The Craftmans Shop > New from Old
Rebirth of a Denford MIRAC CNC Lathe
awemawson:
So I took my courage in both hands and 'wired out' the Emergency Stop circuit, feeding 24v directly to the ES Relay and lo and behold everything sprang into life :clap:
We now have power to the axis drives and spindle motors and can home and jog etc :ddb:
Had to do a dummy trial using one of the programs resident on the original PC hard drive but first I had to work out how work and tool offset are stored - turns out they are in a common file on the HDD:
Having proved it now works it was a case of slogging through the Stop chain to find the fault, which turned out to be a voltage sensing relay that looks at a thermistor buried in the tool post turret motor. Although it's input was OK it's contacts were permanently open circuit. I've linked it out of the chain for the moment.
philf:
Andrew,
Looking good :thumbup: although the tool changer sounds as though it needs some grease. (Unless they always sound like that.)
I hope you're going to backup the hard drive before you do anything else!
Phil.
mattinker:
I'm glad to see it works, bit too easy though!!
Regards, Matthew
awemawson:
Thanks chaps - yes the gears or motor on the turret sound horrid - probably never been greased !
So the voltage sensitive relay - what to do ?
I could leave it wired out, and ignore the turret thermistor . . . .but that graunching sound . . . :thumbup:
I could buy another one, except that RS part 346-154 is now obsolete, and new equivalents are not only very expensive but also not an 11 pin base so physically different.
So nothing to loose I pulled the old one apart and having put my electronics head on started poking about for a look see. 110v AC comes in to a transformer followed by a four diode bridge with a filter capacitor across the input and a 100 mFd 40v electrolytic as a reservoir - pretty standard. Start testing the diodes and they all read 700 ohms BOTH WAYS - something wrong here, they should be that one polarity only ! Quck test of the capacitor in circuit - dead short :thumbup:
Whip the capacitor out, test the diodes, all is well this time. Pop a replacement 100 mFd capacitor in (35v working but it'll be fine) and do a quick test in circuit before replacing the cover. Well how about that - it works :ddb:
Pop the cover on, take out the link I'd put across it's contacts and it all seems to work - the tweaker gives a reasonable range and at one extreme the Emergency Stop Relay drops out just as it should. Well that saved a bob or two !
DICKEYBIRD:
Feels great getting making an old soldier healthy again doesn't it? :clap:
I have a Denford MicroMill and those chaps up in sunny Brighouse make a very solid machine . Mine's a training machine & has a puny little Sherline mill but the control is robust. I was going to use the original software as well but the lack of the magic dongle made that effort futile. I snatched off Denfords proprietary serial board & hacked straight into the SmartStep board with step/dir signals from Mach & a parallel port.
In searches on their site I found that they offer the old DOS software for free download, or used to anyway. There's nothing wrong with DOS & it probably works reliably without the influence of Windoze. As long as it will recognize the encoder, threading should be fine. I wonder if it came with any conversational programs or any CAM functions?
Gotta luv your :beer: projects!
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