Tracy, the tweeter circuit runs through the bulb, nothing runs parallel with it. Did you actually check it for continuity? Steve said if it is indeed open, you can bypass it with a .68 to .75 ohm resistor. If you want to replace it, make sure that the bulb has a welded filament otherwise you will add distortion. The best solution may be to buy a used CX17 for parts. The bulb in that is rated at 1.0A instead of 1.4A. You would have the protection, but at a lower level. The 6.5" driver is the same used in the seven. The wire wound pot is to attenuate the tweeter level.
The design on the center channel is based off the CX17. The new cabinet is made from 1" black walnut that was stain black with Indian ink and finished with 7 coats of polyurethane, wet sanded and wheeled. From a few feet back it looks like a piano black finish, when you look close you can see the wood grain. The front and middle baffles are made from 1/4"lead laminated with 1/8" dense vinyl. The rear baffle is 1/2" thick, removable and made from just laminated vinyl. The cabinet has the same look as the CX17 with the chamfered edges but is longer and deeper. the internal volume was increased by 10% (Steve said that the original design for the CX17 was made 10% smaller for better use of stock materials). It still uses the 6.5" diver (the same as the Seven) but the tweeter was upgraded to the ones used in the Sevens. It is diamond coated and the magnet is larger. The crossover uses the same circuit board as the CX17, but two of them like in the Sevens. I saved the low pass inductor, the circuit breaker, the dampening circuit inductor (which had to be rewound), and the bulb. To upgrade to the Seven's level you have to change the values of the cap and inductor in the dampening circuit for the new tweeter, add the delay circuit (which includes four inductors, seven caps and one resistor), add a 5 ohm pot and a 10 ohm resistor in parallel to the one tweeter to compensate for dropping the other two out from the Sevens design. All the resistors are Mills. the caps are all Panasonic polypropylene except for one Axon for the high pass and one Blackgate in the dampening circuit. The inductors used in the Sevens used spools with powder iron cores all custom wound at DCM. The problem was that the four inductors used in the delay circuit need to be spaced properly because they interact. The inductors are not available so I had to cannibalize the inductors from four other CX17 I previously bought for parts, strip them, and rewind to the new values. I used the same layout on the boards then for the new crossover. The cabinet and grill are done. I'm waiting on some parts to finish the crossover. When I'm finished, Steve offered to come over test it against the Sevens and tweak it, if necessary. I'll try and take some pictures tonight and see if I can figure out to post them.