This refers to the sinclairc5.com documentation, also available at C5Alive. I want to use a CB board to make up some test equipment for my Pedelec conversion. I took a damaged CB board and intended to repair it for this use. I found that the land from X12 was burned out, so I bridged the gap with a piece of wire. To ensure the repair was correct I referred to the CB circuit diagram (C5-UnofficialServiceManual, Page 24, Fig. 4), X12 is connected to pin 5 of X6. I conducted a continuity check only to find no reading, I redid the work and still had no reading.](*,) ](*,) I then traced the land from X12 and found it was connected to pin 6 on X8. According to the circuit diagram X8 pin 6 is connected to X13.[woot] [woot] At this point I decided to check the complete circuit diagram against the board, and this is what I found. On the circuit diagram X12 and X13 are transposed X6 pins 1 and 2 are transposed. These discrepancies have no effect on the CB's function, but messes you up when trying to trace faults. Further discrepancies can be found in: Page 25 'Reliability' 'Instrument pod' "Connect a 47 K resistor in series with the track from X1 pin 6 to IC1 pin 3." Page 27 'Known Problems with the C5' Article '4' "The robustness of the pod can be increased by fitting a resistor of value 10 K Ohms in the lead feeding pin 6." Why, when a 47 K resistor should be fitted, or is the 47 K an inaccurate value.
posted on: 30/12/2014 21:31:34