Control/Dimming What causes power cubes to fail?

[Brentgi]

I'm working with an ETC Smatpack Wallmount 10a 120v

Saturday night, while in service, three of the channels starting flashing, almost like a channel check but a bit more erratic in behavior. I've never really observed this before so I had to do a bit of research and it is all pointing to a power cube issue. I was also told that at least one or more of the cubes in this pack had already been replaced.

Here are my questions: What causes a failure in a power cube? And what are the best practices to keep this from happening (or at least slow it down)?

 

[JD]

3 Channels? Doesn't sound like a power cube. Basically a control or firing problem.

Anyhow, there are two main killers of Power cubes:
1) High current surge such as a lamp flashover or shorted cable. Most of the time, protection will save the cube, but if it goes, the channel will likely be stuck on full. (In rare cases they open, leaving you stuck at 0)
2) Heat. Usually this is an accumulation of years of thermal cycling, often exaggerated by poor ventilation such as clogged filters.
This second reason can leave a variety of symptoms such as flickering, cutting out, stuck full on, or stuck full off. It is caused by micro-stress cracks in the actual semiconductor junctions in the cubes.

Now, back to your original problem. I don't think it is your cubes (known also as SSR or Solid State Relay) and here is why- The thermal degeneration occurs over long periods of time, and varies from device to device depending on what has been on a given channel over the years. A heavy loaded and often used channel will fail before a lightly loaded and often unused channel. The thought that three of them would go the same night is pretty odd, short of some extreme heat event or a lightning strike.

Sometimes, some simple logic can be applied to narrow down the exact cause. For example, a unit that has six channels and runs off two phase legs, or 12 channels (some unused) running of three phase legs would indicate to me there may be a failure in the zero-cross detector for one of the phase legs (usually part of the CEM or it's equivalent module.) Problems in the CEM can also be heat, age, or water related. CEM problems are more likely to cause symptoms across multiple channels.

Last but not least, the actual DMX feed has to be ruled out as it can be a symptom wildcard.

 

[FMEng]

In addition to JD's list, I will add dead fans. Fans have a limited lifespan. It is pretty common to have to replace fans in electronic equipment that have died due to lubrication failure in the bearings. Heat, age, and dirt are contributing factors to fan failures. Nearing the high temp limits could certainly cause odd behavior. If it works OK for a bit after all lights have been left off for awhile, that would point toward a thermal problem.

 

[derekleffew]

Here are my questions: What causes a failure in a power cube? And what are the best practices to keep this from happening (or at least slow it down)?

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Keep your dimmers (and filters and fans) COOL and CLEAN.

Also, give ETC a call at 1-800-688-4116 as they may have some other ideas as to causes and solutions.

https://www.controlbooth.com/threads/ssr-failure-lee-colortran-dimmers-who-done-it.22081/
https://www.controlbooth.com/threads/ssr-failure.25874/
https://www.controlbooth.com/threads/etc-d20-dimmer-failure.13263/
https://www.controlbooth.com/threads/is-this-possible-lamp-failure-breaks-a-dimmer.11230/

https://www.controlbooth.com/threads/etc-smartpack-channel-problem.27855/

 

[RonHebbard]

I'm working with an ETC Smatpack Wallmount 10a 120v

Saturday night, while in service, three of the channels starting flashing, almost like a channel check but a bit more erratic in behavior. I've never really observed this before so I had to do a bit of research and it is all pointing to a power cube issue. I was also told that at least one or more of the cubes in this pack had already been replaced.

Here are my questions: What causes a failure in a power cube? And what are the best practices to keep this from happening (or at least slow it down)?

If memory serves; in those wall mount packs, I believe each SSR cube contains / affects four dimmers. By any chance are all three of your ailing dimmers within the same SSR cube? Also, are all three of your problem dimmers powered from the same phase? Is your pack powered by single phase or 3 phase?
Toodleoo!
Ron Hebbard.

 

[derekleffew]

@RonHebbard is correct.
https://www.etcconnect.com/Support/Articles/SmartPack-Dimmer-Output-will-not-Turn-On-or-Off.aspx

http://www.musson.com/q211-power-cube-for-smartpack-4x10a.html

 

[Brentgi]

3 Channels? Doesn't sound like a power cube. Basically a control or firing problem.

I'm 90% sure it's an issue with the power cube. Read below:

If memory serves; in those wall mount packs, I believe each SSR cube contains / affects four dimmers. By any chance are all three of your ailing dimmers within the same SSR cube?

You are correct. I should have clarified this. Also, the fourth channel was not active at the time so it was not exhibiting odd behavior.

In addition to JD's list, I will add dead fans. Fans have a limited lifespan. It is pretty common to have to replace fans in electronic equipment that have died due to lubrication failure in the bearings. Heat, age, and dirt are contributing factors to fan failures. Nearing the high temp limits could certainly cause odd behavior. If it works OK for a bit after all lights have been left off for awhile, that would point toward a thermal problem.

Once the lights have been powered-off, and the packs cool, the lights will generally work fine. The room that the equipment is installed in is set at a constant 65°F so that the equipment stays cool. However, I did not think to check the fans on the unit itself. I will do that first thing in the morning. Filters are kept clean.

Thanks everyone for the info!

 

[RonHebbard]

I'm 90% sure it's an issue with the power cube. Read below:



You are correct. I should have clarified this. Also, the fourth channel was not active at the time so it was not exhibiting odd behavior.



Once the lights have been powered-off, and the packs cool, the lights will generally work fine. The room that the equipment is installed in is set at a constant 65°F so that the equipment stays cool. However, I did not think to check the fans on the unit itself. I will do that first thing in the morning. Filters are kept clean.

Thanks everyone for the info!

If you strongly suspect all of your problems are in one power cube and want to prove it beyond a shadow of a doubt; if you're comfortable doing so, power down the pack, swap the suspect cube for one of your other cubes (interchange and reinstall both cubes), re-power and test. If your troubles have interchanged with the cubes you have your answer and your proof. Please post back. If you kill yourself following instructions from some random poster, me, I don't want to hear from your relatives.
Toodleoo!
Ron Hebbard