ORAC Z axis not driving.

[PDobson]

I have read the thread on the Z and X axis not working, but in my case it is the Z axis only. (X and spindle are fully operational) On the manual move page the Z position indexes as you manually select to move the Z axis but no actual movement. I have not yet split the lathe from the electronics deck, is there anything I can check in this state before seperating the lathe and electronics??

Model No: TDS/O/R/C/N/C
Ser No: AC23074N/2
Z drive card: CD20 Ser No 2027/02
X drive card: CD20 Ser No R8-2520/47

I could not work out from the previous threads whether the Z and X drive cards were interchangeable to see if the fault is on the drive card (thought I'd ask before trying it).

Also the display is not line locked (Frame lock is fine, also reported elsewhere). If it is a loose video connections, can I get to it without splitting the lathe/electronics deck?? Is there a line time base adjustment on these displays?? To get over this I am using an external monitor tuned to Ch 61 and that works fine.

Cheers Pete Dobson, Farnham, UK.

[PDobson]

I have just checked the state of the drive cards. Each has 4 LEDs. The X drive that works the top Green LED is on and responds to commands to move. The Z drive card has the third LED down from the top (Red) permenantly on. No other LEDs respond to any move commands. What does the third LED down signify??

Cheers Peter D.

[Martin]

You can see a fault description on page 45 of the manual.

https://www.parkermotion.com/manuals/cd/CD20-30.pdf

[PDobson]

Thanks Martin, that is great, As a result I have found two of the four power transistors have gone short circuit. To check out the operation of the entire card it would be great if I can find the circuit schematic for the CD20 card. Is this information available?? Standard googles searches drew a blank.

Cheers Peter D.

[Martin]

Hi Peter,

I don`t think Parker ever released any electrical drawings for the CD20 drives.

[PDobson]

OK Thanks, I'll persevere with changing the two output transistors and see what happens.

[PDobson]

Following on from the earlier post, I now want to separate the electronics tray from the main lathe base. I thought I read somewhere else that this is achieved by putting the ORAC-1 on its back, undoing the tray fixing screws around the edge of the unit and dropping the electronics tray down on it's back hinge. This does not seem to work. All screws are out but there is something very positively holding the bottom tray to the base of the up turned lathe.

Could some one explain to me how to separate the electronics bay from the lathe???

Then I can start fault finding the Z drive (or replace the electronics).

Cheers Peter D.

[PDobson]

OK, so I found a self tap screw that look as though it had nothing to do with the base detachment, now removed and guess what, the base swings down nicely revealing all that 1960s electronics.

I swapped the drive card for the Z axis with the X axis and now the X axis has stopped working so must be something to do with the supplies to the stepper motor drive cards. So I now have two cards to get going, but I can now start probing.

Cheers Peter D.

[triac]

Hi Peter

The original X axis card is working OK but when transposed with the Z axis the X axis stops working, doesn't this indicate the original Z axis is faulty or possibly the different card spec number is not suitable for the X axis.

Emgee

[PDobson]

Thanks for getting back to me.

I fear that the transposition has caused the X-Axis card to become damaged. when I put the X-Axis card back in the X-Axis slot, I no longer get any X drive and at least one of the red LEDs is now on (was not before).

When I get time I reverse engineer the card and try and get to grips with some sort of circuit diagram. It is a great shame I am unable to get my hands on the schematic diagram for the CD20.

My current thoughts are that each drive slot has its own power supply, and one of these has gone faulty damaging the card plugged into that slot.

The next test for me is to measure the voltages on all the back plane pins and make sure each card slot has the same voltages. Any difference will (I hope) indicate an issues with that slot's power supply.

Cheers Peter D.