DevTerm Suddenly Unresponsive: Seeking Diagnostic Assistance

I’m seeking assistance with a Clockwork DevTerm, which is currently unresponsive. I received it from a friend, who said it was working until there was a sizzling sound from the bottom left corner (near the power button - though it might have been from the speakers on the other side), and maybe a burnt electronics smell. I figure a board fried and I’d like to diagnose which one it might be. Here’s a summary of the troubleshooting steps I’ve undertaken:

Power-On Behavior:
When I press the power button, the green power LED illuminates, and the screen flickers briefly, but no further activity occurs.

Power Sources:
I’ve attempted to power the DevTerm using both fully charged 18650 batteries and a USB-C power source, but the issue persists.

Operating System (OS) Image:
I have re-flashed the SD card with the appropriate OS image for my DevTerm model, versions A06_v0.2f and v0.1a using Balena.

Display Connection:
I have inspected and reseated the display ribbon cable to ensure it’s properly connected, with no visible damage or loose connections.

Serial Console Access:
I connected the DevTerm’s EXT board to my Windows 11 laptop using a data-capable micro-USB cable.
The laptop recognizes the connection as COM4, but attempts to access the serial console using PuTTY (configured with baud rates of both 115200 and 1500000) resulted in no response.

Compute Module (CM4) Orientation:
I have verified that the Raspberry Pi Compute Module 4 (CM4) is correctly installed on the adapter board, ensuring proper alignment and connection.

Internal Connections:
I have disassembled and reassembled the DevTerm, checking all internal connections, including ribbon cables and module interfaces, to confirm they are secure and properly connected.

Despite these efforts, the DevTerm remains unresponsive beyond the initial power LED illumination and screen flicker. I am seeking advice on further diagnostic steps or insights into which component (EXT board, main board, or CM4) might be at fault and should be considered for replacement. Any guidance or similar experiences shared would be greatly appreciated.

Buy a CM4 carrier board and see if the module still functions. If it is dead, do not put another cm4 in the devterm until you are certain the rest of the machine is OK.

Thank you for the suggestion. If it’s not the carrier board (or CM4), how can I go about testing the rest of the system?

I might buy a cheap Pi cm3+ for testing, better to burn up $25 than $100.

Quick question: In the original post you write

And a little down you write about the orientation of the compute module 4. Did you actually flash the A06 image onto the SD card? If so, try reflashing the proper image for the CM4 and see if the issue persists, as the A06 is an entirely different core and won’t work with a CM4.

@Seteris Thank you for chiming in. I received this unit in a broken state so I didn’t notice I was using the wrong image. The DevTerm was working for the original owner for a bit so I will assume they were using an appropriate image.

I reflashed the following three images on two different microSD cards (16GB and 128GB) without success: DevTerm_CM4_v0.2b_64bit.img, DevTerm_CM4_v0.1.img, DevTerm_CM4_v0.3e_xfce_64bit.img

At this point I’d like to try tracing voltages and signals from the power supply through the CM to the display to try and identify where the failure is. I’m using the schematics from here: DevTerm/Schematics at main · clockworkpi/DevTerm · GitHub I didn’t see a signals map but perhaps just tracing the clock signals will suffice.

I’ve noticed from the Clockwork store that the only parts available are the CM4 adapter, main and dev boards. I might be out of luck if it’s the power, ext or display.

Again, thanks for contributing - I’m still learning, here.