Tech tip - 3M Scotchlok (AKA jelly beans, Beanies, UR or ULG) - and a warning

[k6ccc]

For years, once the show is up, if I had a pixel die and it was near ground level, I would properly solder in a replacement pixel.  However if it was high enough that I needed to use a ladder, I would generally use 3M Scotchlok ULG connectors (also known as jelly beans, or beanies, and a few other names).  For those that are not familiar with Scotchlok connectors, they are a insulation displacement connector that are filled with a waterproofing gel.  The are or were used by the billions by phone companies for splices in the field.  You slide two or three wires in, and crimp with a pair of pliers - there are "proper" tools, but pliers work fine.  Very fast and very reliable - and a heck of a lot easier to use on a ladder than a soldering iron.  They are available in several sizes depending on the wire size.  Because of the insulation size, the ULG size generally works well for most pixels.

Now for the warning part.  I was doing some repairs in my pixel tree yesterday up near the top, so out came the ULG connectors.  I had all kinds of problems with pixels downstream of the repair not working right.  Finally a light bulb came on and I measured the voltage at the end of the string - 1.8 volts.  Cut out one of the sets of ULGs and stripped and twisted the wires together and back to 4.9 volts and the pixel test pattern was working.  ULG connectors are intended for 19 AWG wire, but these pixels had about 26 or 28 AWG wire - a fact that was not obvious until I stripped the insulation off.  So because of the tiny wire size, the ULG was not making a decent connection.  The insulation was about normal for most pixels wires - and barely fits into the ULG connector, so I could not use a Scotchlok for smaller wire size. 

If you are not familiar with these connectors, here is a link so you can see what they look like:

https://www.anixter.com/content/dam/Suppliers/3M/Products and Application Guides/3m-scotchlok-connectors-and-tools-brochure.pdf

 

[Orville]

Good to know, Jim.  I use those sometimes too for a repair.  Will find a different connector for a "quick" in-the-field repair for a pixel strand that may have issues with a bad bulb.

 

[TheDucks]

Ive used these (used by security installers) https://www.elkproducts.com/product/white-gel-filled-b-connectors-wire-splices-ul-listed-9022/

They also have non gel versions.