LED lights in channel letters

[Stormyj]

Hi all,
Ive been called to fix a channel letter sign that has LED light modules not working. When I took off the cover, I found the normal strings of 12vdc LED modules with some on the string lit, some very dim and some not lit at all. I thought immediately that the strings were just going bad from being in the elements. I did not check the power supply because it is in the attic of the building with little if any access, (they boarded up the access). My question is, am I correct in assuming that the modules are just going bad and need to be replaced or could it be the power supply. I think normally when a power supply goes bad, it simply quits and does not provide low voltage thus dim lights and some not lit. i would like to get some feed back before I spend the $200 on LED modules. Thanks all
Jim

 

[Biker Scout]

Rats chewing on the wires in the attic.

(Why would you spend so much on LED modules?)

 

[Z SIGNS]

To service illuminated signs you have to understand the theory of trouble shooting

Led channel letters are a no brainer.

There are only 4 things that could be the problem.
I will let the experts chime in as to what they are.

In the end it's up to you to as a serviceman to sleuth it out.

 

[signage]

You are aware what the saying is about assume (Assuming)!

Being a service person is not guessing but trouble shooting! If you do not know what you are doing then hire a true sign service company.

 

[Stormyj]

Just asking for opinions. $200 is for roll led modules. Thanks for input.

 

[Signsforwhile]

When taking service calls the only way to make money and keep the customers costs reasonable is to have a properly stocked service vehicle.

This means having one or two power supplies on hand and at least some LED no matter what the color. This way you can start isolating things. You can connect the bad letter to your good power supply and see if it works or not.

Also not having access to the power supply is a code violation. All electrical junctions need to be accessible for this reason. I would make your customer aware of this. It's another service you can provide for them and get paid for.

 

[Stormyj]

When taking service calls the only way to make money and keep the customers costs reasonable is to have a properly stocked service vehicle.

This means having one or two power supplies on hand and at least some LED no matter what the color. This way you can start isolating things. You can connect the bad letter to your good power supply and see if it works or not.

Also not having access to the power supply is a code violation. All electrical junctions need to be accessible for this reason. I would make your customer aware of this. It's another service you can provide for them and get paid for.

That is what I was looking for. I didnt think about the code violation. I know it is, just didnt think of it. I checked voltage coming out to led modules and got 12v so ill hook up a new mod or string and see how it works.
On another note, using the word "assume" on this forum? My gosh, its handing out ammo and asking to get flamed. What was I thinking.

 

[Biker Scout]

How many LEDs on are said "roll"? 100? At the very least you are paying twice as much as you should. And the real large channel letter shops get 100 LEDs for a tenth of price still.

 

[visual800]

Damn! Who are you getting your leds from? I get mine from tubelight and they are great lights but I dont spend that much for lights and power supplies

 

[Stormyj]

Ill check out tubelite, I get mi e from earlmich.com a I get 4 modules per ft 50 ft for 200. Ill have to reevaluate.

 

[Biker Scout]

What do you need in an LED module? 5050 SMD Chips? UL Listed? IP68 water resistance rating? Those are practically a dime a dozen now. Seriously, you gotta shop around.

 

[MikePro]

Overthinking this. If there's lit modules, then it is safe to "assume" that the power supply is working. You're most likely dealing with bad modules or bad wiring between modules. Cheap LEDs will quickly corrode outside, due to exposure to elements/moisture while the power supply operates in ideal conditions inside its enclosure inside of the building.

 

[Stormyj]

Ok. So after looking at the led modules in the letters, some were lit others were not. These leds were in the letters for little over 7 years, so replaced with new modules. Letters are still dim, but all are lit now. Checked voltage going to driver and found 120v with out put, while connected to leds, 6v. removed driver and checked without load, 12v. I was going to order new driver, the're $30. Driver was not warm while connected to leds. It seems that when there is a draw on driver, it starts to fail. Is that right? All the leds are connected in parallel. I dont think that there is a wiring problem since all letters are lit. If there was any wiring done backwards, they would be out, or the ones that are backwards anyway. What you guys think.

 

[Techman]

I think a course in DC voltage and wiring electronics is in order get your confidence up.
I obtained a 60 watt power supply for about 27 bucks from wensco. That could give you an idea on the cost.

A while ago I got a roll of LED lights with three bulbs per module for about a buck a module. Recently I obtained about 30 ft of waterproof LED strips for for about 10 bucks. So the price of these units is way down.

There is/was a vendor here that sells them for a very low cost. He sent me some samples and they are excellent.
signworldusinc
http://www.display-wholesale.com/servlet/the-LED-Sign-Modules/Categories

 

[Stormyj]

I think a course in DC voltage and wiring electronics is in order get your confidence up.
I obtained a 60 watt power supply for about 27 bucks from wensco. That could give you an idea on the cost.

A while ago I got a roll of LED lights with three bulbs per module for about a buck a module. Recently I obtained about 30 ft of waterproof LED strips for for about 10 bucks. So the price of these units is way down.

There is/was a vendor here that sells them for a very low cost. He sent me some samples and they are excellent.
signworldusinc
http://www.display-wholesale.com/servlet/the-LED-Sign-Modules/Categories

Actually I got a roll of 100ft with 2 mod per ft with 3led per mod for $1 a foot. And yes, I have some knowledge in electrical, but not with these components. Not sure of how they act alone or under load, how they normally fail, etc. My main problem now is above with the power supply/driver
Anyone else??

 

[visual800]

We were asked to service a sign exactly like you are referiing to. Some lit, some dim and they were off brand cheap leds, swapped them out with power supplies and it was lit up!