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Thread: Issues with 2x power supply LED strips setup - only half lit & randomly turns off?

  1. #1
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    Default Issues with 2x power supply LED strips setup - only half lit & randomly turns off?

    Hi all, long-term lurker, first time poster. I started working with LEDs about six months ago and learned a lot from this forum, and now I'm neck deep in my first major build. As expected, it's time for some troubleshooting .

    The installation is ~35' of 5V WS2812B addressable LED strips in aluminum diffuser channels around the ceiling of our home office.

    Here's my schematic:
    LED Strips Schematic - Office Ceiling (v5 - wire wrap) hide text (small).jpg

    And here's where I'm currently stuck:
    Office LEDs - full room test half lit (v2) small.jpg

    As you can see, only half the installation lights up (i.e. the west wall and half of the south wall, if you refer to my schematic). This section is driven by a 200W power supply ("PS1") and an SP501E controller. PS1 is also wired to power the north wall, but I'm guessing that the signal isn't making it all the way around to that point.

    The lights stop at the point where there's a break in the strip, in the middle of the south wall. This break is where PS2 takes over with the VCC line (as it's my understanding that one shouldn't connect the VCC lines of two different power supplies). Meanwhile, the data and GND lines flow from PS1 in the northwest corner counter-clockwise all the way around the setup. To avoid a ground loop, I did not wire the end of the GND back into the circuit.

    Here's a gallery of close-ups of my wiring for all four corners and the south wall break: https://imgur.com/gallery/kJeGGOu

    One other thing I should mention - when I first hooked up everything last night, the western half lit up, but then immediately turned off after a few seconds. I tried this many times over the course of an hour - every time, the lights stayed for between 2 and 15 seconds before turning off on their own. My guess was that PS1 was being overloaded for some reason, and a thermal throttle/auto shut-off kicked in to prevent damage to the supply. HOWEVER, when I tried again this morning just for kicks, the lights were suddenly able to stay on for much longer periods - 1 minute, 2 minutes, 5 minutes - before shutting off. As of now, the lights have been on for more than 30 minutes with no issues, and PS1 is barely warm. Literally nothing changed setup-wise between last night and this morning, so I have no clue why the lights seem to have gotten progressively more stable on their own.

    At any rate, I've completely exhausted my EE knowledge and troubleshooting ideas at this point and would really appreciate any advice you guys can offer.

    Here are a final few notes for your reference:
    • PS1 specs: 5V 40A (200W); max load = 123W
    • PS2 specs: 5V 20A (100W); max load = 72W
    • The primary VCC and GND lines (thick red and black wires) = 10AWG
    • The secondary VCC and GND injection lines (thin red and black) = 18AWG
    • The data lines (thin green) = 20AWG
    • All the strips are correctly oriented for data to flow in one direction
    • I'm ~90% confident in the integrity of all my solder points (I took it slow and double checked their strength before coating with hot glue)
    • The wire connection points that are wrapped in tape are all twisted tightly together (these are meant to be temporary so we can install the walls modularly)
    • I measured the output voltage of PS1 and PS2 with a multimeter and got 5.03V for both of them
    Last edited by Infinite Entendre; 07-01-2021 at 09:55 PM.

  2. #2
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    Default Re: Issues with 2x power supply LED strips setup - only half lit & randomly turns off

    When you say ON do you mean they are running a pattern?


    2021 New Tune-to sign. New 40x27 matrix at the house. Retiring the Strip based matrix. Updating some of the old window frames to the new house. Adding two new songs.
    2020 Full sized show reworked for the new location. Only adding (famous last words) 13 RBLs that I finally got converted to using pixels
    2019 - Just moved into a new home (yet another change of plans). Will be dim but not dark. Too much to do at the new place to leave time for a show. Dim show (3000 pixels) had regular visits most nights.
    https://www.youtube.com/user/MartinMueller2003

  3. #3
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    Default Re: Issues with 2x power supply LED strips setup - only half lit & randomly turns off

    Quote Originally Posted by MartinMueller2003 View Post
    When you say ON do you mean they are running a pattern?
    Yes, a simple pink and blue chasing effect that I selected from the controller's Android app:

  4. #4
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    Default Re: Issues with 2x power supply LED strips setup - only half lit & randomly turns off

    Re watch your video !!! You have captured the gremlin clearly , under the table

    Are all V- tied together ?

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    Default Re: Issues with 2x power supply LED strips setup - only half lit & randomly turns off

    Hahaha yes, I see her now, little bugger!

    Yep, V- is all tied.

  6. #6
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    Default Re: Issues with 2x power supply LED strips setup - only half lit & randomly turns off

    I am guessing it could be a burnin anomaly . I'd let them run for 24hrs

    I have experienced some strange behavior with Ws2812b strip that I have cut up into 92 strips of 84 pixels each.
    They were installed into a matrix from brand new and used for one xmas season .

    I have since repurposed some of them. Sometimes the repurposed strip just will not initialize on first attempt , its as if the pixels
    have retained their prior position channel data or something odd like that . Some are more stubborn than others and take several attempts to
    initialize or will initialize a few pixels at a time until finally the entire strip is light .
    Last edited by angus40; 07-02-2021 at 01:14 AM.

  7. #7
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    Default Re: Issues with 2x power supply LED strips setup - only half lit & randomly turns off

    I figured it out - it was the solder points on that gap in the south wall. The 18AWG wire I'd been using for splice lines is really just a bit too thick to solder directly onto strips. I removed those and soldered in 20AWG splices lines instead. Turned it on and it worked:
    Working strips.jpg

    Thanks for the help guys!

  8. #8
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    Default Re: Issues with 2x power supply LED strips setup - only half lit & randomly turns off

    Quote Originally Posted by angus40 View Post
    I am guessing it could be a burnin anomaly . I'd let them run for 24hrs

    I have experienced some strange behavior with Ws2812b strip that I have cut up into 92 strips of 84 pixels each.
    They were installed into a matrix from brand new and used for one xmas season .

    I have since repurposed some of them. Sometimes the repurposed strip just will not initialize on first attempt , its as if the pixels
    have retained their prior position channel data or something odd like that . Some are more stubborn than others and take several attempts to
    initialize or will initialize a few pixels at a time until finally the entire strip is light .
    The pixels do not retain any data nor do they know their position in a string of pixels. Each pixel simply consumes the first 24 bits it receives and sends anything else it gets on to the next pixel in line (often called a consumptive protocol). The most common problem is poor data / data reference (aka V-) issues that cause a pixel to fail to recognize changes on the data line as valid data. The timing on the data line is pretty tight so it is sensitive to external noise.


    2021 New Tune-to sign. New 40x27 matrix at the house. Retiring the Strip based matrix. Updating some of the old window frames to the new house. Adding two new songs.
    2020 Full sized show reworked for the new location. Only adding (famous last words) 13 RBLs that I finally got converted to using pixels
    2019 - Just moved into a new home (yet another change of plans). Will be dim but not dark. Too much to do at the new place to leave time for a show. Dim show (3000 pixels) had regular visits most nights.
    https://www.youtube.com/user/MartinMueller2003

  9. #9
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    Default Re: Issues with 2x power supply LED strips setup - only half lit & randomly turns off

    Quote Originally Posted by MartinMueller2003 View Post
    The pixels do not retain any data nor do they know their position in a string of pixels. Each pixel simply consumes the first 24 bits it receives and sends anything else it gets on to the next pixel in line (often called a consumptive protocol). The most common problem is poor data / data reference (aka V-) issues that cause a pixel to fail to recognize changes on the data line as valid data. The timing on the data line is pretty tight so it is sensitive to external noise.
    I wish there was a simple explanation for the anomalies I have experienced with these strips.

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