Automated Fixtures Martin Roboscan Pro 218 MKII with problems

J

jonjchris

Member
Hi All,

I am new to this forum and and looking for some answers about an old Roboscan 218. I recently acquired this light on an auction for $10 in a partially non working condition. When I power the light on, the bulb strikes, and the fixture runs through its startup. The issues i am having is that the pan and tilt motors don't move and I can not make it respond to dmx.

I have opened it up to start diagnosing the problem. I have found that on the motherboard, the 2amp fuse is blown. I have tried replacing this fuse but it will blow again as soon as power is applied.

Any ideas about what could cause this?

I would like to get this fixed but don't want to spend tons of money on an old light. If I can get it working, well great. if not, I am not out much money.

Any help would be greatly appreciated.

Thanks,
Jon
 
Did you try flipping pins 2 and 3 on the DMX input? A lot of their older gear that was dual protocol (Martin and DMX) had pins 2 and 3 flipped with respect to DMX signalling conventions. I know the 518 line needs a polarity reverser to work. I double checked the 218 Mark II manual, and it needs pins 2 and 3 on the DMX line flipped for it to work.

Also, are you sure its a 218 Mark II? The 218 Mark I was Martin only and needed an external DMX->Martin translator box. Double check your DIP switches against the manual and make sure everything is set where you think it is. Also, make sure the pan/tilt lock screws have been removed. I still keep 4 of the 218 Mark I in service, along with some 518s and 918s. Its interesting using them with modern consoles like a Road Hog.
 
BobHealey said:
Did you try flipping pins 2 and 3 on the DMX input? A lot of their older gear that was dual protocol (Martin and DMX) had pins 2 and 3 flipped with respect to DMX signalling conventions. I know the 518 line needs a polarity reverser to work. I double checked the 218 Mark II manual, and it needs pins 2 and 3 on the DMX line flipped for it to work.

Also, are you sure its a 218 Mark II? The 218 Mark I was Martin only and needed an external DMX->Martin translator box. Double check your DIP switches against the manual and make sure everything is set where you think it is. Also, make sure the pan/tilt lock screws have been removed. I still keep 4 of the 218 Mark I in service, along with some 518s and 918s. Its interesting using them with modern consoles like a Road Hog.
Click to expand...


My fixture is for sure a Mark II, at least acording to the Martin label on the top of the fixture. The xlr jacks on the top of the light do say Serial Data Link... this concerned me a bit, but after reading through the manual I thought it was dmx. I will try the pin 2/3 swap and see what happens.
 
Most likely an issue with pin 2/3. Roboscan products all are like that, except for the 805, 1012?, Robocolors, which require a converter box (similar to a High End Systems brain) that converts dmx to martin protocol. Most of us who had Roboscan products just made a pin swap cable for them and put a piece of colored tape on it.
 
As others have said, pin 2/3 swap. It's for all of the old Roboscans and other fixtures from that era. Also, if that doesn't work, replace the addressing dipswitch. I've got some Roboscan 518 Pros and replacing the dipswitch fixed a random DMX drop issue that I had where sometimes it just wouldn't listen to DMX.
 
I built a pin 2/3 switch cord and this fixes the dmx problem. I am still blowing the 2amp fuse on the mother board and have no pan and tilt. The motors are not getting any power. Does anyone have a wiring schematic for this light? Other than the pan and tilt all functions of the light now work. I think there is a little hope for this old light.
 
Did you check to make sure the pan/tilt motor lock thumb screws have been removed? IIRC, the pan/tilt motors each connect to the main board via molex style connectors, so once you verify the motors aren't locked in place, should be easy to disconnect and test one at a time (I'd unplug before changing any connections).
 
The motors are not locked. This was one of the first things I checked. I think more than anything my issues is with why the 2amp fuse on the board is blowing. The fuse blows with or without the pan and tilt motors plugged in, and I am assuming that power is supplied to these motors through that fuse. This is where a schematic would be nice to figure out what is before and after the fuse in the circuitry line. At this point I am guessing that it is a bad capacitor or IC that is causing a power surge of some kind. Any thoughts?
 
jonjchris said:
I have found that on the motherboard, the 2amp fuse is blown. I have tried replacing this fuse but it will blow again as soon as power is applied.
Click to expand...


Good Morning, Jon.

It's likely the bridge rectifier in the DC circuit is bad.
This is board level work & should not be atempted if you haven't worked on PCB's before.
On the other hand, for $10 ...... what could you lose?
 
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