Help need with CDM 0 laser

[tranguru]

Hi all,

I just bought a cd 204 with a CDM 0 transport (seems to be one of the first 204s). it is version IV (A sticker on the chassis)

behavior/measurement/fixes of the player:

• The disc does not turn
• after a few seconds I get "error" on the control panel
  
• laser head tries to focus (I think) - it moves up and down for a a few seconds when I close the drawer
  
• I can't see any light coming out of the laser - I assume I should a small red dot
• so far I have measured the power supply
  
• I have replaced the elec caps on transport's control PCB - no change

does anyone have any advice?
Should I be able to see the red dot? what measurements can I take on the CDM's PCB to see if the laser should be on?

Thanks
Robin