I have a test circuit connecting an ESP-8266 WiFi module to a MAX7219 LED driver. The setup is powered by a modified ATX power supply for both 5V (the MAX7219) and for 3.3V (the ESP-8266).
The setup worked fine for days with the first ESP-8266 unit I purchased. Photos of the setup are below.
I later purchased two additional ESP-8266, flashed them with the identical code, and substituted each of them into the circuit for testing. They each work fine for about 15 - 30 seconds, and then the whole ATX power supply shuts off.
The only time this power supply shuts down like this is when I have short circuited something. But I am not sure how different ESP-8266 modules could have a time-delay short?
I am really puzzled because I would think a short would happen right away, not after a few seconds. This behaviour happens with both of the new ESP-8266 modules I purchased, which makes me think manufacturing defect is unlikely.
While I did buy all ESP-8266 modules from the same e-bay vendor, I noticed that the last two (non-working; B & C in photo) are not identical to the first (working; A in photo). The circuit traces seem to be slightly different.
But all the spec sheets I found indicate that all of these ESP-8266 should be wired the same way. The only device differences I read about are with different amounts of on-board memory, but I am not sure how / why that could possibly lead to a hardware short circuit.
I am not really sure what is going on and would love any insight.
As requested, I monitored current / voltage for each of the various ESP8266 devices. I do not have an oscilloscope to look for spikes - I used two multimeters and watched manually. Here is what I observed:
GOOD 3.35Vdc 20mA-60mA
BAD (#1) - repeated 3 times, same behaviour 3.32Vdc 70mA cut out ~20s
BAD (#2) - repeated 3 times, similar behaviour 3.32Vdc 74mA cut out ~60s, 30s, 10s
GOOD (repeated) 3.35Vdc 20mA-60mA (fluctuating; seems a lot "noisier" than the BAD chips)