Cleaning a Power Bank

One common option to supply the small TTGO LoRa boards is to use a small power bank. For supply small devices like these boards I use one really cheap power bank, so cheap it can be obtained for 0.80 euros from China (with no 18650 li-ion cell included, of course).

The 0.80 euros power bank

It seemed to work just fine but powering a 433 MHz TTGO board I noticed the power bank itself radiates a lot of noise in this frequencies.  UHF noise from a switching mode power supply is a new record for me!

But... Can it be cleaned?

Fuses in TTGO LoRa V1.6

Today, probably the most common ESP32 LoRa board is the TTGO V2-1.6. In a very small factor it offers OLED screen, WiFi, Bluetooth, micro SD slot, li-ion charger... and a lot of problems.

The problems seem to come from the polyfuses installed in the board. There are two of them, and each one offers a different set of problems.

The Screaming TTGO T-Beam

If you are playing with LoRa devices it is pretty sure you have some ESP32 LoRa boards, and probably a ESP32 based TTGO T-Beam. This board is quite interesting because it includes a GPS, making very easy to compute distances of messages sent and received through LoRa chips.

TTGO T-Beam ESP32 based LoRa Board