I recently picked up a Randall RT100 head, the person I bought it from gave me a stupid good price because he said he needed to preamp tubes. I dont really have any experience with tubes so I took his word for it, my only experience with tubes a Peavey ValveKing and its never given me an issue like this. So I take out the old tubes, it takes 5 but I only have 4 so I put what I have in hoping for at least some sound but not only does nothing come out but the preamp tubes dont even warm up while the power tubes do. My question to the tube gurus out there is if its normal for none of the preamp tubes to warm if the last one is missing?
I'm by no means a "tube guru", but I suspect that the design is such that it won't operate without all tubes working, to protect tubes, capacitors, etc., which could possibly be damaged by this. I would suggest that you don't turn it on until you have a full set of working tubes.
If you have a tube out, it likely won't operate, there is a chance though, that they could be getting power. Without looking at the wiring diagram, I have no real idea. These guys are local to me, but they do most of their business internationally. http://www.thetubestore.com/Tubes/12AX7-ECC83-Tube-Types They may be able to help you out, as far as tubes/amps they are outstanding. The other option would be to head to ultimate guitar, there are some very knowledgeable guys on there. Realistically though, you should replace the tubes with proper, no hours tubes. If you want it to sound at all good.
First thing - there wont be ANY sound unless you have all the tubes . I had this exact problem with my marshall(one of the ECC83s were blown out). What you need to do is buy a 5th tube! Go to http://www.ehx.com/browse/vacuum-tubes and order a fresh 12AX7.