Broken Stepper Motor

[djlee]

I've started doing a small disco round the local to drum up trade since they banned smoking the buggers :) Already had most of the gear as the old mans a singer on the local circuit but I had to borrow some lights from an old Dj friend. Got it home and it works except the Gobo doesnt move, basically I can set a color/shape and it will stay on that forever. Opened up the case and done a little investigating and I noticed that when I switch it on the motor atleast tries to do something as you can feel the vibration ect from motor on the motor housing and the gobo wheel (nits not vibration from the fan I checked that).

 

So I moved the mirror round which works with my finger and its quite smooth and easy, moving the gobo wheel however takes a little more force (not impossible to move but you can feel its a bit tougher than the mirror) and it seems a lot more jumpier (is that a word?).

 

So unless the gobo wheel and the motor itself is supposed to be that much different to the mirror one im guessing its buggered (both have same P/N's so I m guessing they should feel the same). Im wondering whether theres anyway to fix it, i.e. it might not be screwed but maybe it just needs oil or greasing or something to lubricate it so it can spin again (I dunno if your supposed to do that im not really that clued up on motors).

 

If theres nothing I can try to do to fix it and it is royally screwed where is the best place for replacement motor, preferably second hand just to get it up and running for a month or two til I can save up for a better system.

 

Oh forgot to mention its a Martin Destroyer running standalone (no DMX).

 

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On another quick note is there anyway to keep the bottom cool, its red hot within 10 mins and its slightly worrying. Would putting cling film in the bottom to reflect some of the heat back for the fan to expel it help, or just damage something else ?

 

 

Any help greatly appreciated ;)

[Matt Cowles]

The motor should just be replaced, you will not get any joy from trying to repair it. You can get Martin Spare parts from any approved Martin dealer....like us at Stage Electrics

 

You can always check ebay for Martin parts, if you are after a cheaper aternative, but be careful to make sure you are getting genuine parts.

 

As for putting cling film in the bottom.....please do not do this as you will melt the cling film in seconds. As long as the fan is working and kept free of dust and dirt the fixture will be cooling properly so there is nothing to worry about. The casing will get hot but there is very little you can do about it except keep it away from places where people can touch it and hurt themselves

[dwents]

As Matt said Repairing the Motor isn't really an option

 

The simplest test you can do is to unplug the broken stepper motor from the main Pcb

then unplug the working colour wheel motor and plug this into the suspect channel in your case the gobo wheel leaving the suspect motor unplugged.

then repower the unit if the wheel then works you will know that the electronics are fine and its either a stepper motor or cable problem.

if the wheel works you could also try swapping the cable from the suspect motor to the working motor if it has a plug at each end again this will eliminate the cable.

 

if the motor doesn't have a removable cable then you are looking at a new motor anyhow so either way its new motor time.

 

WARNING don't plug the suspect motor into another chanell on the main pcb as a faulty motor can cause components to fail on another channel.

 

you would then have two channels broken and a bigger repair bill.

 

when you say one motor is harder to turn is this with the power off as stepper motors are harder to move once power is applied.

if it is with the power off this will most likely be a Broken stepper motor.

 

also stepper motors are random beasts and come in many styles shapes and specification and the leads often dont come with a plug and may be wired incorrectly for your unit.

 

so I'd say always buy from a martin dealer as they will supply the exact part with a plug ready to fit.

 

Cling film did you mean tin foil ? if so also a no no

had Martin intended for tin foil they would have fitted it !

You could also have several other problems to consider regarding the heating bit

 

is fan working ?

is it right fan for unit or has it been changed for a lower spec one

is right bulb fitted ?

 

good luck with your mission

 

ps doing simple test like this can save you pounds but if you do incorrectly can damage your item beyond repair so if in doubt leave to a proffesional

[djlee]

thanks for the replies, I sort of already knew the answer to my stepper motor problem but as the guy in the matrix says, "ignorance is bliss".

 

fan's working

same fan that the unit came with as far as im aware

the bulb im not sure if the original owner replaced it, however he's usually pretty strict as to what parts he uses so im guessing he would have gotten the correct bulb

 

I did turn the gobo wheel continously for a while to see if it eased up but to no look, I did however find that when it resets at the start it is able to move the gobo wheel to the starting position (a little juddery) and it was able to move the gobo wheel a small amount when every once in a while but nothing that would pursuade anyone to think the motor is ok. I'll have to save up and look around for a new motor, chances are I can get a faulty unit from ebay thats got the same P/N motor as this one. But for now ive set the shape/color I want and disconnected the motor again, one shape and colour is better than none at all.

 

Thanks again for all your help and yes I did mean tin foil inside to reflect the heat from the bottom metal plate (dunno why I wrote cling film), but I guess as you say if it was something to be concerned about then martin would have done something about it