Hi,

can you check the HV reading from teh front meter,
s/b 850-900v if half that electrolytic cap(s) need replacement.
digikey has modern caps that fit nice, info in the yahoo forum below.

you may not have a tube problem, could be something else,
as posted, more info is needed to help figure it out.

also, is screen grid switch turned on (black switch at rear of radio).
it is easy to slide it off if radio is moved and no output if it is off.

avoid the imported tubes, others have had instant tube failures using
made in china tubes and this also takes out cathode resistors.
rf parts and www.surplusales.com have us made tubes,
surplussales has tube specials along with the driver tube.

join other ts-5xx/8xx fans here,

http://groups.yahoo.com/group/TS-520_820_530_830/

lot of info in file section, messages are public access.
tube neutralization info in the public and file sections.

these radios don't like to sit unused, most of the time they need
a cleaning of the band switches and you are on the air again.

could be driver tube, always change it first (save the old driver
for use in another radio) before the finals.

73 james