latigid on

BLM 16x16+X build guide

168 posts in this topic

53 minutes ago, Claire said:

Just a question really: why through hole diodes?

When building monome kits (the new ones, the slim, grid kid 128) I found the migration from through-hole diodes to SMT to be really very helpful on repetitive tasks (tin pad, heat pad, slide diode into pad, solder other pad: repeat). OK you trade the fiddlyness of small easy to incorrectly invert diodes but there is no bending cutting and board flipping and because of the low profile of SMT parts diodes can go on the silicone side easily enough if needed.

The idea from the start was to minimise the SMT and use commonly available parts where possible. The LEDs were different as they sit in a routed channel, but that was part of the choice for resistor networks in chip packages rather than discrete. Something like this would be a great investment:

THT are a cent each in quantity, more for SMT. MELF = mostly ends up lying on the floor, so you'd likely go for one of the SOD packages.

Looking at the design again, I think SMT would work on the rear side most of the time (disagree about the front side, you want that as flat as possible), but there are parts of the board where diodes bridge a layer. It's a complicated PCB and keeping one footprint simplifies the process. I don't think I'm prepared to redo the whole thing again because it's a lot of work and the risk would be on me not to propagate errors.

 

53 minutes ago, Claire said:


@latigid on are you going to make this board available again? I have my work cut out with a project at the moment but I'd be interested in getting back into grids at some point but monome is going in a direction that is a bit eurorack-centric for me and the max-msp/serialosc/computer side of things seems to be slipping a bit.

I can't do a big order like this without paying taxes. Especially as a foreigner in DE it's not straightforward to wade through all of the bureaucracy and set up a business. I know you've just signed up, but it seems over the last year or so a lot of "puff" has gone out of the forum. It's less desirable to go through all of that without an active community presence (I realise the chicken-egg analogy of supply and demand being mutually dependent).

I need to stick my finger in the wind so to speak and also check on my situation here. What I'd most like to see is a return to the motto of "Community Designed MIDI Devices" printed as part of the forum logo. 

 

53 minutes ago, Claire said:

It would be nice to see this branch out to other applications other than the SEQ, has it been used anywhere else that you know?

@Phatline makes good use of it in his Triggermatrix.

 

Best regards,
Andy

 

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Ok all good reasons. If a new build happens I'll hopefully be on it. I do think you are being a teensy hard towards SMD diodes (but yeah I had a tray of SMD LEDs go that way...ugh). They are just as common as through-hole and just as cheap from experience, but I'm weird and find SMD 1205 and 0805 to be easier than through hole... and so many parts are now in TSSOP over PDIP -- I'm probably in a minority like that...

When I get an Eagle file I usually look for ways to convert through hole parts into SMD, it helps make things very slim profile for Skiffs and so on and I can get bigger boards into Eagle's Freemium size (I really really must get a proper licence some day).

If you ever have a waiting list for boards I'll be get on it.

Thanks for the detailed response

Edited by Claire

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I too would like a PCB for this wonderful project, I hope it happens and I certainly appreciate all the work TK, Andy and others have done and are continuing to do for the Midibox system.

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Hello, TK, Andy and Others
I see that this magnificent project does not move any more. As many of us are waiting for the PCB and the case, how can we help to move the project forward

Pierre
 

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Don't worry, it should happen again someday... 

Best,
Andy

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Is it just PCB supply holding things up? Could the files be offered to Modular Addict like the MB-6582 and MBSEQ?

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cut that man some slack, if he says, there will be a new edition, then there will be one! :-)
(i can only imagine how much work running a bulk with a project that size really is - and there might always be other priorities like girls, football, work and babies in life! :-))

Many greets,
Peter

 

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Hehe Peter, don't spread rumours! :P

Best
Andy

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Sorry, not trying to get on anyone's back. Quite the opposite, thought maybe it would help to offload some of the work of doing a bulk order (which is a rough job).

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Posted (edited)

i am finishing my second BLM, and i have a problem:

horizontal Xtra row, the last four(most right) led pairs want show up (seeing with running light), also the buttons for it dont react -  what part could be the problem

i already replaced q33 and r45

-while soldering i replaced rn19, and lost some pads... which pad  is for the last 4 leds?

i also used a hot-air fanl, so maybe ic19 (next to rn19) could be faulty?

 

on vertical row led pair 5-8 (counted from below, over shift) only give me the left led (each led of the 4th block) - but buttons are working

 

where to start debuging? thx for help.

Edited by Phatline

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Posted (edited)

21 minutes ago, Phatline said:

horizontal Xtra row, the last four(most right) led pairs want show up (seeing with running light), also the buttons for it dont react -  what part could be the problem

i already replaced q33 and r45

-while soldering i replaced rn19, and lost some pads... which pad  is for the last 4 leds?

i also used a hot-air fanl, so maybe ic19 (next to rn19) could be faulty?

 

This current sink runs to pin 16 of RN18 

You could try to bridge the current sink and pin 15 of IC18 with a 1k resistor as shown (actually to the SMD pads):

5aae3eedb7c4f_currentsink180318.thumb.PN

 

21 minutes ago, Phatline said:

on vertical row led pair 5-8 (counted from below, over shift) only give me the left led (each led of the 4th block) - but buttons are working

 

The extra column LEDs are also connected to the extra row. If right LEDs fail to light, is this also true for every third LED (right-hand LED) on the extra row? (Normally I would count the extra column LEDs from the top; from your meaning I am guessing this is the third set of four using this counting system.)

These LEDs are all connected to RN19, pin 10. Pin 7 of RN19 then connects to IC18 IC19, pin 5.

 

Best,
Andy

 

 

Edited by latigid on

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first to the horizontally:

  it turned out that the left leg (top viewof part) of q33 is somehow  grounded....

i removed r45, q33, 1n4148 and RN18, and its still groundet > i found out that RN18  had a short on the pcb between ground and the pin where you draw the connected the yellow airwire (rn18 pin 9 when i count that ics right...), i scratched the chopper away with a knife:rn18-short.thumb.jpg.acf3e8de71f37adaf95

-well that block is working now except one LED - the missing led  (the led itself is working, i removed it to go shure ), on the common side its all right but on the "T"op side i have 56Ohm to ground, while on all other LEDs have 5Mohm to ground...  it is connected to RN19, which is a 56 ohm network, so it has to be groundet somewhere on the other side of the network... the network where i lost some pads in the past, ok desolder it with hot air fan....

rn19-overheated-pads.thumb.jpg.5b151d954

ok what i see is not very good: Pin 7 is groundet, and removed from pcb (the chopper pad has moved) ok clean up and connect it directly to ic19 Pin 5,

also Pin 9 looking bad because it is loosing pcb contact... so better also remove the pad, and make a airwire..., but in order to solder it on this tiny tiny tiny thruhole connector, i have scrath a new "via" with the ground plan around it... in  order to mechanicly connect the wire

rn19-new-wire.thumb.jpg.ffacd9dd038d4d07

 

conclusio:RN19 i messed up by trying to desolder it leg by leg... > always desolder chips with Hot AIR FANs

conclusio: RN18 make bigger traces around Ground Plane and Signal Pathes... a single tip with the soldering iron can mechanical withen  the copper to make a ground short....

 

its all working now!

 

 

 

 

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Posted (edited)

Just now, Phatline said:

its all working now!

This is the main thing. Well done!

Your second photo represents the problem nicely: sub-optimal registration between the soldermask and copper plane. This, along with a) white soldermask that typically scratches easily and b) a 0V plane with tight clearance to the signal pads, can lead to these annoying ground shorts. I'm sorry for the hassle. This was a few years ago now, nowadays I increase the clearance :).

One tip: you could get some enamelled copper wire for these little patch jobs. You could even salvage an old transformer and unwind the coil. To make a joint, cut the wire to size and melt through the plastic insulation to form a good joint. (see also Reichelt: FAEDELSTIFT WW)

 

Edited by latigid on

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thx.

ahh your right, i have such copper wire @ home, didnet use it that much, so i didnt think about that solution, that would be thin enough to connect it directly to the thruhole connector...

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Posted (edited)

i have made a stop motion video,

about the soldering the pcb... i have cut it to 6 minutes, so not all stuffed parts are shown, but most of part-groups

the music is drumside made with the BLM:

 

 

haveing more stop motion videos about lre2x8, core, din, mf-ng, and others... coming in future online (when having time to cut and deciding which music track under it...) (made with a lumix g85)

Edited by Phatline

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Another “please let me know when Board’s are available again” reply.

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Will do. Current focus is on the SEQ v4+, LoopA etc.

Best,
Andy

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