Sirius Memory/Output Failure

[Neil Hampson]

Had a very interesting desk failure last night, at 7.20, just after the house was opened.

 

I am using a Sirius24 (that I have have for almost 10 years now), with a DMX card control is Via a Demux48.

I had forgotten to plug in the litlelite, so as the audience walked in, I plugged in the light, immediately the desk began to 'pulse' several channels from 0-100% at around 1Hz, as the grandmaster was quickly pulled down, the 'pulsating' light effect also went ( I have no effects Programmed in). The desk seemed work OK in Preset mode, but as soon as a memory was called up either on the Go or to a sub-master, the pulsating channels came back. I wiped the desk and re loaded from the memory card, no change.

Luckily, being a school venue the school tech had an older desk that we could use for the night.

 

However, if you held onto the DMX cable plug of the Sirius (effectively Grounding the chassis), the fault went away, also when I got home I set the desk up to a DMX but could not replicate the fault at all.

Any Ideas? Could this be a grounding fault within the desk? have I popped an Eprom by plugging in the litlelite? if so why can't I recreate the fault at home? The only thing I can think of is that the DMX dimmer (Anytronics 610 Series) is more fault tolerant than the DEMUX48.

Any help would be appreciated, as I now need to work out if the desk can be repaired economically (if the fault can be found), whether it can be trusted in show conditions, or should it be replaced?

[Eric]

Best guess is a wyrd earth fault between desk and dimmer.

Plugging the lit lite in may be a red herring or it could be you nudged something that has developed a dry solder joint.

 

Something that it would be worth checking for is have a look at the 100ohm earth bond resistor on the PSU as if this is burn't out it will give you a good indication that you have an earthing problem.

[MarcT]

However, if you held onto the DMX cable plug of the Sirius (effectively Grounding the chassis), the fault went away, also when I got home I set the desk up to a DMX but could not replicate the fault at all.

I would also check that DMX cable,then the rest of the DMX run & termination.

 

Hope you get it sorted!

Marc

[Neil Hampson]

My first thought was a bad cable, but the cable runs no problem with the schools desk. I thought that I had blown a component due to a power surge generated by plugging the lamp in, but now that I can't replicate the problem I'm pretty much stuck. I have a fully working desk, but can I trust it not to do it again???

 

Not that electronics is my thing but, If a power surge has corrupted an EPROM or similar controller, is there a memory effect that having the desk off for several hours would reset the fault?

 

There are other things that just don't stack up;

 

1 ) The install works fine with another DMX desk; pretty much rules out any downstream faults (Cables / Demux / Dimmers etc.)

 

2) I can Save the whole memory from the suspect desk to another Sirius, and there is no data curruption; So I can't see a failure of the memory section of the desk.

 

3) Analogue outputs appear to be unaffected; supporting the DMX card failure.

 

4) DMX transmition is error free when using 'Preset only' mode; Rules out DMX failure.

 

5) The whole thing worked when you held onto the DMX connector.

 

6) It works now, sat on my kitchen table (much to the annoyance of my wife) when connected directly to DMX dimmers.

[jayselway]

2) I can Save the whole memory from the suspect desk to another Sirius, and there is no data curruption; So I can't see a failure of the memory section of the desk.

 

Could you not use this other Sirius for the rest of the show, then maybe investigate the problem when there is no show on to worry about? Just a thought....

[Neil Hampson]

Could you not use this other Sirius for the rest of the show, then maybe investigate the problem when there is no show on to worry about? Just a thought....

 

I am using the school's Sirius for the remainder of the run, although the state it's in you wash your hands after using it rather than before, its missing a lot of its control knobs and stuff and the faders are a little stiff and shakey but at least the go button works, oh and when the faders are pushed up past 95% to full, they flash off on the way up.

 

The point of my O.P. was to try an find out what could be wrong with the desk so that I can work out how best to fix it. Obviously at the tech desk, with the FOH manager svreaming at you is not the best environment to repair a desk.

[si_cole]

Hi

 

I had something similar with an Illusion120 by Zero88. It was down to the desk lamp. Cant quite remember all the details but it was something like the grounding of the lamp was different to the manufacturers spec and so was suing the desk to ground, thereby causing the desk to reboot all the time.

 

I swapped the lamp, worked fine.

 

HTH

Si

[jayselway]

Thinking about it, I'm fairly sure I had a similar problem with a Q Commander - where the desk lamp went in and rebooted the desk. Tried a different lamp. However, 2 years on, the power supply went *poooof* during a club night. :D

[noelsparks]

Sounds obvious :D but I suspect you have a dry joint on the DMX 5 Pin XLR Connector Socket on the back of the desk - if it works when you hold it you're probably mving the socket inside sufficiently to make contact with the PCB so check the solder connections to the plug.

 

If this fails - recheck the desk and see if holding the DMX plug still cures the problem - if so replace the socket and may be the plug as well if theres any sign of corrosion on the pins. :(