Question Laptop Charger Question..

Discussion in 'Desktop & Laptop Computers Forum' started by spideypunk, Jul 8, 2019.

  1. spideypunk

    spideypunk
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    Hi all! :)

    I have an HP laptop that when googled says it shipped with a 120w charger, during a move that charger been lost but I have a 65w Dell charger which fits and appears to power everything on..
    The HDD spins up and the CD drive laser makes the usual noises, fans spin, keyboard lights etc but the display does not come on. Not even a flash of bios screen or anything. The same result when I remove the HDD. Is this a product of using the lower wattage charger? Or should I not waste my money buying a new one? Thank you!!
     
  2. ChuckMountain

    ChuckMountain
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    It depends, using a lower spec charger usually gives an error message in Windows anyway.

    Depending on how much juice the laptop actually needs then it is likely the battery will not charge whilst the machine is running.

    However for quite a while, not sure if it is still the case dell and hp laptop chargers looked the same but weren't compatible.
     
  3. EndlessWaves

    EndlessWaves
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    Lower wattage just means it'll charge the battery more slowly and won't affect the laptop turning on (provided the battery is present and partially charged).

    It's voltage that is crucial, just because it fits doesn't mean it's the same voltage and if you connect a different voltage of charger then it could damage the laptop.
     
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  4. techquest

    techquest
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    Agree with @EndlessWaves.

    The voltage should be on the laptop base. You could be causing damage if it does not tie in with the correct charger.
     
  5. techquest

    techquest
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    What model is the Laptop?
     
  6. spideypunk

    spideypunk
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    Thanks for the reply, much appreciated.

    It is a HP Pavilion DV7. Putting it into YouTube the plot thickens, it’s possible the GPU has overheated causing black screen of death!
     
  7. John7

    John7
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    You cannot make a diagnosis like that until you use a power adapter that has the same voltage and power (Watts) output (IMHO). The one you are using has half the power of the original and will not supply enough current to drive CPU/GPU, unless you are confident that the laptop battery has good charge and can supply the requisite power.
     
  8. techquest

    techquest
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    Your PSU is 18.5V 3.5A 65W

    https://www.amazon.co.uk/Laptop-Cha...r&qid=1562683838&s=gateway&sr=8-1-spons&psc=1

    The Dell PSU could well be 19.5 v which I know they used to produce with a similar plug to that of the HP PSU's plug.

    So sadly you might well have blown the MB or CPU etc, hard to tell. You could check to see if there is any output to a monitor or tv by connecting either the VGA or HDMI outputs to a TV/Monitor. That way you could see if any signal at all is coming out of the laptop. But you would need the correct PSU to do so or you risk more damage using the wrong psu.

    As @John7 states you would probably not have the correct voltage to make it work.

    The correct 18.5V 3.5A 65W will be written on the base.

    The output of the Dell PSU will be written on the back of the PSU. What do the numbers say. Might need a magnifying glass to read.
     
    Last edited: Jul 9, 2019
  9. John7

    John7
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    It's highly unlikely that a PSU voltage which is one volt lower than design voltage would "blow" anything.

    It is very likely that using a PSU with half the current capability will be unlikely to provide sufficient power to drive hungry components such as CPU/GPU (if the on-board battery is depleted)!
     
  10. ChuckMountain

    ChuckMountain
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    Agree with John7, 1 volt would be well within tolerances for a power supply adaptor and/or laptop to handle.

    As stated before there was a compatibility issue based on the signal from the psu that meant an hp and dell were incompatible even if the same voltage and power output.
     
  11. spideypunk

    spideypunk
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    Thanks all, the plot thickens.

    Just for extra confusing variables, I am not using a battery at all as the one I currently possess did not function at all when the laptop was last used.

    I shall try HDMI out, I do not possess a VGA monitor (or cable).
     
  12. spideypunk

    spideypunk
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    Dell PSU first pic.
    Indeed labelled as 19.5v.

    Laptop under battery door second pic.
    It says 19v 4.74a or 18.5v 3.5a.
     

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  13. techquest

    techquest
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    Assuming, that is, the tolerance level of the PSU is not something like 19.5v +10%, that could possibly cause damage. In any event I think we all agree its best not to plug in an incorrect PSU.
     
  14. techquest

    techquest
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    The 18.5v mentioned is probably a 110v/127v 60Hz input derived value.
     
    Last edited: Jul 9, 2019
  15. spideypunk

    spideypunk
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    Good point. Shall I order the Amazon one for tomorrow and see? Seems like the logical step?
     
  16. techquest

    techquest
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    Sorry @spideypunk that's your call but if it helps here's a cheaper option:

    hp pavilion dv7 charger | eBay

    Can't even advise you to go for a non Chinese product as most PSU's seem to be from there these days.

    The bay is as good a place to buy as any, save with Amazon it's less problem sending it back, especially within 14 days, if for whatever reason you no longer need it.
     
  17. ChuckMountain

    ChuckMountain
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    Mains voltage in the UK can vary from 220 to 250v so there has to be quite a bit of tolerance. Voltage isn't as important as frequency from a mains distribution point of view, but I digress.

    Since you have no battery at all then the psu is the only thing supplying the power. Given it's so far off spec then is the most likely cause of not working.

    If you buy the one from Amazon and it doesn't work then return it, you won't lose out that way.

    You probably will be able to source a battery for it too.
     
  18. ChuckMountain

    ChuckMountain
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    That doesn't seem the right spec?
     
  19. spideypunk

    spideypunk
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    Thanks guys, pulled the trigger on the PSU so will report back tomorrow. This one from Amazon has my model in the title so I think I’m on the right track. I’ll try HMDI out for fun.
     
  20. ChuckMountain

    ChuckMountain
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    Which one did you go for?

    As the ones linked to do far have been 65w?
     
  21. spideypunk

    spideypunk
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  22. techquest

    techquest
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    There's a whole raft of them HP Pavilion DV7 Output Voltage: 18.5v ~ 3.5A, 65W

    They're the correct spec for sure.
     
  23. ChuckMountain

    ChuckMountain
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    Sorry apologies was looking at the original post where op stated the original shipped with 120w one
     
  24. spideypunk

    spideypunk
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    Sorry about that, I got that from a spec PDF that I found on the HP site when Googling, I just thought it was 120w or 90w from memory. I will try this one out and see what happens.
     
  25. ChuckMountain

    ChuckMountain
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  26. techquest

    techquest
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    Here's the spec from HP for clarification so we are all sure.

    Operating voltage 18.5 V dc @ 3.5 A - 65 W

    An 18.5 V dc @ 3.5 A - W90 version, if you can find one, would also be okay.
     
  27. ChuckMountain

    ChuckMountain
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    If it had discrete graphics then it would need the 90w one.

    The easiest way to tell would be to switch it on and have look at the display properties. Oh wait :facepalm:
     
  28. ChuckMountain

    ChuckMountain
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    What model number is it?
     
  29. techquest

    techquest
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    Agree the exact model number would tell us. It should be on the base of the lappy.
     
  30. spideypunk

    spideypunk
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    DV7-6c54ea from base of lappy

    It has 2 graphics cards as I remember, Intel and this one on the sticker.

    Cancelled Amazon order in time. :)
     

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