of the present invention and looking now at fig7 an external pcb 125 is electrically isolated from i e spaced away from but attached to heat sink 35 via a plurality of posts 130 e g four posts at each corner of the pcb heat sink assembly and four posts spread equally across the middle of the pcb heat sink assembly the height of posts 130 is set to match the back end of the optical module 5 such that the back end of the optical module which contains the pins 25 of each light source 10 will connect directly into external pcb 125 when the optical module 5 is mounted to heat sink 35 in some cases this connection may be made via an adapter in other configurations the analog part of external pcb 125 may be connected directly to the light source 10 of the optical module 5 and the digital electronics will reside on external pcb 125 it should be appreciated that the number height and or configuration of posts 130 can be varied so as to accommodate different sizes of heat sinks and pcbs in addition although one external pcb 125 is shown in fig7 a plurality of external pcbs 125 could also be provided e g arranged in a side by side configuration it will be appreciated that in addition to securely mounting optical.