Well of course you have to make sure that the neckboard is firmly pressed onto the CRT. Gently try pushing it towards the screen on the center of the board !
What now? you ask.
Well since the solderings apparantly are OK, BUT you still have no 6.3 V (you did put it in AC right ?) follow the black and white wires to the main PCB and measure again there where they are connected to the main board.
If you DO have 6,3VAC there, there's something wrong with the wire(s):
Check the wires (pull each wire on each end, does it feel firm or loose ?, Check the solderings of the wires on both sides)
If you still do not have 6,3 VAC there, follow the traces on the main PCB to where it connects to the Flyback. Measure there again. If you still have no 6,3VAC on the Flyback, you can bet that it's dead. Still weird that you hear start-up crackle in that case though.