Sorry for the delay.
You can find most service manuals with a simple google search 'there not top secret', but here are a few;
This one is dedicated to Lexmark and HP.
1) http://www.marketpoint.com/market-point-home.aspx
2) http://www.altra.de/manuals/Lexmark%20E23X-E33X-4505.pdf
3) http://www.eserviceinfo.com/
If i recall correctly, i believe #3 is where i got the PDFs listed, that your asking about.
All above are very useful site, #3 just type any manufacturer and model #. Very Very good site.
Darren.