You need to be systematic in your testing.
Important: when the blade broke:
(1) was the motor running? If so,
Check #1: THE FUSE IN THE PLUG. Test it with a meter or substitute a new fuse (13A). They do get 'tired'
and the voltage surge* from the motor suddenly coming off-load might have blown it.
(2) did the motor stop on its own, or did you turn the machine off manually?
Check #2: If the motor stopped on its own (or it wasn't running at the time the blade broke), check the safety microswitches inside the wheel covers (the doors). There is most likely to be physical damage to at least one of them, probably from the flailing blade as it broke.
Any mechanical damage to the switch should be obvious, but if not: PULL THE PLUG OUT, and put a test meter on the Ohms range, across each microswitch in turn. Activate the microswitch, or try to (mine has a hole in the door surround - you can poke a nail or screw in to work the switch). You should see the resistance change from very high to very low, and back when you release the pressure on the switch. There will also probably be a quite obvious click.
Only then try the NVR switch, as it's the least likely source of failure in these circumstances.
Hope that helps.
Microswitches should be cheap and easily found on the web somewhere. They're almost always over-specced for small bandsaws, so pretty much anything in the same style will probably do, and ones intended for other purposes can be adapted to fit. An exact replacement from the importer will probably be needlessly expensive.
If it really is the NVR switch, I'm not impressed. Blade breaking is just something that happens often enough and the switch should cope. If it did fail, I'd be keen to find a better one, not an identical one.
In my opinion, an NVR switch for a bandsaw IS a good idea, so don't wire it out and fit an ordinary wall switch. Axminster sell a couple of nice boxed ones (see:
http://www.axminster.co.uk/axminster-nvr-switch , for example), that you could fit tidily to the machine fairly easily. I very much doubt it's the problem though.
If in any doubt about how to correctly use a test meter, etc., you really ought to find better qualified help to do it. Also, if any sawdust really can get into the NVR switch, it shouldn't - there should be adequate sealing (a box round it with cable grommets, etc.). They are essentially electro-mechanical devices. If it's really cheap and nasty, replacing it will be a good idea.
E.
*actually the current associated. The voltage spike might just have killed the NVR switch's solenoid, but as I said, it should be designed to cope.
. Thanks!
