latigid on

My apologies, that would be R14/R15 to IC4. Also check if any of R9-R16 are shorted to the adjacent resistor (the pins closer to the 595 would also indicate shorts on the IC pins).

Find a spot to clip your 0V lead e.g. the middle pin of the slide switch on the USB board, or solder a wire to the middle pin of the power headers there. Then just go through point to point, measure on the chips, the RJs etc. BTW, does fluxtest.NGR run properly?

Just to ask the obvious: are your resistor networks soldered on the right way? As you have a working lemec_L board, you can probe around for voltages and see where things differ. The parts that drive the fourth column of LEDs are: Matrix column RJ4/ RJ8, T15/16 (front side), R24/R25, IC4 pins 1/15. If the rest of the LEDs in the rows work, then there is no issue with the sink sides of the matrix.

Not easy to debug sorry... Basically there is no reason that you should get matrix DIN toggle events when rotating an encoder. There might be some sort of unintentional short between the boards (e.g. from a diode and you push the encoder button?). IC3 is the shift register responsible for the input side of the matrix, so maybe run the hot air around there or consider replacing that chip? The associated pull up/RN is right next to it

For example at Schaeffer (Front Panel Express): You would need to design a stepped window but it can be done! Maybe there is a design file around. Another way is just to use a thin sheet of whatever colour, either with or without a clear window. But if your panel is thick, a nice window looks subjectively better.

What output do you get from MIOS Studio with "set debug on"? The encoders are directly connected to 165 inputs, so IC4 is not involved here. Looks like there are a lot of blobs around IC3? Encoder pins connect to Plate J1, pins 8 and 9, if that helps. The encoder shouldn't hit anything below it, but you could try to slip a piece of card in between the boards to rule out unintentional short circuits. R13 does go to pin 3 of that IC. But make sure that it doesn't connect anywhere else.

You could use a white OLED (or LCD...) and a red acrylic screen protector.

That's right! Not sure exactly what your issue is here, but if you've narrowed it down to pin 13, IC5, you could bodge wire it to pin 3 on J5? Pin 1 of the connector has a square pad.

Clean work, you're doing great! That is a via that brings the SR signal to the transistor.

Thanks, it works. Can't see anything obvious. You can check the components I mentioned before. It could also be a too-long resistor leg, also on RJs? Before desoldering all of the switches, you might try to remove those resistors.

What I meant was to desolder a potential bridge there. Generally you don't want the output shorted to the power supply. But a constant voltage here would mean that the transistor base was always in the high state and not able to switch as required with the 595 pulses. I guess that's the case... light|shields and keycaps can stay on!

I could not see your picture of the soldering As the behaviour is common to a column (two columns, but they are only separated by RJ4/8) it is probably caused by 1. Wrong transistor type or otherwise an error with T16. Yep, that's on the top side of lemec_L! 2. The pin driving T16, so R16 and IC4, pin 15. With luck you just have a solder bridge to +5V (pin 16). Good luck!

Nice! Just be certain to solder the LED anode in the encircled pin, maybe test before soldering. It sucks to remove them if they are the wrong way around! But you probably already know this joy from the JA PCB.

Also a good catch, I had forgotten about that! There is not much risk in soldering in the MEC switches. It is only the Matias switches that you really want to be sure about because once they go in you have to desolder all of them to get to the inside of the PCB stacks (BC808s).

The switches SW17/18/20 won't work in the matrix unless this is bridged, actually done by the switch SW19 itself. Try to insert a MEC switch here. Sometimes it will work without soldering, sometimes you need to solder it in (or otherwise bridge it) to get a signal.

The 3M headers seemed to be easy to source and typically had good stock. It is also less effort to keep track of one part series. The 6mm "standard" single-row header might work (see above post) but the extra fractions of a mm help. That is why the 8.08mm part was ordered. Feel free to stick with 8mm. The same TE part on Mouser/Digikey is discontinued. Remember that the TE part you found has a plastic base height of 2.8mm, whereas the 3M one is "only" 2.54. So already there is a difference of 1mm.

There are two types of SMT resistor networks in the SEQ v4+. The bussed one on the JA board and two isolated on lemec_R to serve as current limiting for the activity matrix. Just use the product page to make sure you're ordering 8x resistors in a 16-pin package. If there are 15 resistors, that's the bussed one. (Seems like your RS part is good.) (There are also bussed THT arrays on lemec boards) For the pin headers, even normal length ones could work but they tend not to make good enough contact. Adding up the thicknesses: connector 5mm PCB 1.6mm inter-PCB spacing 3mm - plastic thickness 2.8mm 6.8mm of pin So I would suggest 826630, or actually 826935 as it matches the tin plating better. The 8mm one that you found would probably still work, just be aware that if it sticks through the header too much, it might contact the case.

I just hope that it wasn't 3x BAT54 on top of each transistor ;-) This approach works best I found when the solder has burned through its flux. If it's too hard, you could consider a fleck of copper tape or a strand of wire.

For v1.3_R Omit: IC6 (74HC123) C6 (or leave it in, no difference) C7 (top side) R17 (top side) Stuff: R26 (1-10k) or bridge it.

You will probably get bad ghosting without the BAT54s. Short of ordering a new board, just "stack" the BAT54s 1:1 on top of the BC818s, so with the text still facing up for both transistor and diode. Please stuff R17 (any value up to 10k) or simply bridge it. C6 and the nearby diode can be left unpopulated.

Awesome work!

No need to replace that pad, pin 1 does not connect to anything. Best, Andy

Yup, that's a common one! Actually Peter shows you the Mouser part number in the video but of course it is not 100% obvious and the part numbers are fairly similar. If you used leaded solder, you should be able to remove it easily. Flux can help but it is not 100% necessary. Normally I try for about 300°C and a relatively high airflow for this. If you need higher temperature it will probably be okay for the RN, but you'll need to take care of the other chips, MEC switches and encoder. When removing the chip, you might need to wiggle it to get the solder moving. When I do it, I always try to slide the chip laterally along the leads i.e. towards/along the long sides of the pads. This tends to keep the PCB pads intact and doesn't bend the chip leads, hopefully also the leads don't get too messy with solder blobs. When done, if necessary clean up the PCB pads with flux/braid to make the surface flat again. If necessary do the same with the chip. If it's not possible to easily get things flat, you can add flux and use the reflow hot air station again. Good luck!

You can get plugs of this form that have solder pins, but maybe you want to hack one together with a normal IDC (ribbon) plug? Take an IDC and remove the crimping part, then bridge all of the pins required, except leave the supply voltage (or 0V) floating to avoid shorting the power supply. Or take a ribbon cable and do the same? Just leave one conductor free.

Nice track!