CBM 3032 (PET 2001N-32), no video?

Hello everybody! Just acquired a beautiful CBM 3032 (PET 2001N-32) today, and
I'm already running into problems... Which was kind of expected, given its
age!
I managed to get a first successful boot of the machine with crisp video.
BASIC initialised correctly and I was able to execute the classic "PRINT
'Hello world'" command with no problem. 
I then powered off the machine as I had to go away for a while. When I came
back, I tried to turn it on but to no avail. I hear a slight humming noise
from the power supply and sometimes, but not always, there seems to be a
sound right after flipping the power switch that reminds me of degaussing,
but I'm unsure if that's really what's going on.
I don't hear any other noise, including the usual pitched noise that comes
from CRT monitors when they're working. I also didn't hear any obvious
"failing noise", like crackling or pops, and I didn't see any smoke coming
from the machine. The fuse is fine. I can see the electron gun of the CRT
from the back of the case, but it's staying off - while on the first
successful power on I could see it glowing in orange. 
There doesn't seem to be any obviously burnt component on the main board,
and I've also already reseated the ROMs. I checked the +5V voltage on the
user port and it's correct. I also checked the voltage on the main power
connector (J8?) and it shows -9 V, which as far as I understood should be
the correct value. The +12V rail also seems fine. 
The symptoms seems a little suspicious to me, in that - if I'm not mistaken
- if there was a problem with the ROMs or the CPU, I should at least get a
garbage screen of some sort, which I'm absolutely not getting. There just
doesn't seem to be any sign of life from the CRT. 
So my question is - where should I begin troubleshooting? I don't have an
oscilloscope, but I do have a multimeter and some basic soldering
experience. I'm not too comfortable with going around the high voltage CRT
video circuitry, but I know a person that may be able to perform
troubleshooting on that part.
Thanks!



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