I recently purchased on eBay a Ilford Multigrade 500 system. The 500H Light source came from another source. The 500 S power supply, console unit, and foot pedal came from another person. Both parties agreed that the light source should match up with the power source. Much to my chagrin today I discovered they do not. The light source has 8 pins. 4 horizontal and 4 vertical. The power supply has 8 slots 4 looked to be horizontal and the other 4 slots look to be vertical EXCEPT the one in the upper left corner is round. What is going on here? Is the light source a different version? When I looked on the manual at Ilford's web site nothing was mentioned about a difference in plugs. Should I scrap this idea and send them both back? or should I keep one and send the other back? In the future what should I look for in trying to get the right match? thanks