LED Walls

[the kid]

I am wondering, people who own led panel.

 

How big are the pixels ?

 

Do you expect issues, namley pixels dying (or a colour on a chip) ?

 

Do you encounter other damages ? what does that look like and how often ?

 

Thanks, I think more questions might come up as they are answered.

[david.elsbury]

We’ve just purchased a p2.6 (2.6mm) wall from China. Been out on a couple gigs so far. Each panel (0.5m x 0.5m) has 4 modules that are individually replaceable so if you have a dead pixel or whatever it’s easy to remove that module and swap, and deal with the fix later.

Have noted a couple of receive module issues where a line of pixels dies or goes one colour.

 

With panels this small pitch the LEDs are tiny and (obviously) right on the edge; that’s where they are most likely to get damaged.

[indyld]

With a name brand such as something like Martin P3 / VDO panels and under warranty , there is a process for swapping out sub-panels with a dead pixel under the warranty.

Once out of warranty, then it's 'buy a new part', just like any other bit of kit. Again, with a name brand there is gonna be some commitment to keeping parts available which is forms part of the purchasing decision.

 

I've not had to look into rework of individual LEDs yet but given the process of manufacture and the difficulties with even larger LEDs on movers, I imagine that this isn't gonna be much of an option for your average repair bench. The speed at which the edge pixels fail also can be related to how skilled your crew are at building the screen. There is a bit of a knack to mating adjacent panels and keep mechnical stresses low.

 

Like all kit, the better it's boxed and more carefully it's used, the slower the deterioration. At pixel level, a fault usually shows up as a missing colour during testing. On return from a hire, each panel is cleaned and physically checked, then run through the colours with a visual inspection for dead pixels. The ones on the edges are hardest to spot but also the most common failure. Pro tip: turn the overall brightness down to make visual inspection easier and less fatiguing.

 

Of course, that's all fine and dandy in the warehouse. On site, a box of spare modules and some vertical access capability is the way forward. A friend of mine is a screen specialist on large RnR tours and there seems to be a lot of abseiling involved in the daytime haha. You can generally remove a module in place even in the middle of the screen although it can be a bit fiddly. They are held in place with various systems including magnets in some.

It's common practice to add panels during the screen build while a test signal is running, allowing the crew to spot problems as the screen is built. The panels and modules are hot swappable and kinda come 'online' once plugged in and they've worked out where they are.

[Pete McCrea]

So I own 6mm outdoor and 3.9mm and 2.6mm indoor products. The 6mm is an 0.8m x 0.9m ‘cabinet’ or panel which then has 8 ‘Inteligent Modules’ or IM’s that contain the LED chips, with the 3.9mm and 2.6m both being 0.5m x 0.5m panels and having 4 IM’s per panel. Pixel sizes depend on the diode package chosen, and of course the resolution as that will determine how close together they need to be.

 

You will get failures. Physical damage where the smd’s are physically knocked off or the joint goes dry, and then electrical where one diode in the package might fail, so you loose the colour. Sometimes a driver chip will fail and this tends to be where you see a column of one colour stuck on. We built a 5m x 3m screen today out of the 2.6mm and I think we had one dead pixel out of 2,211,840 smd’s (each with an r, g,b diode, so if you multiply it by three it’s even lower) so as a percentage it’s quite low. If it’s a dry joint (giving it a poke often gets it working) then we’ll reflow the solder in house.

 

Physical damage can be the worst - we had a panel of 2.6mm dropped by an over enthusiastic helper in January which damaged all four of the IMs and wrote one off completely as the tracks in the pcb were shot to pieces on the corner, and as they’re multilayer boards it was beyond repair. The chassis is ok so we’ll re populate with spare IM’s, but it does mean we’re now lower on stock of spares.

 

When onsite we’ll carry spare IM’s and other components and swap them out if needed, so we don’t have to remove the cabinet from the wall.

 

And yes access can be a pain - the chassis on our 2.6mm is rated for climbing if needed.

 

We also repair dead pixels on the 3.9mm and the 6mm. 6mm is harder as it has a sealing compound around the smd’s due to up rating. Our 2.6mm is still in warranty so they get done by the manufacturer. Part of buying a screen is ensuring you get sufficient spare components such as the LED’s and driver IC’s so you can swap them with batch matched components ideally.

[the kid]

 

 

When onsite we’ll carry spare IM’s and other components and swap them out if needed, so we don’t have to remove the cabinet from the wall.

 

 

 

what % spares do you carry ? is it 1 case for 1-10 cases 2 for 10+ or a % per hire?

[indyld]

Interesting that you are doing repair and reflow in house, Pete. I've not had to do that yet but no doubt it will hit the bench once the warranty is up.

 

Luckily SMD work is now part of the routine due to the way modern moving lights are. Anything fixable with a hot air station is within scope.

 

Will be a new thing to look forward to. :)

[empyfree]

We tend to round up to full cases to give us some spares. Then take a look a the overall amount of panels and make a decision to take another case of spares as well. We don’t bother carrying loose modules or “brains”, rather either swap out an entire panel or rob bits from a spare.

[Pete McCrea]

Spares - we’ve found our products to be very reliable. I think I’ve had one psu fail in our 3.9mm in 4.5 years (Meanwell supplies), not aware of any going in our 6mm. The 2.6mm has an easy to swap psu/receiver card unit that has 4 catches, so easy to carry those.

 

But yes we round up to full cases typically and then maybe a few IM’s, hubcards, psu’s Etc.

 

The repairs aren’t too hard. As you say with a hot air re-work station and magnifying glasses it’s perfectly possible to solve most of the problems.