All Characters Filament Display On

To be honest I m not 100% sure if they are LEDs the thing is its quite an old system knocking on for 20 years old. As you say if it is the vacuum filament type they do wear out but....the tuner has always been dimmer than the other displays so if anything were to wear out it would be the brighter ones? Also I m sure I've read something about boosting the display with a higher voltage but I have no idea how to go about this. I have three options

1. Look out for another tuner on the second hand market.

2. Live with it.

3. Fix it.

Option 3 is my choice as I am retired now and have the time to mess about with it and although this may sound strange I have got attached to the thing. They dont make them any more indeed Aiwa although an excellent make went bust not through quality issues but because they didn't plan ahead into the digital era.

https://www.electronicspoint.com/forums/threads/faint-display-on-aiwa-tuner.276610/

Thanks