I recently picked up a NOS Fontainbleau Man 100 in Havana Brown from a shop in Kralingen while visiting. The pen is a wonderful writer when dipped, but I discovered on my return to the states the there is a problem with the feed taking ink from the converter to the nib. Specifically, it doesn't do so unless forced. The pen will draw ink from a bottle, so the feed is not totally blocked. But the pen won't write unless I force ink into it by twisting the converter. Then, once the ink from the twist is used up, the pen stops writing again. I tried repeatedly flushing the feed with a syringe and water doe travel through the feed, so it is not totally blocked. I also soaked the feed overnight in a water/detergent mixture. Today it is soaking in a water/ammonia mixture. What can I do to fix this? Please help!