I bought broken sega megadrive 2 clone console. Something wrong with 7805 IC supply (I changed to another, but no result). But now I want test electrolitic capacitors and resistors, because I thing somewhere short/open circuit exits. I have chinese made capacitor meter. If I measure some capacitors with meter it show good capacity. But if measure some other so tester shows "1". But if i remove that capacitor tester shows correct capacity. So how realy test capacitors in board? I need to buy other equipment ? Or something else ?

Megadrive 2 circuit board:

enter image description here

My capacitor tester:

enter image description here

I'm trying to test 100 uf electrolitic capacitor with 200 uf setting set on tester.



1 Answer 1


It is not possible to test the capacitors while they are still soldered onto the board. Because the capacitors are connected to other things, the measurement will not be accurate. This is especially true of power decoupling capacitors, where the measured capacitance will actually be the sum of all the decoupling capacitors.

As an alternative I would suggest using a continuity device to check for shorts. Since your meter does not have that feature, you can use the ohm-meter to check that out. An excessively low number will indicate a capacitor short.

  • \$\begingroup\$ So use ohm-meter. Any ranges? I have another tester with beep signal. Does it suitable to detect shorts? \$\endgroup\$
    – kesrut
    Commented Jan 7, 2014 at 2:23
  • 1
    \$\begingroup\$ "tester with beep signal" = continuity device = suitable to detect shorts. \$\endgroup\$ Commented Jan 7, 2014 at 2:41

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