My frg-120d screen was blank because there was a solder crack on the ribbon cable connector on the main pcb board. The cracking could be seen with a x10 lens and good lighting. The solder can be 'repaired' by remelting it with a hot soldering iron and preferably a little flux.
Normally solder cracking occurs on hot components, but here I think the ribbon cable was too short and was pulling on the connector.
D Empson, March 2022
