Quote Originally Posted by foto-r3
The fuse we are using (I think) is a normal blow --neither fast nor slow--. I don't know whether slow/fast blow is something you can see on the fuse itself, since I can look to see what the original was. Unfortunately, nowhere on the unit itself is there any indication of what fuse rating to use. Would there be some advantage in using one or the other in this case?

Maybe the thing to do would be to use it and see how long we go before another blow. If it occurs at long intervals maybe we can live with this, too. Fuses are cheap.
Firstly you should stick with the voltage stabiliser and not worry about a variac as I suggested, the voltage stabiliser will do what you are after given it is rated down to 187V, even if the input falls to 184V then this will not make a significant difference to the output for B&W work.

There are generally two types of fuses fast or slow (there is no 'normal' , but because fast blow are more common they could be considered 'normal' !). Don't assume that the fuse which came with the unit is correctly rated. As Michael suggests, get a copy of the manual, by going to the link he found and requesting it. That will tell you straight away the correct rating and type of fuse you need.
A fast blow fuse has a straight filament of wire in it, whereas a slow blow fuse will have the wire coiled at some or all of its length http://www.microfuse.co.kr/4fuse%20g...%20guide06.htm (this site names the fuses normal, medium slow-blow and time-lag. Normal is 'fast blow' and the 2nd two are slow blow)
here's a close up piccy of a slow blow fuse http://www.marcucci.it/prodotti/imm_comp/3004646.JPG
If the fuse case is glass then you will be able to see this for yourself.