[Techman]

It's not disconnected from the mains - it's just switched off at the on/off switch. It's probably got a pole down due to having been welded closed when the suppression caps went bang. Whoever replaced them should have checked for this as it's a very common thing to happen, and can leave a chassis live when the set is switched off.

Remember, those dial bulbs form part of the heater chain in conjunction with the resistor that they're across. It might be worth checking that this resistor, or the connections to it, aren't dodgy. Clip a meter across it and go round with an insulated screw driver handle and tap tap tap it while carefully watching the meter. Also tap other components, particularly the rectifier, but be ready to switch off quickly if there's a blue flash!