I use ESP01 and I encounter a problem with a specific hardware module and no probem with other modules, let's name ESP01-bad the one with problem and ESP01-good any of other modules.
1/ ESP01-bad and ESP-01-good are flashed with the SAME program AI-thinker
2/ I use AT commands
3/ on ESP01-bad AT commands are OK except AT+CWLAP
4/ on ESP01-good when I use AT+CWLAP (after AT+CWMODE=1 to set Station mode) I got the list of all surrounding wifi networks around my place
5/ on ESP01-bad when I use AT+CWLAP (after AT+CWMODE=1 ) I got just one or two or no wifi network
6/ when I use other sketches not related to Wifi (ie activate GPIOs) ESP01-good and ESP01-bad work identically
7/ I carefully check the antenna circuit on ESP01-bad, redo some soldering, I even changed the capacitor between the chips and the antenna but nothing change
do you have any idea regarding this problem ? Thanks