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.