Denford Software & Machines

Hi there,have got an Orac of 1985 vintage,sn.31145/c/n/c, model TD8/o/r. Slight problem though, it refuses to move in x, whether in auto or manual. However the manual screen believes it is moving and will merrily count up and down. Lathe is new to me, but have operators manual, and some wiring diagrams but no additional software or maintenance/ diagnostic paperwork, however do have experience of similar systems thru work. Am hurco operator by trade and do wiring and maintenance at work so am not afraid to delve into the murky depths, just need some pointers on where to delve and what i should be looking for! Any help much appreiciated!
Steve

Hi Steve,

It sounds like you have a faulty x axis drive card. The best thing to do is drop the front control panel down. It is hinged with a couple of countersunk srews fastened through the front of the cabinet. Once inside you will see the rack next to the monitor. The X & Z drives are the two cards nearest the monitor. They will probably be CD20`s. If so they will have 4 LED`s. I think that one is green & lights every four steps & the other three are fault`s. It is possible to interchange the drives by releasing the retaining bar fitted in front of the rack & then sliding the drives out.
If it does turn out to be a faulty drive it may be worth posting a link on the Forum. It may be that someone has a CD20 that is surplus.

Good luck.

Hi Steve

Presume that this is a PNC 3 controlled machine? If so have you had a look at the control maintenance manuals I posted a while back ?
Try here
https://denfordata.com/bb/viewtopic.php?t=434
This gives the diagnostics procdeures.

Be warned though - according to the manual -
"The X, Y and Z stepper motor drives provide power to drive the X, Y and Z axis stepper motors. The X and Y
axis drives are SD2 types. The X and Y drives are not interchangeable, as the link settings are different. The Z
axis drive is an SD3, which is more powerful than the SD2, this drive, should not be fitted in the X or Y drive
position."

There is also a manual I placed in the download section for the Digiplan drives. Is the motor making any noise? Are you sure it hasn't stalled?

Cheers

Dave

D'oh - ignore my last post - for some reason I thought you had a Triac - must have been the need for coffee!!!

Anyhow - have you hit a limit switch, or you may have had a switch go faulty. I take it you have tried to hold in the override switch while moving?

Cheers

Dave

I still think that the most likely cause is a fault on the X axis drive. The control will be a "GSM Sintel" version MKIII. It is possible that it may be fitted with SD3 drive card but more likely CD20`s as stated previously. If it was a limit switch or a problebm with the supply voltage the Z axis would show the same error.

Start with the obvious checks:

Cables and connectors all in place and not corroded / damaged - follow the wires back from the motor as far as you can.

Fuses ? - I'm not sure if there are seperate fuses on the drives - if the Z is working OK but not the X ?

Like David said - does it make a noise but not move ? If so, then its going to be mechanical (adjustment strips have jammed or the bed/ballscrew has just rusted up)

Hi

Just remembered that there are two fuses just after the main power supply, one per axis - I'm not sure if these are accesible outside the case - I will try and have a look at the one in work.

Martin - is the CD20 the rack version of the SD drivers? There are certainly 2 or 3 fuses on the SD drives underneath the heatsink.

Does the X axis motor get warm at all if you leave it?

Cheers

Dave

Hi

Just had a look at the machine here and the wiring diagrams and there should be fuses - but they don't seem to be accesible from the outside. They should be next to the capacitors and rectifiers on the big transformer for the drives. From memory they are 20mm fuses and my mate had difficulty finding them, so he changed the holders for 1" holders. However since then I have found this company who do a good range of 20mm fuses. https://www.rshelectronics.co.uk/

Cheers

Dave

Hi there, thanks for all your replies, just dropped the front panel down armed with meter and manual to find......... only one axis drive card fitted! Certainley a CD20 though, four led's (1 green, 3 red) and large black heat sink to right, so, has anybody got a surplus one for sale???

There should be 2 CD 20's one for each axis.

Are you sure there is only one? Has someone taken the other out? That would explain why the axis does not work?

Hi

Noticed this lathe on ebay - might be worth it for the extra spares!!

Item 170054109764

Cheers

Dave