I’m currently in the process of building the awesome Midibox SEQ using Wilba’s front panel PCB from SmashTV’s shop. I am using an STM32F core board. I have soldered the following on the front panel PCB:
All diodes
J1 connector
All 5 pin resistor networks
All IC sockets
All pushbuttons
Capacitors
I have not soldered ANY of the following:
Resistors
Rotary encoders
LEDs
Anything else I am missing?
I have two LCD modules connected to my core board (and they work fine), and the front panel PCB (to J8/9). Pressing any of the buttons does not do anything.
Things I have checked:
All diodes are in the right orientation
All ICs are in their sockets in the right orientation (U1-U6 are the 165, U7/8 are 595)
I can see a clock signal on J1 SC pin. I can see VCC and GND.
One important mistake that I made: I initially soldered the J1 connector in the wrong orientation (or the flat cable I used is different than the one that’s on the photo instructions thread). This resulted in U1 overheating and may have ruined it or anything else. After discovering this awful mistake I used wire patch cables to connect the core module and the PCB so I am fairly certain they are properly connected now (I can see a clock signal on SC, and measure ~5v between VS and VD).
Does anyone have an idea of what can be wrong? Here are some theories that I have but not sure if they make sense:
I ruined some or all the ICs - thankfully they are socketed so I will just order a bunch of new ones and try that next week.
I ruined something else - I doubt that because capacitors, switches and diodes are pretty resilient and I can’t see reversed connector being an issue
This thing does not work without the LED resistors (I doubt, but maybe I’m wrong? I couldn’t find a schema of the board online).
I have access to a 2 channel scope so I can look at signals if someone has an idea of what would be worth checking.
I also checked the resistor networks, they are properly placed. I used the buttons SmashTV sends in his parts kit, and they cannot be misaligned. I ordered new chips so I will just try that next week when they arrive.
Had the same problem once - with the 180° rotated cable. I doubt, you ruined your shift registers, mine got very hot and I did not realize it for a few minutes (drinking that coffee was more important! ;-)).
I therefore suspect sth else, but I might be wrong, ofc :-).
Suspection:
Make sure, that Serial IN and Serial OUT (SI/SO) lines are not accidentally swapped. This could still happen, if the cable is built wrong. You can test to swap these lines (nothing bad can happen).
A good test is to use a continuity tester / ohm meter to map the silkscreen printouts of J8/J9 with J1 on the SEQ CS.
A few other tips:
Check for voltages across the CS board. Every IC must be powered with 5V across its supply pins.
Enable the SEQ Button test mode in the MIOS Terminal.
Insert a few resistors and LEDs (no real need to solder), just add 9 220R Resistors at the center of the board around the center encoder slot and add just one LED above the first GP button - it should light up after booting.
Attach your scope with the probe to the serial lines and (and probe gnd to gnd). You should see high-speed pulsed signals on J2 of the CS PCB (it is a serial extension of the inputs from J1 to attach other hardware, like the TPD board).
