my amp has a mm phono stage, would this be suitable?
Yes. There are basically two popular types of pickup cartridge fitted to Hi-Fi turntables, Moving Magnet and Moving Coil. The only difference between the two, from a practical point of view, is that the output of a MM cartridge is higher than the output of a MC one.
MM cartridges are typically cheaper than MC ones and are the only type available below about £100. For that reason budget amplifiers sometimes only came fitted with a MM input as it was reasoned that few people would want to use a very expensive cartridge through a budget amp.
All this means for you is that you need to use a MM cartridge. If you plugged a MC cartridge into your amp you'd hear the signal from the record but it would be very faint. It's not much of a limitation as there are many fine MM cartridges that will serve you well. As the deck is old it's probably wise to replace the cartridge as the stylus might be very worn and the cartridge suspension stiff. Have a look and see what kind of cartridge it is, it will have markings on it. You could ask your uncle how old the cartridge is, you might be lucky find it's perfectly usable. Doubt it though so swapping it for an Audio Technica AT95E would be a good idea.
Do I have to separate the inner and outer wires within the phono plug and is this a straight forward procedure?
If you've soldered stuff before then yes. If not you'd be better getting a mate to do it. The wires in the centre of the cable go to the pin on the phono plug and the outer wire goes to the body. When you open the back of the phono plug you'll see what I mean, it's obvious. Remember to SLIDE THE PLUG BACKS onto the cable BEFORE you solder the plugs on! Trust me, everyone who's put plugs on has forgotten to do it at least once and it's VERY annoying.
Is this turntable any good?
It's probably pretty decent. Rotel were very well known for their solid quality, good sounding budget kit, especially their amplifiers, so although their turntables never set the world alight they would not have been junk. In good working order it's probably on a par with a deck costing maybe £200 to £400 today. That's a guess but it'll be in the ball park.
The key phrase is 'good working order'. It's a mechanical device and is old meaning it could almost certainly benefit from some attention.
I would:
Clean out the bearing and put new oil in it.
Clean the drive surfaces and fit a new drive belt.
Replace the rubber mat with a felt one.
Check the play/float in the arm bearings and adjust if necessary.
If after that the deck is working correctly you're good :0)
