LED wall - dead pixels from lack of use?

[Stuart91]

One of our clients bought an LED wall last summer. They only operate it seasonally, so it has been sitting unused since early autumn. 

Last week we powered it up for the first time in a few months. There is now a noticeable amount of dead pixels, a quick count suggests that roughly 1/4 of the panels will need swapped out. 

A complaint has been raised with the manufacturer. Their response is that the panels shouldn't be left unused, and the inrush of current after the downtime is what could have caused the damage. They recommend running the screen for a minimum of eight hours a week. 

The client is getting hammered by energy bills so won't be happy running with that prospect (although it's cheaper than replacing panels every season). What's probably going to be more irritating is having to roster a staff member to go in and deal with it when the venue isn't in use. 

What I'm wondering is if this is a common requirement? I've not come across it before, although we have only really dabbled with LED up until now. Whilst rental companies aim to keep their stock busy working, there must inevitably be gaps in the diary - and what did people do during covid?

[DrV]

I wonder if the issue is not inrush current but moisture ingress. When the panels are on they will be keeping warm and dry but if they are off for long periods then it is possible that moisture is entering through the seals on the individual LEDs. If the issue really were inrush current then they would be admitting to a very poor design which allowed the mains inrush to create a transient on the (electrically distant) LEDs.

What is the temperature and humidity like during downtimes?

[CallumP93]

One of the LED manufactures we have used in the past released this guidance following COVID-19 lockdowns with regards to turning screens back on.

https://www.digiled.com/tom-mudd-advises-on-how-to-bring-your-digiled-screens-out-of-hibernation/

Generally after long periods of non-use / storage they recommends starting the wall at low brightness to 'dry' out the LEDs before going up to full brightness.

We have definitely seen failures on outdoor products when left off as the product cools down and water always seems to get where you don't want it.

[Stuart91]

6 hours ago, DrV said:

What is the temperature and humidity like during downtimes?

Not sure about the humidity (although I've got a meter on order from Amazon at the moment). 

It's essentially an unheated warehouse - pretty poorly insulated. This time of year you can see your breath in front of your face. However there was no sign of any moisture on the panels, and the room in general seems dry.

[Stuart91]

1 hour ago, CallumP93 said:

Generally after long periods of non-use / storage they recommends starting the wall at low brightness to 'dry' out the LEDs before going up to full brightness.

We have definitely seen failures on outdoor products when left off as the product cools down and water always seems to get where you don't want it.

That's very useful. The first thing we did was run a test pattern from the controller, which may not have been ideal. I'll need to check the manual, but suspect it bypasses the brightness controls and runs the patterns at 100%. (Certainly seemed that way)

It reminds me of ye olden days when it was important to preheat your filaments rather than slamming a lighting rig on to full brightness.