recuyBOY Build Experience for Eurorack

Notes from trying to build a recurBOY with a Eurorack PCB front panel:
Original project by @cyberboy666
Front panel PCB by @BastienL

  1. @BastienL’s current revision of the front panel PCB has an issue with the location of the CV jacks. They are spaced too closely together on the panel and don’t line up with the jacks on the PCB. They can be convinced to kinda line up if they are tilted slightly when soldering.

  2. There doesn’t appear to be a path to ground for the ground side of the composite jack. I did a bodge wire from a ground pin on the Eurorack power connector to the sleeve of the RCA jack and composite video started working.

  3. Having the Eurorack power socket on the front of the board makes the PCB front panel impossible to properly seat. The Eurorack power socket should be on the back of the board if using with a Eurorack-compatible front panel. :slight_smile:

  4. The orientation of the Eurorack power connector is overlooked in the build documentation. It should be oriented with the ‘key’ of the connector facing the SELECT button.

  5. The screen just sorta floats freely on its ribbon cable. Not opportune for long term use. I added very small strips of double-sided tape on the extreme edges of the bottom of the display itself to keep it from flopping around. Don’t put any tape on the back of the display as it can interfere with the light pipe for the backlight.

  6. It would be great if the display board was socketed so it could be removed and replaced without desoldering or if a repair needs to be made to areas of the PCB hidden by the display.

  7. The RaspPi itself is mounted VERY high on the back of the unit. It would be better if this were mounted lower, closer to the center of the board. This just makes life easier with most Eurorack cases and allows the opportunity to easily jump the HDMI and/or USB to a front panel breakout using short breakout panel-mount cables. For desktop use, this isn’t an issue.

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hii @bsom - thanks for all the notes ! its really helpful.

ah yes - you must have downloaded an untested version of the gerbers - this is a good reminder for me to start using the release notes and feature branches more on github for these revisions - i usually keep my WIP projects private until they are working so figure that no1 will be using em until bugs are fixed, but in this case i introduced this error while fixing another doh. anyway latest version of pcb is v0_7_1 and this is tested :ok:

agreed! most eurorack modules connect power on the back of the pcb

this is a good point ur not the first person to point this out to me - will def update the silkscreen for next batch and adding it to the documentation is good idea also - all docs are just text on github - feel free to add anything you thing would be useful - the more the better with these things i think !

im not sure exactly what you mean by this one ? the lastest version of pcb atleast has 4 mounting holes that you could connect to the four corners of the screen-board if you wanted to. although i usually dont bother - just connecting the header pins to the board and putting a small amount of foam between the screen and the pcb to give a little support works well enough…

yea this is a good idea - i have some recurboys with socketed screens exactly like this ! you could too - just means the screen is quite a bit higher from the pcb. but if u ok with this! i too have been caught out trying to make repairs under the screen. now i just have a desoldering pump so dont even bother with ic sockets most of the time tbh…

yeah i get what you mean - obvs the position of the pi on the board is made so you can access it from behind in desktop form. this is an example where having a different revision of pcb for eurorack version makes sense to me. also other design choices like position of the jacks etc would be different if designing for euro (also would go for smaller HP lol)

its my plan eventually to do eurorack revisions of all my projects (and for these use mainly smd parts for smaller form-factors / since euro-diyers usually are comfortable with this)

if you would like to help me with this / have any design suggestions im very open to it !

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@cyberboy666
I’d love to be involved in the design/testing/etc. of a ‘proper’ Eurorack version of the recurBOY. I’m working on some of my own modules as well but I’m still currently in the component identification stage. I’ll be doing some prototyping/breadboarding soon.

My comment about the screen floating might be particular to the lot of screens I received. They are connected to their carrier board only by their ribbon cable. There is no other mechanical connection between the display panel itself and its blue PCB carrier board. I’ve had this happen with cheap Chinese displays before where they don’t do any kind of bonding to the PCB.

Your point about putting something between the board and the display carrier board does offer some extra stability as well.

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As pointed out by @cyberboy666 in another thread, the Eurorack connector can be put on the back, as long as you make sure the key is facing the closest edge of the board. I’m an idiot.

Oh! The one on the Github is v0_6. :slight_smile:

doh ! ok that explains it lol. i pushed up the latest version im working with now so should be up to date.

iv been meaning to set up automatic jobs using github-actions to export gerber files from kicad and update release numbers and all that stuff to make keeping track of this stuff across multiple projects a bit more manageable … but everything in good time lol