Teensy 4.1 more sensitive to voltage spikes?

[qwazzerman]

Hi all, I have a setup that uses a Teensy as a DAQ to control some relays and read a few sensors. It previously worked with Teensy 3.6 with little issue. Since Teensy 3.6 was discontinued I have switched to 4.1, but am having issues with connectivity and Teensys no longer responding (presumably fried, although no obvious signs of failure). In moving to 4.1 I did redesign the circuit board it attaches to, but with all the same circuits and components as before. It makes me wonder if I've set the circuit up wrong or something. The setup uses a 24V power supply, a 12V power supply, and USB power for the Teensy itself. None of the 12V or 24V supplies ever reach the Teensy directly (in theory), but the 12V circuit and the Teensy share a common ground.
Here's a brief overview of the setup: Teensy with audio board connects to a custom PCB. Two pins control optorelays: one relay powers a 24V, 1.15W solenoid, with that ground isolated from the rest of the circuit. The other relay triggers a 12V LED light, also isolated from the rest of the circuit. On the common-ground side, I have an amplifier circuit (LM386) that runs on 12V power and takes the output of the audio board and sends it to a 3.5mm TRS jack. There are also two low-draw LEDs that are powered directly from the Teensy pins, and two optoelectronic slot sensors (IR LED/phototransistor pairs). The IR LEDs are powered by the 12V supply, but the power to the phototransistors comes from the Teensy's own 3.3V pin.
I've attached a simplified schematic of the setup, as well as a full circuit diagram of the 4.1 setup (note there's an extra solenoid in the diagram but it's not used). Is there something obvious that I've done wrong here, voltage-wise? I realize it's a complicated setup so I appreciate any advice.

 

[jmarsh]

I would be suspecting the LEDs because the resistors limiting current to them (R_TRL_LED and R_RESP_LED) are so low - the pins are only rated for around 4ma, so unless those LEDs have a large voltage drop there will be significant current going through those resistors.

 

[MarkT]

Perhaps a photo of the layout would be useful?

 

[qwazzerman]

I would be suspecting the LEDs because the resistors limiting current to them (R_TRL_LED and R_RESP_LED) are so low - the pins are only rated for around 4ma, so unless those LEDs have a large voltage drop there will be significant current going through those resistors.

Actually, that's the one other thing I updated with the change to Teensy 4.1 - switched the LEDs from through-hole to SMD. The new TRL_LED has a forward voltage of 2.15 V, and RESP_LED has Vf of 3.2V. I calculated the resistors to power the LEDs at 10 mA (since that's what the 3.6 could support) but you're right, the 4.1 has a recommended max of 4 mA! Pulling too much current could be causing Teensy failures, so I'll increase the resistor sizes and see if that helps.
Thank you!