SEQ v4+ Troubleshooting

dcam

I found the Engineer solder sucker I had, which was the key to removing the solder on the switch pins. Worked like magic. Reflowed T14 and put it back together. Destroyed two switches by pin trauma. Everything works! Phew

latigid on

Well done!

Jan

I’m hopping treads🙂 So after completing my LoopA I’ve decided to check in on my Seq V4. I’ve started half a year ago almost building them parallel and then life happened.
I remember testing the boards together and they were functioning ok, except for 2 LEDs.
Today, after 6 months, I’ve tested the LEDs with a multimeter and there are still just 2 to replace.
However if I connect the boards and run the test seq, all Leds flicker random for 5 seconds and then nothing happens… So here we go again 😅
Only connecting the core and the JA pcb with mios is ok, then I get the expected feedback from the JA.
Connecting LH and RH boards then results in hectic LED behaviour. So I will check all the ICs and replace the 2 LEDs, hoping that this will fix the issue, but I thought it made sense to write a message since that worked out so well last time. Is it short circuiting or could you point me into a direction? Cables are ok btw.
Cheers

latigid on

Did you mean fluxtest.ngr to test the LEDs? First you have to load the respective seq_l or _r. Definitely replace the faulty LEDs first in case they cause issues.

You could try to connect just one lemec board at a time to narrow down the fault. You could even connect the _r board to JA, but you would have to adjust the matrix addressing in the .ngc file.

Please upload clear photos of your boards for checking.

Best,
Andy

Jan

latigid on Hi Andy,
yes this was after using load seq_l. I’ll replace the LEDs ( both have a dead red channel), check the soldering and the content of the SDcard and will take pictures.
Thanks for the quick reply!

Jan

Jan 2 new LEDs and checked ICs. tesing later this evening

latigid on

Maybe IC5 has some shorted pins? In general you could reflow most IC joints to try to wet the solder to the PCB.

Jan

latigid on I think / hope thats just the lens distortion, I went over all the ICs, but have a close look when I’m home

Jan

its no masterpiece, but it’ll do😊

latigid on

Beautiful!

From the error description I can’t offer much, but maybe also check the LEDs in the MEC switches.
A classic would be if the resistor networks were soldered the wrong way around?
Does the _l board work if disconnected from _r?
Do the DIN inputs register in debug mode when the chaos happens?

Jan

It gets stranger, connecting evrything and running load seq_r, I get this weird christmas tree

Jan

the Ja board is lit but no action possible

Jan

however, if I run load seq_l, everything goes dark and almost all buttons work, light up and give feedback in mios.

Jan

I did only correct the RH board now. Ill do the same with LH soon and Ill give an update.

Jan

interesting, when loading seq_l, I can test the led matrix. with load seq_r it does affects the LH board like it does the the matrix, but horizontally🤔

Jan

Ill clean up the LH board and the JA board. Of course I was a bit to fast when building this 6 monts ago, did not follow the great building and testing tips in detail, lesson learned. And now Im learning about debugging😁

latigid on

The ordering of the boards and the particular .ngc file used will determine whether the matrices are properly addressed, or not. The RH board has three extra shift registers before the ones used for the DIN/DOUT matrices, so it won’t work to connect this to JA or the Core directly, unless you specifically change the matrix addressing. seq_r needs the JA board on the right (at the end of the chain).

Jan

latigid on I was suspecting this. So core to LH to RH to JA?

Jan

great! So with that out of the way there are only a few fixes left. LH has no led Action at 4 and 8 and no feedback at all on switch 9. RH has no feedback at all on 1 and15. since all leds are tested I suspect either bad soldering on the switches or reflow needs on ICs. Would be great ifyou could help me by pointing out the ICs connected to these switches?

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