IntroductionThis is a rough guide to adding an Econet interface to a BBC B+ machine. I will update this as information arrives, but having never seen a B+...
Please note that the model B+ is not the widely-manufactured model B. If you are looking for information on upgrading a model B, please look here.
This information is given in good faith. Liability for damages is hereby disclaimed.
What you'll needTo upgrade a BBC model B+, you will need:
Various 2% tolerance ¼W resistors, and capacitors as follows: To the immediate left of the Econet socket, reading downwards: 100K -- -- 10K 10K -- -- -- 100K 0.01µF ceramic cap. 1M5 1K Below the Econet socket, to the left of the IC92: 1M5 1K 100K 10K 10K 100K 1K5 Below IC91: 47µF tantalum capacitor, +ve to left 10µF tantalum, +ve is upwards Below IC70: 4K7 Below IC88: 39K Between IC70 and IC88: 1K To the right of IC88: 2.2micro;F ceramic capacitor Between IC91 and IC70: Link S29 should be made To the left of IC81 (between it and 10µF cap): 220K (stands on end) By IC80: 2 x 8 pin MOLEX strip 8 x 22K resistor pack 5 pin DIN socket for SK7 IC91 - 75159 IC70 - 74LS132 IC88 - 74LS123 IC92 - LM319 IC81 - 68B54 IC80 - 74LS240 or 74LS244 Also you'll need a DNFS EPROM. These ICs should be socketed.
DiagramI found a diagram on a BBC documentation website. I'll provide a link when I know it, until then, Google for "bbc service manual" (that's what I did).
This is not the original diagram. I've blanked out the 'deleted' components, and tightened things up for the webpage.