Old Golden scan 2. "not sure if I want one"

[Richard CSL]

I have a 1992 golden scan 2 down, it works fine on a showtec DMX master 1 cheapo chinese controller. distance .5M.

 

It works on my computer DMX dongle 80' away but stutters and looses positioning on the gobo chanel, and stutters on the shutter chanel. not sure about iris as someone has disengared the gears, colour seems ok but this is a snap to function. the drive chip electrolitic capacitors have slightly domed tops, indicating previous power problems.(I am in Tenerife so power problems are commonplace) I know this because I have already changed a load on a GS3. but this is not quite the same problem. that unit had the jitters on all chanels and the noise of the steppers was considerable until I changed the capacitors 2200uf 25v. on each channel.

 

I have noticed that the stepper driver board is run off 0-10V as this is another input on the rear of the unit. and the back circuit board must be the DMX control board. (And I would love to know, how do they do that with the fans , they run for 2 mins after the whole thing is powered off?? and no sign of a huge capacitor anywhere.)

 

Is this problem due to the baud rate / refresh rate of the DMX. I do have other GS2's in the venue on the same line, and they work perfectly.

 

Appreciate any help I can get.

[sleah]

The first question that is asked: Is the DMX line terminated?

 

Second: Are you using 'proper' DMX cabling or mic cable?

 

I :** laughs out loud **: use mic cables for some disco scanners and occasionally experience similar problems. Years ago I used to think it was the individual units, until I became better educated. I'm still using mic cables cause I can't be bovered to replace them all and it doesn't really matter for my purposes if the odd one coughs and splutters ;)

[Richard CSL]

the cables are already installed in the venue, so I am not sure of their type, however all the other scanners in the circuit work fine so for this instance I do not suspect the cable. (whatever it is) and no I have not put in a terminator at this stage until I solve the problem, as I feel sure this is irrelevant to this fault.

[chrismca09]

first stage in fault finding, never think anythings irrelevant! start from the ground upwards, why not try running in a loose DMX cable which you know that works on a single tie line I.e no links, straight to the input of your console.

[sleah]

the cables are already installed in the venue, so I am not sure of their type, however all the other scanners in the circuit work fine so for this instance I do not suspect the cable. (whatever it is) and no I have not put in a terminator at this stage until I solve the problem, as I feel sure this is irrelevant to this fault.

 

Richard, may I suggest taking up position behind the sofa? :** laughs out loud **:

 

You will soon be bombarded with "The terminator may be the MOST relevant to the fault". Seriously, DMX line faults can cause some rather unexpected results. For example it's highly likely that if reflections are occuring due to lack of termination, it will not affect all the units in the line, and will cause seemingly unrelated faults. Also even with identical units, some will be more sensitive to line faults than others. No particular reason for that, it's just life....

[Richard CSL]

OK on the line is 1 other GS2 and 2 DS3's. all work perfectly , no terminator. I have tried putting the dongle DMX 80' feed to the stage directly into this GS2, this produces stutter,

 

I will today put a terminator on the head to see if this solves the problem, but why does the other controller work perfectly, is the DMX signal over a shorter distance relevant, or is it the refresh rate of a 192 ch controller clearer signal than a full 512 ch computer dongle.

[greenalien]

When the Golden Scan 2 was a new device, a state of the art lighting desk was something like a Masterpiece 108, so the luminaire would only need to handle a relatively small number of channels in the data stream. DMX was a very new control protocol, and some of the timing in older units was somewhat slack. It looks like you may to run it off a desk that isn't sending a full universe of 512 channels.