Rick, You may not need an original type blower in that BTA, and the failure of the one you've got is a chance to cut noise in the room where the transmitter will be located.
Since you'll be running voice rather than higher duty cycle music programming, and since transmissions will be intermittent rather than continuous, I'll bet you can operate well within temperature margins on those 4-400s by configuring just about any lower flow blower you have laying around. Despite the original likelihood all 4 tubes would be operating under enough load to have their plates glowing in a broadcast application, RCA didn't even put chimneys on those 4-400s, probably concluding it was adequate to rely only on that blower to move lots of air through the cabinet. Your operating circumstances are far milder. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com