Repairs to smart pixel strips

[BundyRoy]

Due to my lack of adequate support when mounting the strip last year I have damaged one pixel in my strip. The lights either side work fine. The lights in the non functioning pixel will come on if I squeeze the strip in the right place. I think it was if I pressed near the chip. How hard is this to repair. What's the tricks.

I've watched ShellNZ's vid on how to join a strip and I am reasonably confident I could cut the faulty pixel out and rejoin it. I would also be keen to have a crack at fixing the pixel if that is possible. The way I see if that failed all would have to do is cut out the pixel and rejoin it anyway.

What's the tips for cutting the silicon cover away without damaging the strip. As you would be more aware than me there are no visible wires running through the strip other than at the cut lines. Hence, why I have been loath to look around in there for a broken wire/join.

Can I determine which wire is broken with a multi meter by say measuring resistance between the join markers at each end of the pixel.

Any tips will be greatly appreciated.

 

[AAH]

You can cut the strip anywhere where the exposed copper pairs of pads are. Matt showed his preferred method of stripping the silicon at the Adelaide mini last here. He used a Stanley knife blade parallel with the strip and sort of just pierce the strip part way through and then sort of roll the harder sheath back and the internal silicon sort of balls up and can be removed pretty easy. Clean the copper pads up with something so that you get a nice bright surface and just solder the join up without applying too much heat.
An ink pen type eraser may be suitable for cleaning the pads. I've never used it but I do know that some people use them for cleaning dirty pads.

 

[BundyRoy]

Alan, I take it from your response there is usually no chance of repairing the faulty pixel.

After watching the repair video I was thinking the join would be a point of weakness or at least a point of limited flexibility. Do joins give any hassles.

 

[Kaden]

Alan, I take it from your response there is usually no chance of repairing the faulty pixel.

After watching the repair video I was thinking the join would be a point of weakness or at least a point of limited flexibility. Do joins give any hassles.

I have had strips fail "in the field" and fixed them by tightening a zip tie over the IC and wriggling it until the faulty connection was fixed.

I have also fixed a couple of strips by touching the IC's connections with a soldering iron to re-solder them, but more often than not it didn't work.

EDIT: Fixed probably the worst sentence I have ever written.

 

[ԆцряєсϮ]

To be honest theres a few things that could go wrong and each require different methods of fixing (Faulty solder joint, cracked track, faulty chip, faulty LED.
at around 40c a pixel its far more cost effective to just chop out and replace the faulty pixel.

 

[toozie21]

Due to my lack of adequate support when mounting the strip last year I have damaged one pixel in my strip. The lights either side work fine. The lights in the non functioning pixel will come on if I squeeze the strip in the right place. I think it was if I pressed near the chip. How hard is this to repair. What's the tricks.

I've watched ShellNZ's vid on how to join a strip and I am reasonably confident I could cut the faulty pixel out and rejoin it. I would also be keen to have a crack at fixing the pixel if that is possible. The way I see if that failed all would have to do is cut out the pixel and rejoin it anyway.

What's the tips for cutting the silicon cover away without damaging the strip. As you would be more aware than me there are no visible wires running through the strip other than at the cut lines. Hence, why I have been loath to look around in there for a broken wire/join.

Can I determine which wire is broken with a multi meter by say measuring resistance between the join markers at each end of the pixel.

Any tips will be greatly appreciated.

Which video are you referring to (I'd like to check it out)?

 

[BundyRoy]

Toozie, I don't have any video of my lights. They were a static display (well other than one rgb strip in a rectangle on random patterns) so would have been a fairly dull video. This year is going to be my first attempt at a coordinated display to music. Fingers crossed, it might be worth videoing this year.

 

[toozie21]

I'm just starting to take the plunge too, good luck!

I was actually referring to your comment amount "shellNZ's vid"

 

[BundyRoy]

Sorry Toozie. It was too early to be functioning properly. Video Here

http://auschristmaslighting.com/forums/index.php?topic=5518.0

 

[fasteddy]

I have fixed lots of strip in my time as i use a lot of strip in my display. All i do is cut the section out (beware that most times its the pixel that is running before the lights stop running that is the cause as the output of that chip has failed)

The process is fairly easy,

1: Confirm and cut dead section out
2: Clean solder pads on new strip section and strip you are repairing - ensure this is a very clean surface
3: Tin the copper pads with some solder
4: Fit clear heat shrink over strip
5: Solder new section in ensuring correct orientation
6: add a dab of silicone over the joins
7: move clear heatshrink over repaired section and shrink
8: clean of excess silicone and let dry

And now you have a durable weatherproof repair

 

[toozie21]

I have fixed lots of strip in my time as i use a lot of strip in my display. All i do is cut the section out (beware that most times its the pixel that is running before the lights stop running that is the cause as the output of that chip has failed)

The process is fairly easy,

1: Confirm and cut dead section out
2: Clean solder pads on new strip section and strip you are repairing - ensure this is a very clean surface
3: Tin the copper pads with some solder
4: Fit clear heat shrink over strip
5: Solder new section in ensuring correct orientation
6: add a dab of silicone over the joins
7: move clear heatshrink over repaired section and shrink
8: clean of excess silicone and let dry

And now you have a durable weatherproof repair

Nicely written up, thank you.


So you just use clear heatshrink as a silicone tube replacement for the new pixel? There isn't an issue of the PCB getting torqued while the tubing shrinks in on it?


Lastly, how do you determine which pixel is the issue? Scoping the Data line and seeing if it is coming out of the previous pixel IC?

 

[Kaden]

I have fixed lots of strip in my time as i use a lot of strip in my display. All i do is cut the section out (beware that most times its the pixel that is running before the lights stop running that is the cause as the output of that chip has failed)

The process is fairly easy,

1: Confirm and cut dead section out
2: Clean solder pads on new strip section and strip you are repairing - ensure this is a very clean surface
3: Tin the copper pads with some solder
4: Fit clear heat shrink over strip
5: Solder new section in ensuring correct orientation
6: add a dab of silicone over the joins
7: move clear heatshrink over repaired section and shrink
8: clean of excess silicone and let dry

And now you have a durable weatherproof repair

Nicely written up, thank you.


So you just use clear heatshrink as a silicone tube replacement for the new pixel? There isn't an issue of the PCB getting torqued while the tubing shrinks in on it?


Lastly, how do you determine which pixel is the issue? Scoping the Data line and seeing if it is coming out of the previous pixel IC?

I can answer this.

The heat shrink only covers the join you just soldered and siliconed, this should be the only part if the strip you exposed to repair it. You keep using the existing water protection on the strip, very little if any strain is put on the strip at the join from the heat shrink.


I don't have a technical way to diagnose the faulty pixel, I cut out the dead pixel and the pixel before it. Then you have covered both possible failures.

 

[BundyRoy]

What diameter heatshrink do you use to get round the silicon cover. Do people just buy heatshrink from local electrical store or is there a cheap online option.

 

[fasteddy]

From memory i think it was 12mm or 13mm.

It needs to be bigger than the strip. Heat shrink does vary also on it shrinking capabilaties so if i was using a 3 to 1 shrink then maybe a 16mm will do, using a 2 to 1 then 12 to 13mm

I bought mine from Ebay which was something like this
http://www.ebay.com.au/itm/Clear-13mm-Heatshrink-1-2m-Length-/390594956988?pt=AU_B_I_Electrical_Test_Equipment&hash=item5af1460ebc#ht_4134wt_1226

 

[ShellNZ]

I also use clear 12.7mm heatshrink. I dont just put a dab of silicon in there, I put oodles in there so when I heat it the silicon oozes out the sides That way I know its sealed