[Yaesu] Yo-901 monitorscope

[john]

Hello All,

I recently got a 901 monitorscope with the bandscope option, BUT it has no 
raster. I'm suspecting the voltage doubler since otherwise the thing looks 
good, no signs of meltdown etc. I can see filament on, but no trace on the 
scope itself.

Was there ever a service manual for these things, or am I on my own? Any 
generalized faults that I might look at first?
Thanks!
73
John k5MO