Sharp JX9660 laser printer odd fault (dead, sort of)

I've just reassembled my JX9660 after tearing it down to clean all the
rollers in an attempt to fix a recurrent paper jam. On powering it up, the
lights flash briefly but the display stays blank, the transport motor starts
and the polygon runs up; after a few seconds the polygon stops and just the
fan remains on cycling 1 minute on and 5 minutes off (as if it's in power
save mode). I have been able to run the diagnostics mode, check the
switches, the high voltage section and run a test print although it still
jams frequently but it still won't power up normally. I reset the NVRAM and
then reset all the counters to the previous values in case there was a
problem with corrupt NVRAM but it's still the same. The manual doesn't list
this particular condition in the fault syptoms and I'm stumped.
Any ideas or suggestions?
Martin
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martin<dot here>whybrow<at here>ntlworld<dot here>com


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