MK-312 PCB manufacture

I’m still getting Failure 20 every time I turn it on :frowning: I’ve replaced all the mosfets and tried a different ATMEGA chip in case that was the problem but still get the same error. Does anyone have any ideas what I could try?

If that offer of PCBs is still open @voncosel then I would definitely be interested in taking a couple of sets off your hands. If I could figure out where the button is to send you a PM I would (I’m probably just being blind)

I’ve been looking at this project for some time now and finally decided to make an account since I finally bought the PCBs. Figured it’s worth it for me and everyone else to get involved and post. Anyways I’ve seen a few other posts like yours AVA around the forums about buying the boards and didn’t see much talk about people actually shipping/receiving them or contact info for people that have them. I don’t know if that was discussed in PM’s but I didn’t see it on the forum and now have 4 extra pairs of boards (V1.2 Front Panel and Main boards) if you(AVA), or anyone else is interested. I ordered them today so should have them in a little over a week. The main board is in green, the front board is in black/no-lead. I’m in the US but will ship anywhere. The best way to contact me is or you can PM me.

Thanks for stepping up on this!

I believe users of this forum have normally been just discussing shipping informally in PMs. I haven’t had any boards in my possession in months because I’m so busy with software work. I’ve poked at ways to formalize this trade too but once just tend to run out of steam pretty quick.

Ideally if someone knew how many people were putting in the effort to figure out how to build this themselves. Like being able to see the frequency/volume people access the BOM links and github repos they could do a little market research and determine if its worth one person buying say, the BOM X10 and selling the parts as a “kit” or package. There would be some significant cost savings for anyone buying that rather than all the parts themselves, that could allow the seller to profit some and make it worth their while. They could still probably offer the package at a lower cost when getting some take home pay then everyone buying individually. Prices really start to drop when you start buying 10-50 units at a time, they almost halve.

Thanks for the offer @Hydrogen but I already got my boards off of the lovely @voncosel

blush Thank you :smiley:

They arrived and I had the sudden realisation that although I had seen the diagrams, and had a peek inside an already built box, that bloody hell those gaps are tiny and I’m going to need a smaller soldering tip!

Hello, I’m also going to build the MK-312BT. But I have a few questions I will try to find answers to.
Is there any important difference between PCB boards 1.2 and 1.3?
Does anyone currently have one set of boards available at a reasonable price and reasonable transportation? (I’m from Central Europe. Transportation, for example from the US, probably will not be the cheapest.)

On the other questions I will ask when they come up with a number of (unclear about firmware and software)

Thanks. Zafphod.

@voncosel may still have some?

Thank you, however, my question is no longer up to date. I decided to order a set of 1.3b boards and front panels in China. Then I will have some extra available.

I know in electronics, it’s one of my hobbies and I can give someone some advice or help. I have a lot of knowledge and a well-equipped workshop. I can program microprocessors with a parallel programmer. Just my English is bad, so sometimes I do not understand some information.

Hi. Does anyone in UK/Europe have a spare set of PCB’s that I can buy? If making payment is awkward, I am willing to trade other parts (LCD, transformers etc) in exchange.

Thanks, Pete

I still have some PCB kits available in the Czech Republic. This is version 1.3b. But I can not guarantee its functionality. Unfortunately, I can not get the whole thing up and running. The power-on device still reports “Failure 20”. I can not determine whether there is a PCB, component or firmware error (or between a chair and a keyboard). I do not want to make the board available until I’m sure it’s not the source of errors.
I deal with it for about a week and I can not figure it out. If you do not mind waiting until the problem is solved, if I ever solve it.

I’ll try to direct some of the other mk312 people here to see if anyone can nail down the issue.

For Failure 20, have you checked that the direction of the MOSFETs is correct? We’ve had people put them in backwards before because the silk screen isn’t real clear.

Yep, I still have boards. Just contact me.

Yes I checked the MOSFET transistors and they are placed correctly.
I allowed myself to create a new topic to solve my problem in one place:

Thank you, for your valuable suggestions.

Hello @voncosel, is that offer with some set of the PCBs still on? I’d like to have some, if you have still some unused let me know. Thanks :slight_smile:

Even though you’ve asked nearly half a year ago: AVRs offer quite a few traps for young players. One of them is that generally memory addresses aren’t for bytes, but for words. In this case this means that the bootloader code is (expected) at word adress 0x1F00, thus at byte adress 0x3E00.

Which makes sense, as the bootloader code has to be a block at the end of the memory, which gets protected from being overwritten while the micro is running.

The official update as well as the selfbuilt frankenfirmware seem to end at 0x3DFF, the two prebuilt files seem to have gobbledygook at 0x3E00, that can’t be decoded as an opcode, resulting in an exception/halt.

edit: scratch that last part. AVRs seem to ignore malformed opcodes. still the part after 0x3E00 doesnt make much sense…

Hi Voncosel

I’ve been following this project for a little while with great interest. I have most of the parts together and have my AVR programmed ready :slight_smile:

I’d be extremely grateful if you could sell me a set of PCBs. I’m not sure how to PM you

Thank you so much