On the Rowe R83 I have, all the 14 volt #73 bulbs are wired independantly.
If one is out, the remainder continue to function. I don't think Rowe
would put all the bulbs in series. If one bulb went bad, and they all go
out, it would be a service nitemare to find the bad bulb. The fact that
you say several bulbs are bad indicates that they functioned
independantly, and went bad over a period of time. (unless a power surge
made them all blow at one time).
PS: you can buy these bulbs from www.cdadapter.com