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Thread: Help to save a Dell Precision 220.

  1. #1

    Default Help to save a Dell Precision 220.

    Ive just been fixing another old machine that last year failed to power up. I had it powered up last probably 6 months before that. I guessed it was probaly the power supply which it was as it was the original. I stripped it but then never got back to it until now. I looked at the power supply and noticed I had removed a transitor but not put another one in. It was a KA431AZ shunt regulator. I replaced it with a new one and the power suppy fired up and it outputting all voltages. Then I connected it back up to the motherboard and it turned turned on but no boot up or screen display output. I could not see any reason why and decided that all the caps are ancient maybe one may have failed too I repalced them all. This made no differnce and it still turns on but apart from the motherboard led lighting up and the power light flashing yellow on/off it does not boot or output any picture. Stangly it wont power on with the cmos battery in either and if I put it in I cant get it to turn on until again until I remove the battery and then pull the mains power lead out, hold in the reset and power button together until the motherboard led's go out. Then as long as I leave the battery out it will turn on again from the power button.
    Be a shame to have to scrap it as its in A1 condition but its one of these partly SMD motherboards and I am not sure they are fixable anyway aprt from the larger electro caps.
    Can anyone advise can it be fixed? Here are some pictures.
    Attached Images Attached Images

  2. #2
    Join Date
    Oct 2017
    Location
    SE Michigan, USA
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    413

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    Could be a bad trace or solder joint somewhere on the motherboard itself. Also, remove one of the CPUs and see what happens. Also, this section is for the 386 and 486 class machines only and this looks like a Pentium III machine to my eyesight.
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  3. #3

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    Quote Originally Posted by retro-pc_user View Post
    Could be a bad trace or solder joint somewhere on the motherboard itself. Also, remove one of the CPUs and see what happens. Also, this section is for the 386 and 486 class machines only and this looks like a Pentium III machine to my eyesight.
    Thanks for the reply. Its shame this hapened and i thought it was just the psu. I didnt know a cpu could be removed and it would still boot up. Sorry I put this in the wrong section and if a mod reads this please move it to the right section.

  4. #4

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    Quote Originally Posted by roadrash View Post
    Thanks for the reply. Its shame this hapened and i thought it was just the psu. I didnt know a cpu could be removed and it would still boot up. Sorry I put this in the wrong section and if a mod reads this please move it to the right section.
    It does not boot up without a CPU. This is about checking the connections and looking out for broken contacts and so on...

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