WPJ344-LV low voltage on +5VDC and +3.3VDC rails

  1. 4 months ago

    Hi guys,

    We had 2 x WPJ344-LVs lying around and I recently bought 11 more for a project; we were having a real tough time with USB and mini-PCIe (both OpenWrt and LEDE) and I simply could not figure why.

    Eventually we got to testing the voltage levels of the two pertinent rails, only to find that they were quite low:

    +5VDC rail was measuring about +3.3VDC (interesting)
    +3.3VDC rail was measuring about +2.5VDC

    We tried two different +24VDC power supplies and 1 +12VDC power supply (all with the ability to provide enough current) and the results were the same.

    We confirmed that we could get USB working by pulling up the +5VDC rail towards 5V manually with a reliable +5VDC source, we didn't try with mini-PCIe though (didn't wanna blow up our expensive LTE cards).

    Interestingly, this issue was in play with our older boards and our newer boards.

    All boards were bought from 524wifi.com

    Has anyone seen an issue such as this?

    One of new board serials is 104030475, one of the old board serials is 103232568.



  2. 3 months ago


    Feb 10 Moderator

    Hi Ed,

    Thanks for bringing up this bug to our attention. Please find the fixed firmware here:

    USB VCC default is set to 5V by setting GPIO13 as output value 1.

    If 802.11ac wireless card is used, the temperature switch feature may set the output back to 3.3V if the card is very hot. This has been encountered in the WLE600V5-27 and WLE900V5-27 cards. To disable the temp switch feature, run:

    uci set wireless.wifi1.tempswitch=0
    uci commit wireless



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