Bose 108787 receiver
May I suggest that you get a 'service manual with schematics' for your specific Bose model receiver. Always get one to have just in case you need to reference to it. Plus it should give you information on specifics as far as what type of bulbs it uses, voltage and amperage ratings, etc. You would need to know exactly what type of bulb you need before looking for a replacement. If you're not into peforming the task yourself then I would suggest to contact Bose Corp. themselves and inquire about having it done, if so at what cost, turn around time, etc.
If you are going to do it yourself (be sure to "unplug the receiver" first before anything else is done to it) carefully remove the panels, sheild, cover, etc. and see if you can track the actual bulbs down and see what type they are, voltage, amperage, screw type, bayonet plug type, solder type, etc. and take it from there. The cost should not be much. Bulbs are not expensive and you would definetly be saving your self some $$$$ from cost of shipping and or labor (that is if it gets sent out to someone to have it done).
Good Luck!