MAC 500 - Tilt Issue - Another one!

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   Hi,
I'm in the process of refurbishing a MAC 500 to use and have a minor but irritating issue with the unit. The problem is that the tilt movement is not running as smooth as I would have expected. The tilt operation does not flag up any errors and it always locates and positions correctly. The pan in contrast is working ok and runs quite smooth.

I have tried all of the usual things including swapping over the pan / tilt drivers, checking continuity of the wiring in the loom. I have removed both of the tilt stepper motors from the yoke and both feel normal in terms of shaft rotation and have metered out the stepper motor windings on both motors and again all ok. When the unit is powered off the head moves very freely without any trace of sticking so I feel this rules out any mechanical problem such as a dry or knackered bearing. 

I have re-calibrated the two motors as per the manual and again no improvement. I have also tried switching off the feedback option in the menu and again without any change.

In every other aspect the fixture is working fine with no errors being reported. The unit has clocked up quite a number of hours but is in good condition and in fact is quite usable as it stands. However it would just be nice to sort out this final issue.

Any further ideas anyone?

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whizzzy Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 08 October 2008 Location: Warwickshire Status: Offline Points: 70	Post Options Post Reply Quote whizzzy Report Post Thanks(0) Quote Reply Topic: MAC 500 - Tilt Issue - Another one! Posted: 22 July 2013 at 1:55pm
	Hi, I'm in the process of refurbishing a MAC 500 to use and have a minor but irritating issue with the unit. The problem is that the tilt movement is not running as smooth as I would have expected. The tilt operation does not flag up any errors and it always locates and positions correctly. The pan in contrast is working ok and runs quite smooth. I have tried all of the usual things including swapping over the pan / tilt drivers, checking continuity of the wiring in the loom. I have removed both of the tilt stepper motors from the yoke and both feel normal in terms of shaft rotation and have metered out the stepper motor windings on both motors and again all ok. When the unit is powered off the head moves very freely without any trace of sticking so I feel this rules out any mechanical problem such as a dry or knackered bearing. I have re-calibrated the two motors as per the manual and again no improvement. I have also tried switching off the feedback option in the menu and again without any change. In every other aspect the fixture is working fine with no errors being reported. The unit has clocked up quite a number of hours but is in good condition and in fact is quite usable as it stands. However it would just be nice to sort out this final issue. Any further ideas anyone?

aziz Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 12 January 2011 Location: ireland Status: Offline Points: 139	Post Options Post Reply Quote aziz Report Post Thanks(0) Quote Reply Posted: 22 July 2013 at 2:08pm
	It could be a problem on the main board,even though the driver is ok,there are smd resistors next to it that go and will affect movement.

whizzzy Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 08 October 2008 Location: Warwickshire Status: Offline Points: 70	Post Options Post Reply Quote whizzzy Report Post Thanks(0) Quote Reply Posted: 22 July 2013 at 2:19pm
	OK, thanks for this. I'll pull the main board out and check the smd resistors around the driver. Have you any idea what sort of resistance value these should be? Thanks.

James Tengo Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 09 May 2008 Location: Nomadic Status: Offline Points: 2189	Post Options Post Reply Quote James Tengo Report Post Thanks(0) Quote Reply Posted: 22 July 2013 at 2:51pm
	Sounds like you might only be getting 8 bit rather than 16 bit control. Has been a while since I poked around one of them, what controller are you using?

aziz Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 12 January 2011 Location: ireland Status: Offline Points: 139	Post Options Post Reply Quote aziz Report Post Thanks(0) Quote Reply Posted: 22 July 2013 at 2:53pm
	No sorry,i don,t know what the values for them are,another thing to check properly are the looms especialy where they go thru the yolk and the head. Try to isolate the tilt wires and give them a bit of a stretch,as sometimes the break is tiny and you will get continuity when there is no movement but when the head starts to move it starts to stretch the looms and then you lose some power to the motor

aziz Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 12 January 2011 Location: ireland Status: Offline Points: 139	Post Options Post Reply Quote aziz Report Post Thanks(0) Quote Reply Posted: 22 July 2013 at 2:56pm
	Just seen james post and that is a good possibilty if you are using a controller. Use the test sequence in the menu to test all functions.

whizzzy Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 08 October 2008 Location: Warwickshire Status: Offline Points: 70	Post Options Post Reply Quote whizzzy Report Post Thanks(0) Quote Reply Posted: 22 July 2013 at 2:59pm
	Hi James, Thanks for the suggestion but both the MAC and the controllers have definitely been set up for 16 bit. I have tried two different controllers, one being a Fat Frog and the other is a laptop running ShowMagic via an Enttec, USB to DMX interface. As the pan is running smoothly and the pan fine and tilt fine are all functioning then this also indicates that it is running on 16 bit.