My Black Rose wouldn't switch on yesterday, and it turns out the fuse in the games line cord had blown its a T5 Amp ( 240v game in the UK) . After a bit of head scratching discovered that the line filter module has an internal short. The Varistor and thermistor are still fine. I've jumpered out the line filter and the game works again.

My question is- does a pinball really need a line filter? The line cord goes to the transformer which surely will protect the electronics from any high frequency noise on the power line and also protect out-side world from any noise generated in the pinball? I was tempted not to bother replacing the filter box. What do we think? Here's a picture of the type of thing-

filter (resized).jpg

I agree I can't see any need to replace it. I suppose there may be a spike from the transformer when switching off as the magnetic field collapses in the primary, but the switch will have broken the connection to the mains source as this happens. Perhaps low frequency noise or single spikes might be a problem. As for any high frequency noise or RF, I don't think anything remotely high frequency will get through a pinball transformer of that size, as it's designed to work efficiently at 50/60Hz. Also on the secondary side the bridge rectifiers will isolate the rest of the machine from the transformer. Unless anyone has thought of something else I should think about? It's not really a problem, Its not a difficult or particularly expensive thing to fix, it just got me thinking 'why would I do this'!