I have 2 spare scopes that haven't been used for years but when fired up my Farness 2ch DTV20 only the screen grid illumination works. On my Kikusui 2ch DSS5040 both green traces light up and Ch1 works correctly. Ch2 gives an adjustable trace but will not measure the calibtation test post voltage, or even a AAA battery. No amount of swapping bnc cables and switch flicking helps. Any ideas please

 

This actually calls for two separate threads.
Since CH1 on the Kikusui is working I suggest that you start on the Farnell DTV20.

Farnell DTV20 discussion here.