Just an additional note which may help, before you take a soldering iron to the RFM69 module…
I’m not completely clear on how your original system was configured,
but …
if it was an emonTx3 (Arduino) for measurement, connected wirelessly (radio) to a raspberry Pi3 for emonCMS/emonHub data collection (i.e an emonBase)
and
Then as your system has has been running for some years, there have been changes that you might not be aware of:
1) There are now two main radio protocols used. They are not compatible. I am guessing that the changeover between the two was about February 2023
a) The older one is called Jeelib Classic format.
b) The newer one is called the LPL (Low Power Labs) radio format, and is the default now.
2) There are now two radio modules for the emonBase.
a)The older RFM69PI module has a RFM69 radio module and an atmega 328 controller. It talks to the Pi via the Pi AMA0 serial port. The atmega 328 controller can be programmed to receive either LPL or Jeelib protocol. The atmega 328 firmware can be changed from the Admin > Update page.
b) The newer RFM69SPI module just uses the RFM69 radio module, and talks to the Pi via the Pi SPI port. The decoding of the radio format is done in the Pi. The SPI decoder in emonHub is only for the LPL protocol. The RFM69SPI module is the default sold by the shop now.
So basically if the firmware on the Pi3 and emonTx3 have been updated to different versions of the radio protocol (JeeLib vs LPL), they will not be able to talk to each other.
When updating, the radio protocol is a choice box at :
Admin/Update/Update Firmware Only/Radio Format
There is some background information on radio formats etc at
I don’t know if this helps or is an irrelevant complication!