A model number would be helpful.
If it is the typical flourescent display(digits are inside a glass tube/panel), dimness is nearly always caused by failing capacitors in the filament bias supply(usually a -18v to -36v supply) or a zener diode or resistor in that supply.
If it is actually LED, then you'll have to hope that it's not a custom LED module(s), as fading LED's virtually always means the LED segments themselves are going south.
And I certainly hope there was never a Wadia model with backlit LCD. That would be too cheesy.
Dear learned colleagues,
I now have this Wadia 301 with faint display that needs fixing.
The LED part which shows pre-amp gain level and also and lights up control buttons (and works off Wadia board) was working fine.
The VFD part that is being driven by (presumably) Pioneer servo board and which shows track info etc., was very, very dim.
Barely showing bottom row of track number grid.
So I replaced VFD using one which I removed from Pioneer PD-S703 which was exactly the same and had the same part number.
Now it is a bit brighter and I can see all the segments but the info is mostly scrambled.
So I am after info on this Pioneer,s servo board.
Does anyone know which Pioneer it comes form?
I do not post the link to the video about this player because it is too sales oriented. But is someone is interested, it is on my hear-net-au uTube channel: https://www.youtube.com/c/hearnetau/videosThere is probably not much of value there for the real Pros here, but novices might find some useful info and see how some players look inside (and I need couple of hundred more subscribers, or so I am told). Sorry for the shameless plug.