Fitting RTC battery

The hardware reference manual (XM_A2_01) is less than convincing about
the instructions to do this. Page 60 states that 'R66' must be removed
and Section 9.11 should be consulted. Section 9.9 on page 132 says
'remove R65 as shown on figure 73' but figure 73 is just a picture of
the battery. Figure 75 shows resistor R65 but does not show how to
remove resistor R66. It is not clear from Figure 66 (which is a
picture of an 'audio-in' plug) how to locate the positive lead of the

Should we rely on inspired guesswork or has someone competent written
some instructions that are correct please?

Remove R65 by heating up the resistor with a soldering iron. You can also heat it on one side and then just pry it up. Then unsolder the other side. Look at Figure 74 for the proper location of the positiver lead of the battery. In addition you can refer to version A3 of the System Reference Manual where these issues have been corrected.


Many thanks. Just didn't want to guess which bit was correct. I have a
revision B board, presume this is still the same instructions?

Revision A3 and B of the SRM are not available yet, only the BB C4 and
BB XM A2 manuals are currently available from the web site.

Yes. Rev B is the same as Rev A3 but with an newer revision of the processor.