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    issues recapping a dc7700 usdt

    Im recapping some hp dc7700's from ucc kzg series caps to some nichicons and panasonic caps. First board I did worked fine after. Second board went much faster but no video output on boot, and doesn't appear to boot completely (hard to tell since they do a long mem test after removing the cmos battery)

    I resoldered all the caps and have the same problem. I decided to test them with my multimeter to look for any differences / dry joint issues, and while 6/7 caps have the standard reaction for resitance check where it beeps for a second and then climbs out of range, 1 cap on the other hand has a steady 18 ohm resistance, should I assume that I soldered that cap wrong (might have solder touching another trace)? or consider that I might have destroyed the cap since it gave me a lot of trouble soldering it / and took like 5 seconds to solder it vs the .5 seconds on most of the other caps.
    Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

    #2
    Re: issues recapping a dc7700 usdt

    You can try taking it back out and checking the resistance between the pads again (and maybe the resistance of the cap too).

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      #3
      Re: issues recapping a dc7700 usdt

      I used some wick to remove some of the solder on that joint, and it no longer reads a steady resistance, now it charges / goes out of range for resistance. The motherboard still doesnt work though: still shows no video and doesnt appear to be booting completly. Ill probably swap out some of the other caps again / but this board isnt invulnerable so im worried ill only be able to solder / unsolder the caps 1 or 2 more times.
      Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

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        #4
        Re: issues recapping a dc7700 usdt

        Originally posted by cashkennedy View Post
        The motherboard still doesnt work though: still shows no video and doesnt appear to be booting completly.
        I find one of these useful for less than $2 USD + Free shipping. It gives a clue where to look, but not all the time.

        http://www.ebay.com/itm/310662804829
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          #5
          Re: issues recapping a dc7700 usdt

          Check the resistance of the same cap on a working board. If it's for the chipset, chances are it will (and in most cases should) read low resistance.

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            #6
            Re: issues recapping a dc7700 usdt

            Wow I didn't know those 2 number post displays were a like universal type of device / I have plenty of nicer motherboards with those (evga / abit).

            And thanks for the good idea Momaka, I will compare to some of the other dc7700's I have and report back.
            Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

            Comment


              #7
              Re: issues recapping a dc7700 usdt

              I have the same problem with my motherboard (HP DC7700 SFF)...
              The computer starts but I get no display and it will not boot..

              I have changed few of the capacitors (1000uF 6.3V) which looked bulged on the top, two had a small visible leak on the top.

              I still have the same problem, the motherboard will not boot and shows no action through the display

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