In the video, Let's figure out how to mod the BBC Master, at 30:35, a polyester capacitor is added to a BBC Micro to provide a colour composite signal (center of photo solder to the legs of two resistors):

Photo of BBC board

From the schematic, this capacitor (C28) should be 470 pF


However, zooming in to the capacitor on the board, shows a 4 digit code:

Capacitor close up

The markings are:


This 1135 seems to make little sense and doesn't correspond to any capacitor code that I know of, as these are normally 2 digits or 3 digits (plus a letter). Yes, there is a 4 digit EIA code, but that is for SMD capacitors

I am starting to suspect that the 1135 is a product code and that the actual value is printed on the other side, however, I don't have any polyester capacitors to hand to check whether they are printed upon both sides. Can anyone either confirm this suspicion, or determine the capacitor value from the 1135?

  • 2
    \$\begingroup\$ I would guess that its a date code, the 35th week of 2011, but someone more knowledgable will probably be along soon \$\endgroup\$
    – BeB00
    Jul 1 at 7:29
  • \$\begingroup\$ Ah, I suppose that would make sense, so presumably the value is on the other side. I had always thought that the printing was just on one side only. \$\endgroup\$ Jul 1 at 9:32

1 Answer 1


1135 is the date code. The part is a AVX (now Kyocera/AVX) CKR04 or CKR05.

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With the "Military Dash Number" from the other side of the part and the table in the datasheet, you can identify the capacity and voltage rating. For example, 1323 would be a CKR05BX120KS with 10 pF and 200V.

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