XT MIDI problem…

…. so i wanted to do a nice 80ies style Baseline with my XT but it didn’t respond to MIDI anymore.
I took it to the workbench, all connections (MIDIconnector PIN4 > PIN 2 shows nice 220E from R16, MIDIconnector Pin 5 > Pin 3 of 137 shows 0 Ohms, Pin 6 shows 0 Ohms to Pin 14 of the ATMega and 7.4k to GND) are good but i resoldered them anyways. I also changed the 137 but all 4 showed the same behavior.
I can nicely scope the MIDI Signal pulling 5V to 2V on Pin 3 and 4,5V on Pun 2 of the 137 - but nothing on the Ouput Pin 6. MIDI? No can do.

Any Ideas? I have a severe Hall and Oates Attack and NEEEEEEED a SMR-4 Shruthi and this is currently my only one.

Try removing the microcontroller and check pin 6 again (in case for some reason the UART pin is pulled down).

Check that pin 5 is continuous with ground.

Sometimes i take things apart that is not working and i can’t find it at all. It happens that in the end it turns out to be something simple like a midi channel setting. As a DIY you can sometimes take the wrong route to solve a problem…

MIDI Settings - Check
Pin5 > GND - Check
Scope Pin6 without MCU > Everything works. Guess my MCU is flaky……

Guess its time to learn how to flash ATMegas, finally