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H96 Pro+ can't boot up - SOLVED (cold joints)

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    H96 Pro+ can't boot up - SOLVED (cold joints)

    I created my thread because I have different symptoms than in other threads and want to gather all information about my box here.

    From: GearBest (Alfawise store)
    Model: H96 Pro+ 3/32GB
    PCB: Blue V5 (LPDDR3)

    I'll write issues in chronology:
    1. On stock firmware it often restarts on demanding video/stream.
    2. Installed few apps and one similar to netflix, after watching some video it just truned off and it couldn't boot up in about 1h then suddenly started and worked as in 1st point.
    3. Created nandbackup with TWRP, updated to SCV7A, it was working great about 5h then again restarts on demanding video/stream.
    4. Then after few hours of rest it booted and worked fine for 2/3h then again restart.
    Actual state:
    It can't boot up when plugged the adaptor it just blinks once with blue led (on tv no signal).

    What I've checked:
    • Adaptor - seems working on other device, checked with multimeter and it's 5.28V, capacitors looks fine in eyes.
    • PCB - there're some sludge stains (too high humidity in store?) or maybe it's normal. Checked with multimeter the V and there is 5.28V on pins power supply, usb, leds etc.
    • USB power via cable - not working the same as with adaptor.
    • PC connection - no detect, no sounds etc.
    Strange thing:
    • I've warmed up the PCB with hand-dryer and it flash with red led. One time it was stable blue light but after unplugged the adaptor it returned to red.
    When I'll be back in home I'll try to check other things.


    Do you have any other ideas to fix it?

    EDIT:
    SOLVED!
    More details here.
    Last edited by majkool; 06-04-2018, 00:19.

    #2
    Again strange thing because I warmed up the pcb near power supply and one time it booted up and worked about 30 minutes!
    It must be something with capacitor like in that video: https://www.youtube.com/watch?v=UDo-aCmSfow

    Comment


      #3
      majkool

      Possible cold joint some where at the area between plug to ldo ic with info from the other thread.
      Did you change heatsink or use stock? This device can consume 6w + running videos. It pull 1A+ on ftmc playing video with 1 USB flash drive and 1 mouse receiver. I didn't check for benchmark. This means that maybe 5w is dissipate on that small heatsink. The restart probably due to overheat and as time go and due to the pcb also get hot, cold joint appear (solder weak due to heat and cool down) . Like you said, you don't have 1.8v so the problem should be around the ldo. Or the ldo itself

      Edit: report back if you have 5v and 1.8v on the ldo pin itself, not the pad. I will advice again or you can look below for a rough idea of what to test.

      In short, test on ic pin for vin vout
      Check capacitor connected to vin vout pin
      If ic no vin check vin side
      If ic no vout check vout side and supporting component.

      //end

      1) we have a timezone difference gmt +8.
      2) I dont use skype.
      3) whatsapp / wechat / line / fb /
      You only report back whether you have 1.8v or not. but I have no idea whether there is 5v powering the tx6211 or not.
      i assume with 5v and no 1.8v on ldo
      Please look at the image https://i62.servimg.com/u/f62/12/94/05/33/20180611.jpg
      1.8v ldo 5pin
      datasheet http://www.txsemi.com/Upload/TX6211B...1264794020.pdf

      edit: check for 5v on the 5v cap first(optional)If no 5v just remove the 10v 220uf first for easy testing since you suspect it failed(safe to remove and power on board). can always solder back. Get a tweezer/ long nose plier/ big flat head screw driver.
      example push capacitor in this direction >>>> you heat the solder pad on the left <<<<
      then switch to push capacitor <<<<<<<< and heat the solder pad on >>>>> right
      keep switching till cap fall off
      DO NOT use too much strength, board trace will tear/lift

      Always work with disconnected board when soldering.

      You check the 5v input to the tx6211 the one marked on pcb with an arrow and pointed in the picture(Vdd Pin 1 in datasheet)measure on the pin, not the solder pad

      ​​​​​Measure on the pin too
      If you get 5v, measure the output of the pin 5 label vout on datasheet. If you get 1.8v on the pin 5, test the capacitor circled in the picture and see if there is 1.8v If there is no 1.8v probably a cold joint somewhere that is connected to pin 5. easy fix.

      solution
      if have 5v and 1.8v on pin 5 but not at the capacitor
      melt the solder pad (circled pad or both ) for the 1.8v capacitor and pin5 pad and test again

      if have 5v but still no 1.8v on tx6211 pin 5
      remove the 1.8v capacitor the one circled and label 1.8v output. power on and test again on pin5 for 1.8v
      if still dont have
      disconnect power and melt all 5 pin solder pad and check for any pin bridge after soldering.
      Power on and see if it boot
      if boot, that capacitor is shorted.
      if dont, probably capacitor is good, connect back.

      If not booting, check for 5v and 1.8v on the ic pin.
      If still no 1.8v disconnect power and melt those solder pad that is connected to the resistor and capacitor surrounding the ic
      test again.

      If still dont have, touch up all the solder pad around picture marked out in red.
      if still dont have remove the 10v 220uf if it was not removed before all this test and test again

      report back for new solution since 10v 220uf is removed
      Pardon me if there are some sentences that dont make sense. Its 3:26am maybe i just cant think straight. Highlight to me so i can amend once im awake.
      Last edited by unrealistic; 06-01-2018, 13:26.

      Comment


        #4
        unrealistic

        Wow first of all thank you very much for your support in here! I'll for sure donate you a beer if you like to drink it.

        I've a whatsapp you could send me your nr on prv if you like that way but I see you wrote many options which I would for sure test it out now!

        About the photos it would be more helpful with names of the components on it (ido, tx6211 etc.) for now I know which is DC=E2H because can read it ;p

        What I have tested:

        Capacitor 220uf 10V = passed 5V on left pad which can be seen on photo
        Circle-arrow 5v input = failure 0V

        TX6211 aka LDO aka IC aka DC=E2H = passed 5V on VIN not passed on VOUT 1.8V

        How you call these ceramic 5V input and 1.8V output?

        On that black ic "5C w" there is on single pin ~5V but on the 2nd one "WT 1" there is 0V on output.

        Check that photo no voltage in lightblue squares: https://i.imgur.com/M54aA6X.jpg
        Last edited by majkool; 06-01-2018, 18:52.

        Comment


          #5
          majkool

          A picture speaks a thousand words. https://i62.servimg.com/u/f62/12/94/05/33/20180613.jpg
          Picture for you to draw https://i62.servimg.com/u/f62/12/94/05/33/20180614.jpg
          Red line is 5v tracks, green is 1.8v tracks

          LDO Low drop out regulator or linear regulator=dc=e2h=tx6211
          IC= integrated chip
          WT1 could be a diode or a pnp transistor/ mosfet. I bet it is a transistor but i not sure which model

          Things to do:
          measure
          label 1 pad for 5v - must have 5v
          label 2/3/4/5 pin for 5v - optional to test
          label 6 pin for 5v - optional to test
          label 7 WT1 pin for 5v - must have 5v
          label 8 pin for 5v - must have 5v
          label 9 pin for 5v - must have 5v
          label 10 pin and pad for 5v - must have 5v
          label 11 pin for 5v - must have 5v (you seems to have it)
          label en pin for 4.2v + may varies with device?
          label 12 pin for 1.8v
          label 13 pin and pad for 1.8v

          Label 11 to 13 is LDO area
          Label 1 to 10 is WT1 area where 5v is pass from label 7 to label 8 if there is no power in label 8, check label 8 and below pins / pad with discconnected power and continuity check them.

          Things to report,
          voltage list above. take note to measure pin or pad if both list both. copy paste list
          If as you said no 5v as marked by your blue box on label 9, then that nearest usb should not have any voltage too.

          Take care on tight space where you can short out pins like label 7/en if uncomfortable to do it due to probe being too fat, can dont measure. Need real sharp probe and stable hands. Tip. Pinky/ring/middle finger can grab the hdmi port side and slowly touch the positive tip to the pin and take a glance at the meter and look back on the probe slowly lift off.
          From here you can see which side go wrong.

          Resistor 0 ohm is acting like a fuse which only blow if very large current pass through
          resistor 4r7 is current limiting resistor for the LDO

          Always measure voltage on the component itself for example if it is capacitor or resistor , touch the top. For ic touch the pin leg side or top. Placing probe at solder pad give false info. Because the pin might have bad connection to the pad and is not getting power but you measured the pad which have power. So from now I will assume all voltage you get is from the pin.

          From start I thought that wt1 was powering the ldo but the trace was miss leading. You did a measure and I found that it was not connected. This board is more than 2 layer and the wt1 power passed to the unknown layer and provide power to unknown component.
          Dc e2h gets its power from plug I continuity measured it lolol. Seems to me it is a 3 layer board(for cost? Since 4 layer is more expensive)

          Edit, 1.8v powering passive component below the processor. Check your pcb bottom directly under the processor the whole cluster of capacitor and resistor for visible cold joint or shorts

          ​​​​​​​If is my board, I would just remove 10v 220uf and test if it power on and put back if it didn't boot up. If it boot I might replace it or won't even put one there. Much quicker than poking around. Normally if capacitor fails, it short out killing voltage to everywhere since electricity likes low resistance path. This is why some lcd tv have bad caps and replacing them make everything works so the dumpster diving people earn money. I never have a failed electrolytic capacitor before so can't say much. But I have a ceramic capacitor that goes short and boooom taking out resistors and diodes around it while appearing innocent with no visible sign of failure.
          Last edited by unrealistic; 06-02-2018, 02:21.

          Comment


            #6
            Thanks for clarification.

            Blue = pass
            Red = fail

            label 1 pad for 5v - must have 5v
            label 2/3/4/5 pin for 5v - optional to test
            label 6 pin for 5v - optional to test
            label 7 WT1 pin for 5v - must have 5v

            label 8 pin for 5v - must have 5v
            label 9 pin for 5v - must have 5v (I've 5v on all usbs, hdmi, sd card)
            label 10 pin and pad for 5v - must have 5v
            label 11 pin for 5v - must have 5v (you seems to have it)
            label en pin for 4.2v + may varies with device?
            label 12 pin for 1.8v
            label 13 pin and pad for 1.8v


            About the label 8,9,10, en voltage jumping from 0.00v to 0.01v and led just blinks once in blue after second check I don't know what changed that but it jumped to 0.15v and leds were flashing in red color.

            it's really hard for me to find the cold joints of processor capacitors/resistors from the bottom of pcb I've checked if there is voltage on them but there is no only in one place about ~0.5v.

            Look that video about the 220uf 10V capacitor: https://www.youtube.com/watch?v=UDo-aCmSfow

            EDIT:
            Found the place with issue so there must be somewhere cold joint on processors capacitors/resistors because I heated up them with hand dryer and it booted up and every time when it lose the power I heat that place again and works again!
            Last edited by majkool; 06-02-2018, 05:46.

            Comment


            • gefattern
              gefattern commented
              Editing a comment
              Hi , better to cool down your Box with Fan or better Heatsink , good luck / gefattern

            #7
            The main problem was the 1000uF 10V capacitor in the ac/dc adapter, I've changed it and now box is working like it should.

            unrealistic
            Thank you very much for your help!
            Last edited by majkool; 07-03-2018, 10:04.

            Comment


              #8
              Originally posted by majkool View Post
              The main problem was the 1000uF 10V capacitor in the ac/dc adapter, I've changed it and now box is working like it should.

              unrealistic
              Thank you very much for your help!
              Hi majkool I have exactly the same behaviour like you had. You wrote about replacing 1000uF 10V capacitor in the ac/dc adapter.
              Do you mean this one capacitor from this video? https://www.youtube.com/watch?v=UDo-aCmSfow?
              I'm not sure which one of them it is.

              Comment


                #9
                Originally posted by MarekM View Post

                Hi majkool I have exactly the same behaviour like you had. You wrote about replacing 1000uF 10V capacitor in the ac/dc adapter.
                Do you mean this one capacitor from this video? https://www.youtube.com/watch?v=UDo-aCmSfow?
                I'm not sure which one of them it is.
                Just change the adapter to new one because fixed one will be dead in few months like mine.

                Comment

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