IBM CGA Card  -  Capacitor C8


On the IBM CGA card, capacitor C8 is a tantalum type of capacitor, of the value: 10µF, 16V

On my IBM CGA card, it is a three-legged capacitor, where the outer legs are negative.  Photo at here.

Some very early versions of the IBM CGA card also have three holes for C8, but the three holes are wired differently; wired for a two-legged capacitor where the legs go into the outer holes.  Like here.

C8 (and C9) filters the +12 volts supplied to Berg connectors P1 and P2.  If you have nothing connected to P1 and P2, then C8 is not required.  Note that in the IBM 5155, P1 is used (per here), but the +12 volt pin is not utilised, only the video.  Therefore, if you have nothing connected to P1 and P2, or if your IBM CGA card is in an IBM 5155, then consider clipping the faulty C8 off the card, and not replacing it with new.


Replacement

Should you choose to replace C8:

•	For the cards wired for the three-legged version of C8, some replacement details are at here.  Those details include the optional use of a two-legged capacitor in place of the three-legged one.
•	For the cards wired for the two-legged version of C8, a replacement two-legged tantalum capacitor should be easy to locate.
•	Note that for the application that C8 is being used for, you may substitute an aluminium electrolytic type of capacitor, but ensure that it is low profile, so that the top of the capacitor does not touch an adjacent expansion card.