1. uraniumhexoflorite's Avatar
    My brother's Moto E4 is not charging or turning on. He said that the screen went black while he was using it and didn't turn on again. I have replaced the battery, tested the new battery with my multimeter to make sure it's not dead, used many different cords and adapters, and taken the phone all the way apart to make sure that there was no liquid damage. I also used a USB doctor to see if the phone was drawing current, but it was drawing only about 20 ma and drew around 200 ma for a short time when I try to turn it on. Has anyone else had this issue before? Thanks in advance for help and advice.
    08-18-2019 07:34 PM
  2. B. Diddy's Avatar
    Perhaps the USB port has failed. Was the replacement battery charged up before you placed it?
    08-19-2019 01:31 AM
  3. uraniumhexoflorite's Avatar
    Yup. 3.6 volts (lithium ion and polymer batteries like to be between 3.2 and 4.2 volts) and I recently replaced the charger board due to the charger port being damaged.
    08-19-2019 06:19 PM
  4. B. Diddy's Avatar
    Could it be the Power button/switch?
    08-19-2019 07:13 PM
  5. uraniumhexoflorite's Avatar
    I'm not sure. When I try and turn it on, the amount of current drawn spikes up to 200 or 250 ma, but then falls back down to 20 ma. Should I try re installing the old charger board to see if it works with that?
    08-20-2019 12:29 PM
  6. B. Diddy's Avatar
    Sorry, that's beyond my scope of knowledge. Let's see if @Rukbat has any ideas.
    08-20-2019 07:28 PM
  7. mustang7757's Avatar
    I'm not sure. When I try and turn it on, the amount of current drawn spikes up to 200 or 250 ma, but then falls back down to 20 ma. Should I try re installing the old charger board to see if it works with that?
    So you did more then replaced the battery ? You did the motherboard also? Sounds like your losing voltage somewhere , I would recommend letting a repair center fix it .
    08-20-2019 07:50 PM
  8. uraniumhexoflorite's Avatar
    I didn't replace the motherboard, but prior to the phone failing I replaced the charging board because my brother broke the charging port.
    08-21-2019 11:36 AM
  9. mustang7757's Avatar
    I didn't replace the motherboard, but prior to the phone failing I replaced the charging board because my brother broke the charging port.
    Oh ok, I would still take it in repair center get a 2nd opinion.
    08-21-2019 11:43 AM
  10. Rukbat's Avatar
    Yup. 3.6 volts (lithium ion and polymer batteries like to be between 3.2 and 4.2 volts) and I recently replaced the charger board due to the charger port being damaged.
    3.6 Volts isn't charged. It's not batteries "like" 4.2 Volts, it's that lithium polymer batteries under charge will show 4.2 Volts and will show between 3.7 and 3.5 Volts under use. By 3.2 Volts, the charge is on the way out.

    The battery (used one or new one) is about 2 years old (they make 2 loads of batteries - 1 before the phones are released, one a few months later), so find out why the charger board failed. That's probably where the problem is. Fix that, replace the "replaced" charger board if the problem took that one out too, then see what the battery does after 3 full charge/discharge cycles. (It's entirely possible that you got a defective battery off the shelf, too.)

    (The board that the charger port is on isn't the charger - that's a separate chip. The board that the port is on is just the board that the port [and I believe the buttons in the E4] is on.)

    If you don't know the cause, you can't fix it. Just replacing parts ... any repair shop can do that. If that's all you wanted, you could have brought it into one. Find the cause and fix it. Then replace any parts that the cause damaged.

    (Mustang's idea is a good one too - there might be a short on the motherboard, preventing the battery from getting charged. "Spiking" could be a bad capacitor. If you can find the bad one, replace it. [That wold require a current setting on the multimeter, removing capacitors one by one - the ones across the rails are best to start with, unless there's one with obvious damage - and watching each one with 5 Volts applied for spiking after the current settles down [to nothing - if it's leaking, replace it]. Repair shops, except for a few good ones, don't do things like that - they just replace the motherboard, instead of a 15 cent capacitor. Replacing a SMD capacitor requires desoldering and soldering, replacing a motherboard just requires a screwdriver, which most people think they know how to use.)
    08-21-2019 11:50 AM
  11. uraniumhexoflorite's Avatar
    The phone's original charger board failed because my brother yanked the cable the wrong direction and damaged the USB port. While 3.6 volts isn't fully charged, it isn't empty according to battery university's article about lithium ion batteries. I tried swapping in the old charger board and it didn't fix the problem. I doubt there are repair techs near me that will repair Motorola phones and my brother needs a new phone, so he may just need to get a new phone. I will open up the E4 again and take another look to see if I missed anything the first time.
    08-23-2019 04:35 PM

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