Machine Drum MK1 Encoder Schematic REPAIR HELP / Spares

[stevencrichton]

So I have a Mk1, that I decided to replace all the encoders on. Using a Vacuum desoldering station I dutifully took each one off with care, but something has happened.

When back together up/Down page 3 of the synth and other buttons are non functional and tempo creeps up. Plus the 3rd row from the screen encoders are useless and jump about.

The MD is now with a tech who has diagnosed an issue with the UART Multiplexer readout on the 5th Column of the 8 in the diode switch matrix.

I have tried and had no luck contacting Elektron to attempt to get a schematic of just this area.

The options are:

1: Has anyone experienced this same issue and has a solution?
2: Does anyone have a good picture of the top of the MK1 non UW machinedrum Control PCB with no encoders installed to see the traces.
3: Does someone have an actual contact in Elektron to ask to sign an NDA to get a schematic to resolve this? ( @Ess, @nedavine any leads you guys could PM would be appreciated )
4: Does someone have a top MK1 Machinedrum non UW operational PCB I can purchase?

I’m literally begging on my knees to ensure I am not forced to scrap the thing. I’ve already got the expensive Torodial PSU etc.

All help really appreciated.

Steve

[Claid]

If anyone can help @stevencrichton I would be hugely appreciative. He’s a good friend and I am familiar with this Machinedrum model, as it was once mine. Feeling pretty bummed out that it’s no longer working.

[orion]

Did you reset the unit after replacing encoders? Did you run test mode? May i ask which encoders you replaced the old encoders with?

[orion]

I think the correct ones are the bourns PEC16-4020F-S0024

[stevencrichton]

I don’t have the unit here to check the code on the encoders, but they were sold as the correct ones and the repair tech it is is with confirmed they are correct too. The number of steps for the striping etc.

Test modes and resets all yes been tested.

It is a confirmed issue causing the multiplex row 5 does not ground out. On a scope reading the signals the pic gets the 5th row gives a downward saw type wave, Vs the required binary square.

This is the same over the buttons and encoders on that like group.

[infekted]

type in PEC16 in search box. quite a few threads detailing what and how it should be done.
in red eye topic i recall posting some pcb pictures.

[stevencrichton]

Unfortunately it’s not the encoders themselves. I am on the 2nd set to rule out part failures.

Will read through a few of them to find the PCB pics.

Thanks

[stevencrichton]

Alas nothing in a PEC16 search for the top of the MD mk1 PCB with them removed.

[infekted]

my bad, havent read your OP in detail. your tech is probably right. multiplexer might be an issue.

have you tried replacing internal battery? sometimes discharged battery causes similar issues.

schematics? havent come across over all these years.

from what you described another option is that there is a short somewhere (where you did soldering work).

if i were to troubleshoot it, I would desolder all the components you installed one by one to identify location causing the trouble. another approach is to desloder them all, check for continuity between enc pins/holes and the mux. obviously it may be a all wrong approach but it is how i would start.

[waftlord]

@stevencrichton

Does someone have a top MK1 Machinedrum non UW operational PCB I can purchase?

Have you a pic of yours top and under post the encoder swap? Might be easier to see if anyone can spot a cut trace or damage caused to isolate.

If something got too hot obvs harder to see

[orion]

If you have in fact narrowed it down to the multiplexer maybe you can swap it out. I can open my mk2 uw for part number if youd like. Im not sure how different the pcbs are on the mk1 vs the mk2 tho.

[stevencrichton]

At the moment it is trying to find the run of the traces due to the large ground plane.

The tech thinks the Uart is ok, but there is a slim possibility the pic located to the right of the screen that transmits on the serial bus may have a pull down resistor too.

The first port of call is a picture of a non populated encoder section from a mk1 . To avoid total desoldering of the encoders, as it’s very difficult not to trash them due to the way the support legs connect. A heat pad may cause other damage.

My hope is out there there is a schematic of this area that Elektron has ( it’s a diode matrix hardly a trade secret. ) or someone has a photo of their board top without encoders to see what traces run under the first 5 encoders.

Thanks for the offer with the mk2. @Claid has offered to even send his to work from, but the mk2 uses a 2007 revision PCB Vs a 2001. So there must be a few changes to account for the differences in the page button and how it does the count of 4 Vs 2 and transmits this on the serial bus to the motherboard…

The most frustrating thing is you can till turn it on hit play and everything works… just the only option is using that one pattern at the tempo it is at and loving with it for eternity !

My other real hope is someone on the forum has a dead mk1 that has a operational top PCB but wrecked mobo, that would sell me it. Or … I sell it and the new torodial PCB. My tech Jamie says it can be fixed, just I don’t have the disposable income I once did with two kids to let his time keep running on.

[orion]

Man, i highly doubt you’ll find a schematic, they’ve kept that secret really tight. The mk1 has the blue pcb right?

courtesy of plasmamusic.com

[stevencrichton]

Correct.

Trying to get a good image of what is under the first 5 or last 2 encoders.

I am sure there could be a call with an NDA to sign. They don’t repair them, but have in the past so there must be service manuals produced. Also the US office had repairs done on site.

My desire to leak or clone a machinedrum schematic is as about as close to 0 as any human can muster! There’s many better things I can use my time for… like playing a repaired machinedrum

[Bitsnbobs]

Brave move

[orion]

For good measure i would reflow the solder joints that go between the ui pcb and the cpu pcb. Many a known issue stem from old solder. Secondly, as you probably already know there arent any components underneath the ui pcb just a bunch of via’s. This pic is crappy but i might send you some mk2 pics just in case.

[stevencrichton]

Thanks, really appreciated.

Unfortunately they have already been reflowed. The jack board was also rebuilt recently too.

The mk2 is a lot nicer inside! The mk1 has a really nasty jack to motherboard stack header that requires the bottom boards to both be disconnected from the case. Also the reason for it’s case height.

I’ve opened another ticket with Elektron. The last was following up on the parts I ordered for it. So all I can do is wait.

[stevencrichton]

This is the one that frustrates me as I never took one before I placed the new encoders!

I have a clean picture of the rear. Alas not under them.

[stevencrichton]

All the surrounding diodes, resistors and various components have been reflowed and tested where appropriate too.

I have pretty much mentally resigned myself to having it as an ornament to be honest. Elektron have a bad reputation, judging by the other threads, for support with these. I doubt anything will change that.

[orion]

The uart multiplexer that your technician mentioned, can we get the part number and look for the schematic for that? May give you a hint.

Also, and thanks for being patient with my obvious questions but you never know, have you reflashed the firmware and what firmware you on?