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Adjusting the targus pa350 universal DC Power Supply

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  • Adjusting the targus pa350 universal DC Power Supply

    How do I adjust the output voltage on a targus pa350 universal dc power supply? I cut the end off to try to hard wire it to a barrel connector that my laptop will accept, but it now only puts out 16 volts. I need 9.5 volts. It seems to have 4 wires (one ground, one positive, and two other smaller wires I assume to be the selectors for the voltage). I think it may sense resistance on these smaller wires, but not sure. I don't know what makes it choose the voltage. How can I adjust the output voltage?
    Celeron 2.53 Ghz Processor
    512M ddr memory
    Mimo 7" USB Display
    XM Direct Tuner XM Direct USB interface box

    1999 Mustang GT Convertible Supercharged

  • #2
    found out how to adjust the voltage! Its very easy. Just stick a resistor b/w the grey wire and ground wire. I used a 10k and 5k to make 15k. This got me 10 volts. The greater the resistance, the greater the voltage setting. I'm going to get some lower impedence resistors to try and get a consistent 9.5 volts. I'm also going to get a better voltometer b/c mine is messed up and reads about 2 volts off.
    Celeron 2.53 Ghz Processor
    512M ddr memory
    Mimo 7" USB Display
    XM Direct Tuner XM Direct USB interface box

    1999 Mustang GT Convertible Supercharged


    • #3
      Targus PA350 Voltage Adjust

      Hi I found this thread when I was looking for information on how to set the output voltage on my recently acquired (for free) PA350. I found some other information on the web and did some testing and came up with the following. This includes data from my own testing and a few posts I've copied from elsewhere to consolidate the information here.

      I hope this is useful to somebody.

      Setting the output voltage of a Targus PA350:
      The following data comes from testing of my PA350.
      The back of my unit is labeled with: 
          "PA350(Ver. 2.0) E0801"
      Looking at the plug on the end of the cord:
      |               \
      | 1   2   3   4  |
      | ?   +   -  Set |
      |               /
      1 - Red    - Unknown purpose
        - Maybe current limit. Connected internally to something.
          Setting resistors to pin 2 or 3 has no effect on output voltage.
          On my one tip (#24) this is not connected.
      2 - Yellow - Output Positive
      3 - Shield - Output Negative
      4 - Grey   - Voltage Set - See resistor table below.
      The output voltage can be set by placing a single resistor between the 
      Grey wire (pin 4) and either the negative or positive output wires as
      shown below. I got this data by testing my unit with an assortment
      of resistors (most were 5%, but some were 1%).
      Output    Grey to   Grey to 
      Voltage   Negative  Positive
       2.8        2.2K *
       3.3        2.7K
       5.1        4.75K
       8.0       10K
       9.7       15K
      11.7       27K
      12.3       33K
      13.3       47K
      13.7       56K
      14.0       68K 
      14.3       82K
      14.7      100K
      14.9      120K
      15.1      150K
      15.4      220K
      15.7      330K
      15.8      560K
      16.0        1.0M
      16.1        3.3M
      16.1      open       open
      16.2                   3.3M
      16.5                   1.0M
      16.8                 560K
      17.3                 330K
      17.9                 220K
      18.9                 150K
      19.6                 122K  (Resistor in #24 tip)
      19.7                 120K
      20.7                 100K
      22.0                  82K
      23.8                  68K
      26.4                  56K **
      * - The output went to 2.8V, and it seems to work, but the pilot light
          went out with this resistor. This is less than the unit's 3.0V minumum
          rated output voltage.
      **- With a resistor less than 68K from grey to positive the unit would
          shut down and set its output voltage to about 2.0V. It is necessary
          to remove the input power to get it to reset. With a 56K it would
          shut down when the resistor was applied, but would work when the 
          power was re-applied. I did not try it under load with this resistor
          so I do not know what would happen in that case. This is beyond its rated
          output of 24V.
      ================================================== =========
      Targus Power Tips voltage by Tip Number
      - From a posting at by Barry Watzman

      1 - +16.00 volts
      3 - +18.00 volts
      4 - +12.00 volts
      6 - +15.00 volts
      7 - +16.50 volts
      8 - + 8.40 volts
      5 - -12.00 volts (tip negative)
      10 - + 2.95 volts
      11 - + 6.00 volts
      12 - +10.00 volts
      15 - -10.60 volts (tip negative)
      16 - + 5.50 volts (wide variation)
      17 - + 8.50 volts
      18 - + 9.40 volts (wide variation)
      19 - +16.60 volts
      20 - +13.00 volts
      21 - +19.00 volts
      24 - +19.55 volts
      25 - +18.25 volts
      26 - +19.50 volts
      27 - +15.00 volts
      28 - +22.00 volts
      34 - + 7.00 volts
      36 - +18.26 volts
      38 - +24.00 volts
      44 - +18.90 volts
      47 - +13.00 volts
      48 - +18.20 volts
      57 - + 4.10 volts (wide variation)
      58 - +20.00 volts
      74 - +16.00 volts (wide variation)

      ================================================== ========
      Posting from somewhere else (I didn't record the specifics):

      Tip #24 [with one caveat, see below] will power the Toshiba Satellite
      A105 (nominally the A105-S2712 takes 19 volts at up to 3.42 amps).

      This also suggests that tip #24 will work with the A80, A85, L10, L15,
      L20, L25, M30X, M35X, M40-S312TD, M45-S165 , M45-S165X, M55-S139,
      M55-S139X, Tecra L2 and Tecra M2, since they all use the same Toshiba AC
      power supply (PA3467U). [and it is therefore very likely that it will
      work with additional models that use a different power supply but the
      same voltage]

      The measured voltage under an admittedly low dummy load (a 100 ohm
      10-watt resistor) was 19.2 to 19.3 volts, 1% to 2% high and well within
      any reasonable tolerance. The voltage would probably drop a tad under
      the much larger full load of the laptop, but a 100 ohm load will draw
      200ma, which should be enough to bring the power supply into proper full
      regulation mode. [And if anyone is wondering, yes, after my testing I
      actually did run the laptop itself from the #24 tip with no problems,
      but I cannot easily measure the voltage while the laptop is running.]

      ================================================== ========
      Posting from somewhere else (I didn't record the specifics):

      I set the output voltage (which is adjustable from 3- 24V) with a 27k
      resistor across the sense wires. (This is between the grey and the ground to
      get 12.1 volts) When I cut off the end there are 4 wires in the cable.
      A thick yellow one, a thin red one, a thin grey one and a ground (shield).


      • #4
        I know this is only but I had to thank miwise, great post! So wanted to know how they did this as they told be I could not order my tip for my unlisted laptop. Now I can make one!!

        I should have guess that what te 2 extra wires were for..
        UMPC built in to dash.

        Winamp, game emulators, Touchpad built in to car, DVD player built in to dash, GPS gamrmin moble pc. IR remote for use of a remote control. ps2 supper mini keyboard for when needed.