The Beogram 1100 has an AC motor running directly from mains.
This means that the motors speed basically depends on the mains frequency which
is either 50 or 60Hz.
The dealer can change the voltage setting for the deck but NOT the frequency setting.
If you moved from a 50Hz area to a 60Hz area, your deck will run 20% too fast.
This can confuse a non-experienced tech guy into bodging about with the fine speed
adjustment or something else inside the deck to try and make up for the speed error.
I obviously cannot tell you what has been done in your deck but it could be something
like that.
It's not all tech guys who knows enough about turntables to do a proper service at all
and what he should have done is replace the motor with one suitable for 60Hz.
I doubt that this was actually done, I'm sure that he merely flipped the voltage setting
switch found inside the deck.
Maybe he fitted an un-original motor of some sort. I've seen many things in my time.
Supposing the above was done correctly, it could also be a mechanical fault to the speed
switching mechanics. The change from 33 to 45 is obtained by lifting an idler wheel up
or down to run on either a smaller or larger diameter part of the motor pulley.
The mechs here can go wrong, especially if the tech guy wasn't aware of it when he did
the conversion and/or if the deck was banged about in transport.
If what you mean by a very slow 45 RPM is actually 33 RPM, a faulty speed switching could be the reason.
Watch the idler wheel (with the rubber edge), check at 33 and 45 if it runs on the upper and lower part
of the motor pulley respectively.
The copper colored pulley with the round plate is the motor pulley.
You can watch this by simply lifting off the platter.
For reference:
An original (unmodified) Beogram 1100 should look like this under the platter and
from below:
Martin