HP 8150 51.1 and 40.2 errors - replaced everything

[DCO57]

Fellow techs
I'm working on an HP 8150 that freezes at bootup, then comes up with a 40.2 error first, then starts with a 51.1 (first time I've every seen two errors).
Both of these errors point to "beam detect" issues. I've replaced the scanner, DC Controller, and checked all cables.....no go.
This one has me stumped. I wanted to see if anyone has dealt with this before sending for another scanner and DC board (rarely do I get DOA parts, but it does happen).
Thanks
DCO57

[MichaelTech]

Check the top covers lower right area for the tang that acuates the scanner.
Check the acuator, may not be seated right.
Pull formatter and try a start.

[cs_steve]

If you remove the transfer roller ... check the connection points (not on the transfer roller but inside the printer ) ... if the copper connection points are dirty, missing, or bent/out of place, I've seen that cause similar errors ... very strange

[DCO57]

Thank you both, but still nothing.
BTW - I was mistaken about one of the errors - its 41.2 , the 57.5 - they both point to the scanner or related items. Also, I forgot to mention that in addition to replacing the scanner and DC Controller, I also replaced the LVPS.

Perhaps the HVPS?

Thanks again

DCO57

[MichaelTech]

Just a thought, when you put the top cover on, is the cable for the control panel getting pinched? How about the delivery assy. cable, and flags?
Check it's PCB on the left side for a bent sensor.

[cs_steve]

Ah, 41.2 is actually the exact error you'll get when the transfer roller contacts are damaged/dirty/missing ... I would check it again...
you can actually pull the copper "leaf spring" on the left side of the transfer roller, and try running some pages without that copper leaf spring installed ... my guess is the copper contact is bent ...
see if the 41.2 error goes away with that copper contact removed ...

if you have another 8100/8150 around to compare, pull the transfer roller out, and look in the transfer roller cavity, compare the copper contact and silver contacts with the working 8100/8150...
I really think that's where the problem lies...

- also you can try different toner cartridge ...
- replace HVPS ...