, 2020, 09:51:56 pm
content: Quote from: exe on October 23, 2020, 07:44:11 pmI'm in process of learning what is behind CE marking. No, it is not needed just for AUX-PS module but for a complete solution that could include components that are already passed CE testing. But, surprise, surprise ... I’ve learned in a hard and very expensive way that it doesn’t really mean much: one MeanWellmodel can pass testing, combination of two different modules cannot (conducted emission break limit); one MeanWellmodel can pass testing, add another of the same type and they cannot pass testing (current harmonics break limit). Later issue requirednew AUX-PS, former probably will probably require giving up the LRS-150 model and using one who has a built-in PFC (If I’m lucky I’ll get away with a massive capacitor at the AC input, another option is next AUX-PS revision with PFC for up to three Mean Well modules which I have not yet begun to consider).I learned that the MCU module cannot pass the radiated emission test when the antenna is horizontally polarized if the SDRAM is set as in the r2B4 version. It turns out it can pass ifthe SDRAM is set beneath the MCU.Similarly, DCP and DCM modules broke the limit for radiated emission which also required some modifications (new pre-regulator in case of DCP, PCB redesign in case of DCM). I don't know what else awaits me on the way. The first next thing I have to pass is the current harmonics test. I am not even able to prepare because the documents of the norms that prescribe tests are not free, but literally cost a small fortune if I buy everything (it seems to me over 15,000 EUR).My suggestion: assemble what you have, unless you want to wait uncertain period of time. At the moment, what I can say with certainty is that the design of the DCP module that passed the CE (r3B3) will not change, and for which I only currently have bare PCBs as well as an excess of assembled modules made by a new contractor.

author: exe
author_rank: Unknown
timestamp: October 24, 2020, 09:11:05 am
content: Ah, silly me, I thought it's about safety. Thanks for detailed explanation, I'll proceed with current pcbs.

author: exe
author_rank: Unknown
timestamp: October 24, 2020, 09:56:37 pm
content: Denis, do I need to short any jumpers on any of pcbs?

author: prasimix
author_rank: Unknown
timestamp: October 25, 2020, 05:50:45 am
content: No

author: exe
author_rank: Unknown
timestamp: October 25, 2020, 10:41:42 am
content: Idiotic question, will aux ps work without OK1 optocoupler? Asking because mouser screwed my order and I now have two moc3062 instead of one moc3052 and one moc3062. I'll order moc3052, but I'm impatient to test the board. I guess without OK1 the current will go through the NTC1, but that's no problem for testing without load, right?

author: prasimix
author_rank: Unknown
timestamp: October 25, 2020, 10:52:21 am
content: You can place MOC3062 on both positions. Better then you got two MOC3052.

author: exe
author_rank: Unknown
timestamp: October 27, 2020, 10:00:41 am
content: Potential BOM issue: for MCU board, for "FB1, FB2" the quantity is specified as 1, while it needs two beads. I replaced it with BLM18HD102SN1 which is the only ferrite bead of this size I have. But because it has higher DC resistance (1.8Ohm) and lower current rating (50mA) I expect ethernet won't work properly (I don't need it anyway).

author: prasimix
author_rank: Unknown
timestamp: October 27, 2020, 12:06:13 pm
content: Thanks, now it isfixed.

author: exe
author_rank: Unknown
timestamp: October 27, 2020, 09:35:53 pm
content: My friends, I assembled the mcu board, connected it to the aux-ps board, connected it to my computer, pressed boot0 button, switched on power and then.... nothing happened. Question: is DFU mode available on blank mcu by default, or it needs pre-existing firmware (i.e., the first time I need to flash the board via st-link interface)?

author: prasimix
author_rank: Unknown
timestamp: October 27, 2020, 10:31:43 pm
content: Sorry to hear that.No, you don't need anything to download firmware in the brand new (i.e. completely empty) MCU. Therefore, no need for STlink or external programmer. You even don't need to assemble a whole module just to establish communication for firmware download. It can be done with minimum parts: LDO (3.3 V power), Boot0 switch, MCU (i.e. everything from Sheet 2/5) and USB connector with R28, R29 in place.Be sure that switch (which is very tiny) are really pushed on while power is applied.For the beginning check if you have 3.3 V on MCU.

author: exe
author_rank: Unknown
timestamp: October 29, 2020, 08:15:58 am
content: Thank you very much, I'll check on this.Meanwhile I found that I didn't buy the ethernet port (LMJ30288115CNL) because it's not available from mouser.

author: prasimix
author_rank: Unknown
timestamp: October 29, 2020, 08:20:13 am
content: Currently it is available only atTME, but there is a worrying info thatProduct available till the stock lasts. It seems that I have to replace it with something else in the next release!

author: exe
author_rank: Unknown
timestamp: October 29, 2020, 09:00:38 am
content: I think there is an alternative ethernet port (the bom provides alternative sku) that is still on sale on tme.Meanwhile I found the problem: I soldered the mcu the wrong way: it has multiple corner marks, two large ones and one small. I used one of big ones to orient the chip. What a bummer... I guess I should not do soldering late at night. I'll try to flip it, but chances are not great that it will work.

author: prasimix
author_rank: Unknown
timestamp: October 29, 2020, 09:02:36 am
content: Ouch, that is exactly what happened to me with my first prototype ... and that was in the middle of the day.

author: prasimix
author_rank: Unknown
timestamp: October 29, 2020, 10:38:57 am
content: Quote from: exe on October 29, 2020, 09:00:38 amYou're right the first choice is LMJTAB881243ML but also only available from TME.

author: exe
author_rank: Unknown
timestamp: October 29, 2020, 10:41:26 am
content: Phew, seems to be working after all. At least I was able to upload firmware. I'd like to share my experience so other people won't do same mistakes.Not the best soldering, but good-enough for Australia. A few things I messed up. One is my zener flew away when I tried to grab it with twezers. I replaced ZD1 with two zeners (16V+7.5V). I think I damaged my tweezers by using them to open resistors on tape.Then I couldn't solder the usb port, it seems it's meant to be soldered with hotair or reflow. I removed rear tab of the connector to get access to pins.I ran out of cr2032 batteries, so I put cr2025, hope it will work.The boot0 button seems damaged by flux: it's stiff, but seems to be working.In some cases it might worth soldering ICs first, and then decoupling caps as they get in the way. But I mostly used hand soldering, users using hotair probably find it much easier to solder components. I put plastic parts at the very last because: 1) I was worried to damage it with hotair and flux 2) it's easier to work with flat board without components sticking from it. If I was assembling it again, I'd use solder paste and hotair gun for most components, rather than soldering iron.Oh, and double-check the BOM.Now time to assemble the enclosure...

author: exe
author_rank: Unknown
timestamp: October 29, 2020, 10:59:13 am
content: "Do not power on the MCU module without the display connected or with a loosely connected flexible display cable. Doing so may damage the power supply of the display backlight located on the MCU module." Oh shi~...

author: Kleinstein
author_rank: Super Contributor
timestamp: October 29, 2020, 11:08:26 am
content: With the zener diode(s) in place there is a good chance the backlight drives does survive. It would be the zener that gets quite some heat. So having 2 may have helped.

author: prasimix
author_rank: Unknown
timestamp: October 29, 2020, 11:15:24 am
content: Quote from: exe on October 29, 2020, 10:59:13 amApplicable only to assembled MCU modules where ZD1 with too high voltage (30 V) is mounted. In the last BOM list it is lowered to 24 V and it should be fine. If accidentally a failure occurs, there is no damage to the display. All that can happen is that D2 breaks.

author: prasimix
author_rank: Unknown
timestamp: October 29, 2020, 11:21:54 am
content: Quote from: exe on October 29, 2020, 10:41:26 amCongratulations! The choice of method obviously depends on one’s soldering skill. I still manage to solder almost everything by hand. On this module I only used hot air for the LDO thermal pin. For USB you need a sharp tip.There is one other thing that I did not mention in the building instructions and it is worth the effort is to further strengthen the SD card holder. Without that, it could easily happen that the metal shield pops out of the slot the first time you carelessly insert the card. Therefore, the metal shield should be soldered at three points as in the picture.Attention! While this seems like a trivial task, it’s not for dilettantes like AssemTec Europe (aka Bolek & Lolek Enterprise). Namely, they managed to destroy over 30 holders that I had to replace. What's the problem? They applied too much solder that the solder spilled on the other side so the SD card could no longer be inserted!

author: exe
author_rank: Unknown
timestamp: October 29, 2020, 12:14:03 pm
content: Quote from: prasimix on October 29, 2020, 11:21:54 amVery interesting, the sd card holder I bought have only one tab on metal shield. I have this one:https://www.molex.com/molex/products/part-detail/memory_card_socket/5033981892(there is 3d view on the right). Anyway, I'll just be careful, that's the least problem I have.I did the first power up and... nothing happened except the fan worked for 10s or so. Is it possible to see any debug log via, say, usb? I wonder if it's "just" a display issue, or the board doesn't boot at all. I think this kit is a bit beyond my skills but I don't give up. I just need more spare parts. I suspect the mcu can be partially destroyed due to previously incorrect orientation. I'll try to see if there is any signal on display pins with my oscilloscope and 10x probe.PS I forgot to buy front push button, but I can 3d-print it.

author: prasimix
author_rank: Unknown
timestamp: October 29, 2020, 01:14:08 pm
content: Quote from: exe on October 29, 2020, 12:14:03 pmYou have the right holder. It has only one tab, but it is possible to solder it on all three points.Quote from: exe on October 29, 2020, 12:14:03 pmI'm confused now. I thought you changed the MCU because it would be a real miracle if it survived the wrong assembly. How you manage to download firmware if it cannot power up? Did you disconnect USB cable before power up? On the power up even if some errors are detected, with functional MCU you should hear the sound (OK, that presume that audio path is functional).

author: exe
author_rank: Unknown
timestamp: October 29, 2020, 04:15:12 pm
content: Quote from: prasimix on October 29, 2020, 01:14:08 pmNo, I just re-soldered the mcu. DFU works with it, but no sound, and tft brightness output is just 4.8V (I don't see pwm signal controlling brightness). Ordering new mcu...

author: prasimix
author_rank: Unknown
timestamp: October 29, 2020, 04:18:31 pm
content: Yes, I think that is the right move.

author: Kean
author_rank: Unknown
timestamp: October 30, 2020, 09:32:52 am
content: Quote from: prasimix on October 29, 2020, 11:21:54 amYes, one of mine seems to be suffering from this. Getting the microSD card in was not easy, and getting it out again...I should have a suitable replacement part in stock.

author: billrule
author_rank: Newbie
timestamp: November 01, 2020, 04:58:02 am
content: ....wait....so you are implying we should read those wordy things BEFORE we ...O....#$%$@!!

author: Kean
author_rank: Unknown
timestamp: November 01, 2020, 05:52:49 am
content: Quote from: billrule on November 01, 2020, 04:58:02 amOK, so what did you do?

author: exe
author_rank: Unknown
timestamp: November 02, 2020, 08:43:04 pm
content: I replaced the mcu with a new one, flashed firmware with "sudo dfu-util -a 0 -D ~/Downloads/bb3-v1.4.dfu", removed usb cable, power-cycled the board, and... nothing. I checked that 3.3V is present on decoupling caps, I saw a ~25MHz sine across Y1 oscillator (amplitude ~1V or thereabout), I checked that NRST pin is at 3.3V (measured on C8 capacitor footprint, no C8 is installed). No signal is present on Q2 (buzzer driver). I tried to start the board with and without screen, with and without backplate. I tried to replace the IDC cable too (just in case), no luck.I suspect that there could be a soldering issue with RAM or something (for some reason solder doesn't wet pads well) and mcu stucks in initialization. I'll try to build a custom firmware that just beeps. And I'll try to resolder pins and I'll use more aggressive flux.

author: exe
author_rank: Unknown
timestamp: November 02, 2020, 09:05:01 pm
content: Oh boy, I added tons of flux and solder on SRAM chip, thoroughly resoldered it and... it seems to be working! I wonder if the previous mcu worked too, but I'm not gonna recover it from the trash bin and resolder.

author: exe
author_rank: Unknown
timestamp: November 03, 2020, 05:32:21 pm
content: Okay, the "easy" part is done, now it's time for my lovely defective dcp405 modules. Denis, how do you test them?I quickly checked them. Two of dcp405 seem to be half-working. At least they are detected and output something, but I see some weirdness in their behavior (such as voltage doesn't go to zero, or OVP triggers when trying to change voltage). One module doesn't recognize. I fixed one soldering joint on it, but it still doesn't recognize. I tried to initialize the module, but somehow I destroyed the sd card slot. No visible damage, it's just the card doesn't fit in. When I forced it in, it still not detected. Adding a new one to my next order...

author: prasimix
author_rank: Unknown
timestamp: November 03, 2020, 05:40:07 pm
content: Quote from: exe on November 03, 2020, 05:32:21 pmDid you try to initialize it with MicroPython script as described inassembly instructions?If OVP trips that is clear sign that CV control loop is not functional, i.e. cannot maintain set voltage.Most of the junkyard boards are ready for complete resoldering or moving all parts section by section to the new PCB.Also most of them should have properly functioning bias power supply (IC2, IC5, IC6) but still that is the first thing to check.

author: exe
author_rank: Unknown
timestamp: November 03, 2020, 09:22:23 pm
content: Can I use an IDC cable to connect module outside the enclosure? Say, a 30cm cable, do you think it will work?PS found why my sd card doesn't work. When I soldered front right corner the solder flowed inside and blocked the right side of cardhole.

author: prasimix
author_rank: Unknown
timestamp: November 03, 2020, 09:41:48 pm
content: We have to check that, currently there is an active discussion about that on #prototyping channel atDiscordserver

author: Kleinstein
author_rank: Super Contributor
timestamp: November 04, 2020, 10:39:39 am
content: There is a good chance it can work with some 30 cm of cable. It is not ideal, but chances are not so bad. The critical signal would be the SPI clock and if there is significant ringing with the added line. It would help if the driver pin at the µC side is not set to highest speed, even if the means lowering the SPI speed a little.

author: exe
author_rank: Unknown
timestamp: November 04, 2020, 09:25:56 pm
content: A quick update on my build:1) soldered fan pin in reverse way. The interesting thing is the fan still worked, but readback didn't work and MCU thought the fan is faulty and was spinning it at full speed.2) fixed the sdcard slot. Turned out card detect pins on the back were not soldered (I didn't notice them). The card holder got some cosmetic damage because I tried too hard to insert a card with a solder blob inside, but seems to be fully working. The blob inside was removed with a thin solder wick.3) fixed all the dirty hacks I applied (put the proper optocoupler, replaced zener, replaced boot0 button, put proper FB1 ferite bead, installed ethernet socket, etc).It seems that active discussions are happening on discord, so I think I should go there, and leave this thread only to report results.PS I'll order a long ribbon cable to see if it just works.

author: exe
author_rank: Unknown
timestamp: November 07, 2020, 11:54:45 am
content: Quick update on my build. I managed to fix two out of three dcp405 modules. One had soldering issue on shunt sensing opamp, another one had output enable resistor badly soldered (see the pic, although it was the other side of resistor, I wasn't able to take a good picture of the problem). In many cases visual inspection didn't help much, I had to probe with a dmm to detect failures. Soldering is actually quite bad, even though at first glance it doesn't appear so. I suspect they have problem with soldering paste, the alloy feels brittle or not completely melted or something. The board also produced cracking sounds when I dried the board with hotair (the temperature was well below 100C, I could keep my hand). I hope that weren't solder joints cracking...My last dcp405 is a bit more difficult. I resoldered a few ICs with hot air, many joints resoldered with my leaded solder just in case, also found one disconnected capacitor (see the pic). The CC mode still misbehaves: it outputs 21uA when set to zero on low current range, and oscillating ~0.2mA on hight current range. Sometimes it outputs 22mA on that range when set to zero amps. I'll continue my investigation.Meanwhile I found that common ground coupling didn't work. It was T2N7002AK,LM from toshiba which failed open between source and drain). My very-very first dead mosfet! I replaced it, and replacement died the same way... ESD problem? EMF from relay? I checked zenner across relay, it appeared to be working. I replaced the mosfet with 2N7002-7-F from diodes inc., and it worked. Weird, isn’t it?

author: exe
author_rank: Unknown
timestamp: November 07, 2020, 12:35:03 pm
content: Small update, there is indeed a lot of oscillation on the last dcp405. Looking at broad noise spectrum I suspect pre-regulator is not functioning well.PS I also checked my meanwell 48V supplies to be sure the noise doesn't come from them.

author: exe
author_rank: Unknown
timestamp: November 07, 2020, 01:34:25 pm
content: Resoldered C13 capacitor (the one on the previous picture), and it seems the module works as expected, or there is an intermittent failure which disappeared.So, now I have three modules, they work the same way. So, either they all fixed now, or they are all broken in a way I don't know yet. I've done stress test, all are capable of outputing 0.2V-40V, 50mA and 5A. Minimum current is ~22uA in 50mA range, I wonder if other users have the same.

author: Kean
author_rank: Unknown
timestamp: November 07, 2020, 02:09:27 pm
content: Quote from: exe on November 07, 2020, 01:34:25 pmSounds like good progress. I've repaired 2 of my 3 so far. Did you run the downprogramming test suggested by prasimix?https://www.eevblog.com/forum/projects/eez-h25005-a-possible-successor-of-eez-h24005-programmable-power-supply/msg3303354/#msg3303354QuoteAlthough the low range current display doesn't work in the 1.4 FW, you can still set low currents. I took some low current measurements (as suggested by a friend) via a 10k resistor and 20V compliance voltage. Set at 100uA was reading about 97uA (3% low). Set at 20uA was reading about 15uA. Anything lower (including 0) delivered 10uA. My low range calibration could possibly be a bit better, but I'm pretty happy. Measured with my Keysight 34465A.

author: Kleinstein
author_rank: Super Contributor
timestamp: November 07, 2020, 03:46:12 pm
content: From the pre-regulator there can be some current for the control: there are about some 50 µA flowing through R7 and R10. Depending on the voltage some of this current bypassed the load, but not all. So the minimum current is expected to depend on the output voltage. With low voltage is may not go much below 50 µA, with more voltage ( > 0.5 V) the 50 µA should flow trough R27, R32 so that the load current could approach zero.

author: exe
author_rank: Unknown
timestamp: November 07, 2020, 08:32:52 pm
content: With 10K resistor I too have ~10uA. Indeed, as Kleinstein says, the min output current depends on output voltage. With 51k resistor I got ~3.43uA output current at ~0.18V drop. Cool!One weird (or not) thing. I got really weird oscillations on output, something I can't explain. I connected my trusty (not anymore?) analog discovery 2 to see if downprogrammer works. The good news it does. But what I also noticed is horrible ripple on output that didn't depend on power supply settings. The way I "fixed" it was... attaching ground wire to the module. I don't get how this works. What's worse, when I want to zoom in on ad2 and used 500mV sensitivity, I got channel overloaded (see last pic). Floating my laptop didn't help.Omg, I got a ground loop that made my ad2 crazy. And the loop was due to... externally mains-powered sound card. Still, I don't get, how attaching protective earth connection to the power module helped. Shouldn't power modules be isolated?PS attached a shot with DP on and off, jumping between 0V and 5V, current set to 1A, 10ms each step. With small current it was going into CC mode due to output cap.PPS I ran out of broken dcp405 modules, bought another one for repair.

author: prasimix
author_rank: Unknown
timestamp: November 07, 2020, 10:06:19 pm
content: Quote from: exe on November 07, 2020, 08:32:52 pmPower modules are isolated. PE could help because both Vout+ and Vout- have 10n to PE.

author: motozak
author_rank: Newbie
timestamp: November 13, 2020, 04:21:04 am
content: I am very interested with the EEZ DIB BB3 PSU, I want to build one but there is a problem with the MCU (STM32F769IIT6), this is very difficult to find in my areacan I replace it with another type like STM32F767IIT6 or STM32F767IGT6?

author: prasimix
author_rank: Unknown
timestamp: November 13, 2020, 08:16:20 am
content: I'm aware of current shortage of selected MCU (only Farnell have it on stock). Using another MCU is possible in theory if pinout is the same (don't know), but even that one have to create new .ioc file and rebuild a whole firmware for it. If you are not skilled in programming, I would not recommend it.I can also say that we do not plan to support any other MCU because we already have too much work to do to improve the firmware for the existing one.

author: exe
author_rank: Unknown
timestamp: November 13, 2020, 08:59:32 am
content: May be a solution could be to purchase an assembled mcu board separately (if they are available).

author: prasimix
author_rank: Unknown
timestamp: November 13, 2020, 09:00:20 am
content: ... will be, I believe soon

author: knapik
author_rank: Regular Contributor
timestamp: November 21, 2020, 09:53:13 am
content: Well, I didn't make an order from TME and had trouble finding the exact parts required for the ethernet jack. Thinking they were all identical, I found a replacement connector with a matching footprint and ended up spending a couple of days trying to figure out why 3.3V was shorted to groundHowever, I found (if you're willing to live without the integrated LEDs) that aproperreplacement can be found at Digikey with part number ARJ11B-MASAO-LU2. Weirdly enough, I can't find anything that that matches with the integrated LEDs apart from those 2 part numbers already mentioned in the BOM (and are available at TME only).

author: prasimix
author_rank: Unknown
timestamp: November 21, 2020, 11:54:45 am
content: Thanks for finding an alternative. LEDs are not really required as the patch cable goes to the rear panel also does not have LEDs. It seems that Mouser also offer it (but currently out of stock).

author: jonr678
author_rank: Newbie
timestamp: November 28, 2020, 03:01:04 am
content: I'm not really sure what ordering from TME to the US would be like so I was trying to avoid it. It forced me to dig up a number of alternative parts that were not available at any other vendor. Here's what I was able to find:RJ-45Pulse J0026D01BNL, has an identical pinout, LEDs, and magnetics configuration but instead of the bypass cap tied to the shield, it's tied to pin 4 & 5 (same as the Abricon part mentioned earlier). I was planning to simply jumper pins 4&5 to one of the shell tabs for ground.Yellow LED on the AUX PS board:Kingbright WP934AD/YDTHe dimensions aren't EXACT but should be close enough. Some at Digikey, a few at Mouser with more due mid December. I just realized that I never checked the polarity on this part but the LED isn't molded into the housing and should be easy to flip if it's wrong.DCP405 binding postsPomona 73099-0 - BlackPomona 73099-2 - RedThese are more expensive than the suggested part but probably easier to get in the US. I did find the suggested black part (FCR) at Newark but I didn't want to order 1 thing from Newark and still need a red one. I will likely just use the black one of these in place of the ground plug on the AUX power supply as well. If I feel like it, maybe I'll paint it green.PMB-1:PCB-MB-01 available Digikey and MouserI think this was mentioned in an earlier post.I have not found an alternative to the big heatsinks that are specified for the DCP405 (available only at TME) and I don't really have an idea how I would find one without diving through heatsink catalogs for hours. I have a couple of ideas that involve some fabrication but I haven't really chased it down any further. If someone can tell me that ordering from TME to the US isn't a terrible idea (I'd rather not spend 4-5 times what my order is for shipping) I suppose I'll just get them there.Jon

author: prasimix
author_rank: Unknown
timestamp: November 28, 2020, 07:15:36 am
content: Cannot say what is the situation with TME in the US, but I can say that in the EU it works simply flawlessly. They are fast, and it is possible to pay with PayPal.If there was any problem with them it is easily possible that there would already be a topic about it on this forum.Regarding the LED on the AUX-PS: you can always take any 3 mm LED and bend its pins yourself.

author: exe
author_rank: Unknown
timestamp: November 28, 2020, 10:56:39 am
content: There are a few people from the US who successfully ordered from tme. Like in this thread:https://www.eevblog.com/forum/buysellwanted/lfs-where-to-buy-brymen-867s-869s-with-shipping-to-usa/. I also found an old thread (from 2012) where things went south.I personally made 16 purchases from them over last four years. I have good experience with them so far, but I'm in Europe. I don't know how they handle customs and duty when sending to US. Otherwise, I wouldn't be worried about them.My only complains about them are:1) They don't deliver non-rohs stuff to my country (such as leaded solder)2) I had to contact support to change delivery address. There simply was no button to edit personal details. They redesigned the website recently, may this one is fixed already, idk.3) Adding potentially inflammable items (fluxes, aerosols, even if it's a 5ml syringe) requires changing of delivery method. They require ground delivery for that, and for me it's not straight forward how to make this change. I did trial-and-error changing delivery methods until the system accepted the order.4)They didn't display stock in searchthat was fixed, cool

author: jonr678
author_rank: Newbie
timestamp: December 05, 2020, 11:57:00 pm
content: Yeah, my main concern was shipping and duties costing as much as the parts I was ordering. I'm sure ordering from them in Europe is great, it's my not being the EU that makes me want to avoid it.

author: exe
author_rank: Unknown
timestamp: December 16, 2020, 10:46:45 pm
content: I started repairing my last dcp405. With this one, because of damaged pcb, I relocate components to the new pcb. I decided to experiment a little bit with soldering. I use lead-free solder paste and some fluxes that I rarely use. On pic my current progress with relocating parts. I started with smd parts, and remote through-hole components to have easier access. So far so good, but ultimate test, of course, is to power it on and load.

author: prasimix
author_rank: Unknown
timestamp: December 17, 2020, 07:04:59 am
content: If you are going to solder used parts I'd like to suggest to check bias pre-regulator output voltages first by removing FB1, FB2 and FB3.

author: Lion_Tamer
author_rank: Contributor
timestamp: January 31, 2021, 01:03:31 am
content: I am currently building my BB3 kit (as budget allows) and I am pretty close to getting it the chassis fully operational but have now hit a problem.The Aux power is built and seems to be working perfectly.The MCU is the module that is currently giving me grief. The only 2 parts that are not fitted to it are the encoder SW2 and the Speaker SP1 as they haven't arrived yet (I have also left out the battery), as far as I can tell neither of these would stop it working. I have programmed it via DFU with the firmware from github ("bb3-v1.5.dfu") and utility verifies it as successfully programmed. When I power it up I get nothing on the display, checking around with a scope I don't see any activity on the signal lines to the display and the back light is not activated, I have run the scope round a few places on the board and found the following:X4 Reset = this is line is pulled low every 450mS for about 30uSY1 (25MHz) = this seems to start running for about 350mS and then stops for 100mSIC6 (SDRAM) = I have gone down every pin and found the expected power/ground/activity on every pin except BA0 and BA1 which seem to be held low (I suspect that this may be correct behaviour)There is no activity on the I2C1 busI would guess that it is stuck in some form of reset loop but not sure where/what to try next as I am not sure what it checks before it activates the screen. I have also tried running the MCU on the bench off of a 5V power supply with and without the screen attached with no noticeable change.Here are some other notes of my experience which may or may not be useful to Dennis and/or others - Most of these are not big issues and I have not got any problem with sorting them out myself so you may take or leave as you wish:The screen mounting nuts were not done up - there was visible gaps between the nuts and the screen frame.4 of the 6 holes in the chassis front panel were not taped at all and 1 was poorly doneThe mean well mounting frame has one hole that has been over tapped so will need a nut and bolt or larger diameter screw.There was only 2 Power Module DC Input cables rather than the 3 there should have been"EEZ DIB MCU r2B4 BOM.pdf" - Line 5 - 1uF Capacitor - The RS part No provided is for a 100nF Capacitor"EEZ DIB MCU r2B4 BOM.pdf" - Line 28 - LCD1 Connector - RS Part No 178-9542 can be put here"EEZ DIB DCP405 r2B11 BOM.pdf" - Line 20 - 470nF Capacitor - The RS part No provided is for a 470pF CapacitorJem

author: prasimix
author_rank: Unknown
timestamp: January 31, 2021, 07:08:51 am
content: If reset is active every 450 ms that something is definitely very wrong, but it's hard to me from the distance to suggest anything since I didn't experience similar problem with my hand made modules (I assembled almost a dozen of it). Perhaps you should check very carefully SDRAM (IC6). Of course check if MCU (IC3) is properly assembled as well. Without proper connection with SDRAM firmware cannot continue and it is quite possible that internal watchdog initiate reset.

author: prasimix
author_rank: Unknown
timestamp: January 31, 2021, 07:54:16 am
content: Quote from: Lion_Tamer on January 31, 2021, 01:03:31 amBOMs updated onGitHub.

author: Lion_Tamer
author_rank: Contributor
timestamp: January 31, 2021, 11:48:03 am
content: Would I be right in thinking that the MCU only sends data to the display and doesn't read from it? That being the case I should be able to tell when I have fixed it without having to constantly reattach the display.

author: prasimix
author_rank: Unknown
timestamp: January 31, 2021, 12:11:42 pm
content: MCU cannot read anything from display. Firmware generates picture in SDRAM in frame buffer area. Therefore if SDRAM is not completely functional you cannot expect anything on the display neither firmware could continue. MCU can read only from touchscreen controller that is connected to resisitive touch panel glued on top of display. Ok, display and touch panel share the same 40-pin FFC connector but they are two separate parts. So lack of display cannot be the cause of 450 ms reset cycling.

author: Lion_Tamer
author_rank: Contributor
timestamp: January 31, 2021, 03:54:09 pm
content: Victory!After going round and round the processor and SDRAM checking all the solder joints and getting nowhere I checked it into the ultrasonic cleaner to remove any flux residue and then I was finally able (with the aid of a 60X loupe) to find the tiniest solder whisker that I have ever seen, it was a bit of a pain to clear it but it now boots.Jem

author: KeithMN
author_rank: Newbie
timestamp: February 04, 2021, 06:31:58 am
content: What's the best way to get a set of stencils for the Bare Boards Kit? Mainly, I'd like them for the MCU board and the DCP405s. Also, is there a way to get ahold of a blank module cover for the third DIB slot? Gonna hold off on the DCM220 for now.

author: prasimix
author_rank: Unknown
timestamp: February 04, 2021, 06:43:20 am
content: Hi, I never used stencils for this project but I believe that you can order them from JLCPCB or similar places. For blank module front panel you can contact me via PM.

author: Lion_Tamer
author_rank: Contributor
timestamp: February 07, 2021, 09:54:42 pm
content: Well after getting the chassis working last weekend I decided to spend today to start working on the 4 junk yard DCP405 modules that I bought and thought that I would put my findings so far below (this is the short version minus the rabbit holes) in case it is useful to others. please note that all voltages are with reference to the Gnd test pad on the module.Module 1:This module had several of the large electrolytic capacitors either knocked off or hanging loose so I started by re soldering all of them before i plugged it in and powered it up.The module was correctly recognized but every time I enabled the output it put out approx 40V (the display also showed that 40V was being put out) no matter what the set voltage was.I decided to turn the output on and off a couple of times to check that it was consistent behaviour, at this point R29 (Down-programmer Load Resistor) decided to let me know that it was unhappy by letting out the magic smoke followed by breaking in 2 and falling off of the module, during this time the output dropped to about 6.5V till the resistor fell off at which point it returned to 40V.I removed the Down-programmer Mosfet Q5 (it was short circuit) and the remains of R29 and because I don't currently have any suitable replacement resistors it was left disabled.Testing the PREG_OUT+ and POST_OUT+ rails I found 47.6V and the Base of Q3 and Q4 was at 46.9VWhen I tested the DAC (IC16) output at the test point "U" I found that it was working correctly. I then checked at the joint Anode junction of D12/13 where I found it was being pulled down to -1.7V which told me that the voltage control loop was attempting (but failing) to lower the output voltage to the correct value.After checking that Q9 was turning on I decided to swap Q8 with one from one of the other junk yard modules at which point the problem was cured.I still have to replace R29 to repair the Down-Programmer section before I can fully test the module but it now appears to be fixed and operating correctly.Module 2:Again I had to resolder the large electrolytic capacitors before I could power it up.The module was correctly recognized but would not output more than a few millivolts (as shown on the display) no matter what the set voltage.The PREG_OUT+ rail would not go above 4.72V.Test point U was setting correctly.The Anode junction of D12/13 was at 4.3V so again I knew that the voltage control loop was working and attempting to turn on Q8.After checking Q9 operation I decided to try changing Q8 at which point the module works correctly.I still need to glue the small heat sink onto both modules so can't load them down much yet but I have high hopes that both are fine. It took me a while to get my head around how the pre and post regulators work together.Maybe next weekend I will get the other 2 modules repaired once I have some replacement parts for those that I nicked (mainly Q8) from them to get the first 2 going.Also as a quick reference for those that are fault finding these modules here are some voltages for test point U as taken from a working (non calibrated) module.Set Voltage = Test Point U1V = 120mV10V = 680mV20V = 1.30V30V = 1.92VJem

author: exe
author_rank: Unknown
timestamp: February 15, 2021, 06:55:26 pm
content: I finished assembling the board. Learned a lot along the way. Unfortunately, it doesn't work yet. I set current limit to 40mA, and powered the board. It immediatelly started to consume all 40mA. The voltage clipped at 26V, but when I re-applied it again, it now is ~5V. Using thermal camera I see C5 is getting kinda hot (~40C according to my flir).I also applied input voltage in wrong polarity, so I guess I might caused additional damage.BTW, a two caps and a ferite bead fall apart while I reworked them. Not sure why (probably my soldering skills). Both caps cracked, and, afaik, were of the same value. Ferite bead looks like have a "cap" on the end. Was is a stress-relief cap or something?

author: prasimix
author_rank: Unknown
timestamp: February 15, 2021, 07:02:09 pm
content: I presume that is not a "junkyard" modules but new one built from the scratch. Reverse polarity on power input with current limited should not generate any problem as long as TVS on the input is mounted correctly. For start I'd remove all three ferrite beads and check if +/-5 V is present.

author: exe
author_rank: Unknown
timestamp: February 15, 2021, 07:37:55 pm
content: Well, it was a junkyard module. I transplanted parts to the new pcb. I replaced a few parts here and there that didn't survive my desoldering. Does this change anything?

author: prasimix
author_rank: Unknown
timestamp: February 15, 2021, 07:47:03 pm
content: Try to activate it step by step: first check bias power supply, then power pre-regulator, and then CV and CC sections.

author: prasimix
author_rank: Unknown
timestamp: February 16, 2021, 08:20:07 am
content: A short notice to all builders: since latest revisions are recently committed on GitHub, Crowd Supply versions are now available inhttps://github.com/eez-open/modular-psu/tree/master/previous%20designsin subfolders with(Crowd Supply edition)suffix.

author: exe
author_rank: Unknown
timestamp: February 16, 2021, 08:25:26 pm
content: I removed capacitors that I thought are shorted, but the problem remained. Unfortunately, what happened is I misinterpreted picture from the thermal camera. It superimposes image from IR camera with normal camera. At close distances there is a misalignment (trap for young players). So, in reality it was LTC3864 that heated up. I ordered a replacement IC.

author: prasimix
author_rank: Unknown
timestamp: April 08, 2021, 06:29:40 am
content: If someone is still interesting: only three pcs of BB3 Enclosure & Bare Boards kit left on Crowd Supply which is the last quantity since we will no longer offer that kit version.

author: DL8RI
author_rank: Regular Contributor
timestamp: April 10, 2021, 07:36:30 am
content: Following Text was written before the... erm... lockdown of the forum (I still could write it, but when I wanted to post, the board was nuked):Hi All,I'm a bit late to the party, had some other things occupying me (and had parts on back-order).Today I managed to do the assembly of my EEZBox with the cards I had so far.I'm missing both DCP405s. On them, I will start tomorrow.So far, no real Issues. Except procuring the parts was a bit of a nightmare.With the DCP220, I noticed, there is a reading <250mA if the current is low, is that a usual behaviour?I calibrated it, and voltage and current are otherwise of acceptable precision. Had both channels (separately) run on ~60W for some minutes and it did not burst into flames.In my package, I noticed today, one of the DC-Cables (MW PSU to card) is missing and I only have one of these green "push-in"-connectors.Could you provide me the mouser-number for the exact connectors used, that would save me quite some searching as there's a ton of variants?Other than that, it's a really nice kit. A lot of work, sure, but thanks to good documentation not really difficult.Since there were some comments regarding soldering before:I soldered all PCBs by hand and used 40Sn60Pb (0.5 mm wire). The ICs with a unreachable heatsink underneath were done on a hotplate with some hot air. Here, I pretinned the board before as I had no solder-paste on hand in that moment.

author: DL8RI
author_rank: Regular Contributor
timestamp: April 11, 2021, 02:04:07 pm
content: Okay, so. Now one of the 405s is working, Full load torture test has to wait, as the small heatsink is not glued yet, but calibration (incl. the 5A point) was successfully completed.The other one is 99% complete, except for the IC1, I ordered only one instead of two (and I skipped assembly of Q1 and the post-regulator Qs to test the +-5V first).I noticed one behaviour:When I use the DC405 with a high-impedance load (none or a R&S UIG), I can not set the voltage to zero. It stays at about 0,2V.If I load it with a bit of a higher impedance, it goes down.This happens only in the low-current range.Is this a normal phenomena, or should i go for hunting?

author: prasimix
author_rank: Unknown
timestamp: April 11, 2021, 03:27:25 pm
content: The notifications don’t seem to have recovered from the last disaster yet, so I’m a little late with the response:QuoteYes, that is already discussed somewhere (probably on Discord server), and that is known issue for 0V/0A inLowcurrent range (the same is valid forBestcurrent range).QuoteYes, DCM220 cannot display currents accurately below 250 mA, hence is added "<" for low or no current.QuoteThanks for mentioning the push-in connectors. Now I see that they were not listed in the MCU and DCP BOMs. You can find the part number at the bottom of the "Related parts and accessories" sectionhere.

author: DL8RI
author_rank: Regular Contributor
timestamp: April 15, 2021, 07:40:08 am
content: Thank you for the answers.The Molex-DC connectors your're using are this ones, right?Mouser 538-39-01-3022They are not mentioned in the BOMs, and I need to crimp one (and want to avoid iterations of ordering to mouser).

author: prasimix
author_rank: Unknown
timestamp: April 15, 2021, 08:13:27 am
content: That's right. It is actually mentioned in BOM but in another place:https://github.com/eez-open/modular-psu/blob/master/enclosure/EEZ%20BB3%20r1B1%20BOM.pdf

author: DL8RI
author_rank: Regular Contributor
timestamp: April 15, 2021, 08:18:58 am
content: Oh, that BOM, I must have missed. Thanks a lot.

author: prasimix
author_rank: Unknown
timestamp: September 16, 2021, 06:23:56 am
content: We have 9 pcs of STM32F769 used on MCU module for sale, if anyone is interested send us email on shop@envox.eu

author: rthorntn
author_rank: Frequent Contributor
timestamp: February 28, 2023, 03:11:53 am
content: Hi,Anyone out there have a spare working MCU board for sale?Thanks.Richard