My motherboard came gradually to a complete death and I'm trying to figure out if one can repair it by fixing some capacitors like in the old days.

I went through all the arrays of caps as well as the single ones with my multimeter and all seem fine at the first sight (loaded up with the 'beeper' mode and then showing some voltage, gradually decreasing).

But there are these boxy things with two thoroughly soldered pins, that I can't figure out:

Dark gray boxy things

Q: What are these?

They are of perfect cubic shape with side of about 1 cm (about 2/5 of an inch). Written on them is R50, but they show no resistance. There are similar components at various places on the board, labelled 1R2 or 3R3, but none of them have any measurable resistance.

I'll appreciate any help! In case I should supply some more info, I'm ready here with my lousy multimeter...

  • \$\begingroup\$ what are the symptoms? \$\endgroup\$
    – iggy
    Commented Jan 3, 2015 at 18:24
  • \$\begingroup\$ The computer wouldn't make it even into POST, no beeps, nothing - fans spun, CPU phase LEDs glowed and that was it. Taking the whole thing apart to bits and replacing together did help, however, ant the computer works again now. \$\endgroup\$
    – Pavel
    Commented Jan 4, 2015 at 8:35

3 Answers 3


These are SMD inductors

  • The cubic parts marked R50 are 0.50 μH SMD inductors. The R is used to indicate a decimal point.

  • Internally, these inductors are coils of wire wrapped around a metal core, encased in a rigid block to suppress coil noise.

  • These inductors are used as part of the CPU voltage regulator, in tandem with the capacitors to the right of them in the photo and MOSFETs beneath the heatsinks (branded "DrMOS").

  • \$\begingroup\$ could they be part of a 4-phase synchronous buck converter to provide the 1.6-1.8V core voltage? \$\endgroup\$
    – KyranF
    Commented Jan 3, 2015 at 17:50

I would say those are inductors. If this is the case - the less resistance you measure, the better.


They are Ferrite chokes. it's related to voltage regulator module (VRM).


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