What would the pros and cons be of sticking them in all those spots?dknguyen said:You can stick it between the outputs of the bridge rectifier, the inputs of the transformer, or the outputs of the transformer, depending on the breakdown voltage rating of the varistor. You could also stick it between the outputs of the power supply. Best place to stick it is wherever the transient is most likely to enter first and damage something first (make sure the breakdown rating is appropriate for where you stick it).
I've never bothered either, but the UK has exceptionally good quality mains! - on lots of TV boards you find loads of empty holes for mains filtering used in some other countries.Hero999 said:I don't normally bother. The transformer is inductive so high frequency spikes are likely to be heavily attenuated and if the transformer doesn't stop them the regulator certainly will and is unlikely to be damages unless it's a really high voltage for a long period of time.