PS: How can I test the FD to see if it still go? Develop a bw film with it?
FD will develop b&w film but you need to find out reference dev times before you judge the FD you have. AFAIK there are no published dev times for E6 FD and b&w films. You also need to account for the fact that E6 FD contains a strong silver solvent (most likely 1-2 g/l Thiocyanate) which means if you develop normally exposed b&w film you will lose shadow detail.
Note that E6 FD is not just some random b&w dev, it is carefully balanced to develop all three color layers at a predetermined speed. Use some hack instead and your colors will be off. There are formulas for E6 chemistry on APUG if you want to experiment. stefan4u also posted some interesting data.
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