Seeking schematic for Servomet spark erosion machine

I'm helping out a local model engineer who has a Servomet EDM that's been sitting for 20+ years. I've done some initial fault finding and managed to get it powered up, but it's now started blowing fuses. I'm now desperately in need of a schematic to help me fault find the machine; can anyone help?

Hi

Not sure if this could be of any help. I have a eurospark H300 which I have the schmatic drwaing for.. Loklyhood is its not going to be aplicaply but if it could give you an idea then I'll send you a coply.

Is the fan working?

Hi Rob

This is a 60's machine based on valves, not sure if the 300 is as old as that. The fan was working, as was the whole machine, before it started blowing fuses.

Thanks, Martin

Old electronics - usual suspects are capacitors - they absorb damp, dry out etc, especially electrolytics. Carbon resistors tend to rise in value over the years and the rise can be large. These things can be checked out whilst you are on the hunt for a schematic. (unless the component markings have vanished!). You can get an ESR meter to check the caps off eBay for less than £20. Chinese of course.

I don't know where the machine has been stored, but keeping the electronics at around 25C for a few days to dry out is one tip I've been given (fan heater blowing through the cab) and the other is to bring the supply voltage up slowly with a variac over 24 hours is another, to give the caps chance to remember what their job is.

So I didn't answer your question at all - but maybe there is something useful here.

Steve

If there are valves, there will probably be a transformer in the box. It could be that, or one of the valves could have developed a short. What are on the valves re. numbers or letters?

> don't know where the machine has been stored, but keeping the electronics at around 25C for a few days to dry out is one tip I've been given (fan heater blowing through the cab)

In about 1984 I had an old valve telly. I left a packet of butter on top, and when I picked it up the butter had melted and poured through the back of the set.

After that it would only work when thoroughly warmed up. I used to put and electric convector heater under the back for half an hour before switching on. I didn't watch a lot of telly then (or ever, really).

Neil

Next thing to look forb after(maybe before) is dry joints in the solder of all the wiring. Unplug, and discharge all the capacitors, go over all the joints. Now clean the pins and sockets of the valves. Chase the spiders out. Ian S C