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inspiron 8500 DC power and CPU speed


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inspiron 8500 DC power and CPU speed

  • My i8500 power adapter just went bad and I've ordered a replacement.  It works, but the i8500 doesn't recognize it as a valid AC adapter. 

    My main question (1) is: is there a way to use the inspiron 8500 at full CPU speed when not using the Dell PA-10 AC power adapter?  I've been planning on using the laptop in a remote location off a bank of car batteries.  I'd like to use a DC adapter to power the laptop, but I’ve noticed, since the AC adapter isn’t recognized it runs the CPU at half speed.  Setting Speedstep to run at full speed for both AC and Battery doesn’t make a difference.

    Both the 65W Dell AC/DC adapter (Manufacturer Part# F2663 / Dell Part #: 310-4804) and the 70W Targus air/DC adapter (Manufacturer Part# PA358U / Dell Part #: A0098237) are lower wattage sources.  Neither will recharge the batteries in the 8500 so I assume neither will run the 8500 at full CPU speed.

    The option is to run the replacement PA-10 AC adapter from an inverter.  Since the AC adapter is an inductive load it may be damaged by non-pure sinusoidal inverters.  This would mean that I’d have to go with a very expensive pure-sine inverter if I don’t want to risk burning out the new AC adapter.

    Other Questions: (2) Is there a DC adapter that provides 90W?  (3) If so would the i8500 recognize it as an approved power source?  (4) Is there a way to fool Speedstep into running the CPU at full speed?  (5) Am I missing something obvious?

    -Joe Bauer


  • Ideally a DC/DC adapter such as
    Pure sine wave inverter is feasable but the added efficiency loss will be subtantial and unnecessary. Most 3rd party adapters do not offer the communications capability (handshake) needed for the 8500 - ie. the Targus does not, so regardless of the power, it will not charge.
  • I'd still like to know what options would allow full CPU speed. That's my main concern, charging batteries doesn't matter to me.

    That's an adapter I've never seen before. It looks like the closest thing to do what I want. I imagine it would run the CPU at full speed but I'd like to make sure. None of the other i8500 adapters say that they will run the laptop at 50% speed. I'd think that would be a major specification to mention in the product descriptions.

  • This will act like a 90 watt AC adapter. If your current AC adapter is 90 watts and the 8500 runs a full speed, then this DC adapter will as well. If not, you have a different issue unrelated to power.
  • Please can you provide more details about the handshake.
    I have a good AC adaptor but a bad connector at the laptop.
    Tried to replace connector, tried to use a dock station with no good results.
  • Not much to tell - 3 connections +, ground and signal Would recommend a new adapter as a start - hopefully comm chip in laptop is OK
  • Already tried 2 AC Adapter and a Expansion Station.
    Can you tell me any detail of how the signal communications works ?
  • A chip on motherboard with code interogates a chip in the AC adapter - if proper code is received - laptop says OK to work/charge - if not, charge function is disabled. My guess is - based on your experiences - a problem with mainboard - not good. I would recommend having Dell repair facility look into it.