Turned my router control box on yesterday to be greeted by sound of fuse popping. After a bit of poking around, it looks as if the toroidal transformer for the main power supply has failed. It's a dual-output 68V/5V unit, but with all transformer secondary windings disconnected, it still blows the fuse. It's been running very happily for around 3 years off a 5A mains fuse so when it starts taking out a 13A fuse, that seems pretty conclusive. I've no idea what the primary winding resistance of a transformer like this should be, although 2.5R seems a bit on the low side. Anyone have any idea of what a 500VA toroidal transformer primary should measure?

Unless anyone knows better, a new transformer from Airlink seems to be on the cards. They don't appear to have an exact equivalent of the nominal 68V transformer in the existing power supply, so I shall have to go for a 2x25V or 2x30V. I'm currently using m752 drivers (nominal 75V max) although the new machine will be using EM806 (80V). I would measure the actual secondary voltage and output voltage of my existing supply but that's not really possible any more. Any thoughts? I do know that more volts is better, allowing a bit of margin for magic smoke territory. I'm using a 24V supply at present just so I can get a job done, and I've had to slow the machine down enormously, even though it wasn't that fast in the first place. The only good bit is that I have an old PC power supply in the box which just runs a case fan and supplies switchable 5V/12V for the cooling pump, so I can use that for the 5V needed for the BOB.