The only check I can suggest is "Is the standby light on?", as the
commonest problem is that the power is off at the wall or it has tripped
Either that or the remote control has a flat battery.
Sorry if that's not much help, but the local TV guys want an arm and a
leg to prize them out of the workshop nowadays. If they are passing this
way, I can have a quick look as they pass Longport, but my workshop days
are long gone.