Martin Mac 250 DIMMER ERROR

[nicknick2010]

Hi,

 

I am new here and recently bought some 250+ but one has a problem with the dimmer...

 

I have switched the shutter module over with three others that 100% work and it still has a fault. The shutter just won't close and seems to spaz out a bit before it returns to the home position.

 

Can anyone give me any advice on what it could be? as it clearly isn't the shutter it's the dimmer chip or something...

 

Thanks,

 

Nick

[colin_j]

Are you sure its not a mode issue? Could well be in the wrong mode would explain the irratic behaviour.

[law99]

Sounds like a driver chip to me. One on the PCB.

 

Do all three different modules show the same fault?

 

Get a driver chip from another unit and try it in the faulty light to narrow down the problem

[Jerome]

I remember I had a MAC 600 recently read DIER which is a dimmer timeout message. Did you get this reading? if so it the magnetic indexing circuit which needs someone to have a good look at it.

[marktownend]

OK, it's late and I'm tired so I apologise now if I either don't make sense or tell you complete rubbish...!

 

The chances are that it's either the stepper motor driver chip or the wireset leading from the PCB to the stepper motor. Check the wireset forst if you can as if there's a problem with that and it's shorting to earth then you'll only blow a new chip if you put one in. Checking the wiresets can be a pain - the main idea is to use a meter with a continuity beep, moving the head for the full range of it's pan and it's tilt (with the unit disconnected from the mains!) to check if any of the wires are broken or only complete in certain positions. Also worth doing a similar check on each wire for the full range of movement but this time measuring them to earth in case there are any that have worn through the insulation and are touching the casing. If you find a problem with any wires, you'll obviously have to change or 'bodge fix' them. And I think the 250 is the same as most moving heads in that there are 2 wiresets - 1 between the base and the arm and the 2nd between the arm and the head. You need to check both of them I'm afraid!

 

Hopefully you'll find the fault this way, but if not then it may be worth changing the driver chip, but if it is blown it's probably because 1 of the wires has shorted to earth so don't expect it to last...

 

Hope this helps, I'll try to remember to re-read it in a couple of days once I'm more awake!

 

*** Edit to add request to OP as to why he put Nick at the end of his post but his profile says his name is Bob Mar-ley? We prefer round here for genuine details to be used in user profiles... ***

[DrV]

Driver chip or wiring loom.

 

There's only one wireset from the controller up to the head as the controller is in the arm, but there is a little PCB somewhere up top which splits the wires off to the two steppers. I assume from your description that both halves of the shutter are behaving the same. First port of call should be this PCB as it gets hot and they are notorious for failed solder joints.

 

To check the wireset for continuity take the plug off (PL511) then link the two middle wires with a bit of thin wire pushed into the sockets. Then connect your meter across the other two wires - you'll see the equivalent resistance of one winding (two in series but there are two motors in parallel) This should be around 140ohms. Wiggle the loom and the head around and check that it doesn't change to ensure there are no breaks.

 

To check isolation from earth just move one of your meter probes to the chassis, leaving the other on the stepper wire and this time you should see infinite resistance (move head and wireset as before). If you don't see any change in resistance on either of these tests THEN change the chip. Dimmer is the fourth driver up from the bottom.

 

Happy hunting!

Dave

[nicknick2010]

Driver chip or wiring loom.

 

There's only one wireset from the controller up to the head as the controller is in the arm, but there is a little PCB somewhere up top which splits the wires off to the two steppers. I assume from your description that both halves of the shutter are behaving the same. First port of call should be this PCB as it gets hot and they are notorious for failed solder joints.

 

To check the wireset for continuity take the plug off (PL511) then link the two middle wires with a bit of thin wire pushed into the sockets. Then connect your meter across the other two wires - you'll see the equivalent resistance of one winding (two in series but there are two motors in parallel) This should be around 140ohms. Wiggle the loom and the head around and check that it doesn't change to ensure there are no breaks.

 

To check isolation from earth just move one of your meter probes to the chassis, leaving the other on the stepper wire and this time you should see infinite resistance (move head and wireset as before). If you don't see any change in resistance on either of these tests THEN change the chip. Dimmer is the fourth driver up from the bottom.

 

Happy hunting!

Dave

 

Hi guys,

 

thanks for your help once again..

 

It was the chip :-) it's now fixed but now I have a problem with my other mac 250 the whole unit works perfectly apart from the pan... as I can see and hear from the stepper motor it seems to be slipping or to much/ not enough resistence on the motor. You lhave to nudge it a little for it to start moving and then it will start moving but still can't work out it's two stop points :S this one has really got me, is this the motor or something to do with to much weight on the centre cog? has anyone had anything similar?

[DrV]

Hi guys,

 

thanks for your help once again..

 

It was the chip :-) it's now fixed but now I have a problem with my other mac 250 the whole unit works perfectly apart from the pan... as I can see and hear from the stepper motor it seems to be slipping or to much/ not enough resistence on the motor. You lhave to nudge it a little for it to start moving and then it will start moving but still can't work out it's two stop points :S this one has really got me, is this the motor or something to do with to much weight on the centre cog? has anyone had anything similar?

 

If the unit moves freely when it's powered off then you are back to the same sort of tests as for the shutter. It may well be that one phase of the stepper/driver is not working. With the unit powered on and stationary you should need roughly the same amount of effort to overcome the pan stepper as the tilt stepper. If the pan is way easier then it's not doing its job.

 

Dave

[stuart.thompson]

Driver chip or wiring loom.

 

There's only one wireset from the controller up to the head as the controller is in the arm, but there is a little PCB somewhere up top which splits the wires off to the two steppers. I assume from your description that both halves of the shutter are behaving the same. First port of call should be this PCB as it gets hot and they are notorious for failed solder joints.

 

To check the wireset for continuity take the plug off (PL511) then link the two middle wires with a bit of thin wire pushed into the sockets. Then connect your meter across the other two wires - you'll see the equivalent resistance of one winding (two in series but there are two motors in parallel) This should be around 140ohms. Wiggle the loom and the head around and check that it doesn't change to ensure there are no breaks.

 

To check isolation from earth just move one of your meter probes to the chassis, leaving the other on the stepper wire and this time you should see infinite resistance (move head and wireset as before). If you don't see any change in resistance on either of these tests THEN change the chip. Dimmer is the fourth driver up from the bottom.

 

Happy hunting!

Dave

 

Hi guys,

 

thanks for your help once again..

 

It was the chip :-) it's now fixed but now I have a problem with my other mac 250 the whole unit works perfectly apart from the pan... as I can see and hear from the stepper motor it seems to be slipping or to much/ not enough resistence on the motor. You lhave to nudge it a little for it to start moving and then it will start moving but still can't work out it's two stop points :S this one has really got me, is this the motor or something to do with to much weight on the centre cog? has anyone had anything similar?

 

Sounds to me like its either a broken wiring loom or a problem with the driver chip.

 

1st thing to do is plug the PAN wireset to the tilt output on the PCB as they share the same type of driver chip. Power the unit up and see if the PAN motor comes back to life working correctly... If it does then the driver output on the PAN part of the PCB is damaged and needs the driver chip replacing or the resistors around the driver chip are blown and gone open circuit, if the PAN motor is still acting strangly then the wireset is most likely at fault and needs replacing.