Hints on how to proceed - Aspire 7 - A715-72G-739V doesn't boot

2

Answers

  • northland
    northland Member Posts: 30

    Tinkerer


    Jack:
    Proceeded as follows:

    - removed RAM and HDD doors
    - removed HDD cradle and disconnected
    - removed back cover
    - disconnected battery from main board
    - reassembled
    - applied AC power
    - same repetitive cycle outcomes as before





  • JackE
    JackE ACE Posts: 45,202 Trailblazer
    Shoot!!! Sorry, I forgot to ask you to check the coin cell voltage with a multimeter while you were in there and had it out. It must measure well over 3volts open circuit. The fact that F2 doesn't get you into the BIOS menu further suggests its the root of the stuck-in-sleep/hibernate-mode issue. Jack E/NJ 

    Jack E/NJ

  • northland
    northland Member Posts: 30

    Tinkerer

    Thanks for the further response.   
    Next challenge?   No multimeter.    Shall see what I can do.
  • northland
    northland Member Posts: 30

    Tinkerer

    Hmmmmm ... upon reflection your last reference to coin cell voltage has me second guessing myself.    In the last test cycle was it the main battery pack I was to have disconnected from the mother board - or - the coin cell battery?
  • JackE
    JackE ACE Posts: 45,202 Trailblazer
    That's correct, the main battery pack. Might as well leave the pack disconnected to eliminate it as a possible cause or contributor. I'd like to see us get into the BIOS menu by pressing and holding the F2 key in the off state, then press the power button  Jack E/NJ

    Jack E/NJ

  • northland
    northland Member Posts: 30

    Tinkerer

    Managed to get hold of an old analog multimeter.    Tested it first on new AA and 9 volt batteries and it seemed reasonably accurate.   Disassembled machine again and checked the coin cell voltage.    It appears to be approximately 3.2 or 3.3 V.

    Reassembled and, just for sport, applied AC and sought to start the unit again with F2 depressed before power on.   Same repetitive cycle.
  • JackE
    JackE ACE Posts: 45,202 Trailblazer
    Try this with the machine off. Press & hold ALT+F10 keys, then press the power button to turn it on. Same result? Jack E/NJ

    Jack E/NJ

  • northland
    northland Member Posts: 30

    Tinkerer

    Same result.
  • JackE
    JackE ACE Posts: 45,202 Trailblazer
    With the machine off, press & hold a bunch of random keys with your palm and fingers, then press the power button. Do you even hear a BIOS keyboard error beep code? Jack E/NJ

    Jack E/NJ

  • northland
    northland Member Posts: 30

    Tinkerer

    No keyboard error beep evident.
  • JackE
    JackE ACE Posts: 45,202 Trailblazer
    Need to open it up again. Re-seat the two KB connectors and anything else you can reach while you're at it. Jack E/NJ


    Jack E/NJ

  • northland
    northland Member Posts: 30

    Tinkerer


    Actual circuit layout does not appear to match image you shared.   Image below shows empty battery connector on the left and single (presumably) keyboard connector (with black ribbon cable attached) on the right.    Ribbon cable appears to be secure.

    Also checked other evident connectors and all appear to be secure.

    Did not close up and retry pending your feedback on diagram to actual delta.




  • northland
    northland Member Posts: 30

    Tinkerer

    P.S.
    Got a magnifying glass and legend on mother board does show JKB1 and JKB2 both over top of single ribbon connector.
  • JackE
    JackE ACE Posts: 45,202 Trailblazer
    >>>Ribbon cable appears to be secure.>>>
    Pull it off. Push it back in. Pull it off again. Push it back in. Repeat a half dozen or so times to try to clean the internal contacts. You may have to gently rock it back and forth side to side as your pulling to get it to come out. Same with all the other accessible connectors. Jack E/NJ

    Jack E/NJ

  • northland
    northland Member Posts: 30

    Tinkerer


    Did the repetitive cable detach / secure process for the keyboard cable and every other cable connector I identified.    No joy.   Same outcomes.   Did the regular power on and then did the power on holding down a variety of keys.  
  • JackE
    JackE ACE Posts: 45,202 Trailblazer
    >>>At power on, keyboard back light flashes - nothing on screen.>>>

    Sorry. Back to the beginning. This now seems to me like a BIOS chip hardware or firmware failure. Otherwise known as a bricked machine.This usually but not always happens due to a failed BIOS firmware update. It can more rarely also mean a chip hardware failure. So I must ask if this seemed to happen suddenly without warning for no apparent reason? Jack E/NJ

    Jack E/NJ

  • northland
    northland Member Posts: 30

    Tinkerer


    The machine is my wife's.   She reported that it worked fine one day (and all days prior) ... then at next power on exhibited the symptoms I have reported here.   There certainly was no user initiated firmware update or anything of that nature.
  • JackE
    JackE ACE Posts: 45,202 Trailblazer
    Here's the troubleshooting flowchart. I think we've checked just about everything including the SW2 switch when you were in there checking the KB connectors. But let's take another look and maybe re-trace in case we're missing something. Jack E/NJ

    Jack E/NJ

  • JackE
    JackE ACE Posts: 45,202 Trailblazer
    PS: Let's check the power adapter open cirrcuit voltage output at its plug again if we haven't done so already. Should be about 19v DC. Jack E/NJ

    Jack E/NJ

  • northland
    northland Member Posts: 30

    Tinkerer


    Did not recall reference to checking SW2 before (perhaps I ought to have realized the need but did not).    In any case, as far as I can tell there is no SW2.    That is to say there is no switch evident to me at the designated location (though SW2 label is on the motherboard).   See the attached photo.

    Checked the power supply and voltage is as indicated.    In fact, where the target machine is my wife's, I have the identical unit and had tried my power supply before posting my initial inquiry.