Welcome to the Great Vinyl Debate. As a keen owner of a Linn Sondek LP12 I can say that you're in for a real treat when it's all up and working. That's a fine piece of vintage audio you have there.
Regarding your Garrard:
Originally posted by hks_kansei That's the odd thing, the rubber felt soft and pliable to me.
Still hard enough to hold it's shape without deforming, but still soft enough that it has a bit of grip if I run my finger on it.
Pliable isn't necessary the best,. The rubber has to grip both the turntable and the motor and not slip. Also check the underside of the turntable and the motor spindle. Both will likely need cleaning (don't use sandpaper or similar - use a pencil eraser) In the UK when I worked for the BBC, we were taught to use Swarfega (a grease remover) to clean the rubber surface of pinch rollers of our Studer A80 tape recorders so that the smoothness of the roller was removed without changing its circumference. If you can get the idler wheel off you could try this and see if it improves things. Get rid of the swarfega with plain water - no soap - and dry it thoroughly.
Also - for setting up the stylus on the cartridge, try resting the stylus on a mirror placed on the turntable mat. A good excuse to try your hand at macro photography - get that stylus in close focus and make sure it's straight and true (the stylus and reflection are parallel with each other when viewed from the front) and that the weight is set correctly. Too much weight and the cantilever will gouge you a new groove in your record. Too little and it'll skate across the surface.
If you have a problem hearing any records you play then you obviously need to establish why. Here you are a bit helpless without the circuit diagram - or at least a list of the valves in the set. Be warned that valves (or Tubes in the USA) run high voltages that are dangerous, so a healthy regard for safety is the first tip I can offer.
Most valves have a number printed on the glass envelope and you need a list of these to help build up the circuit in order to know where / how to look for the faults. Again, some pictures of the markings on the valves may help others on the forum help you, so some more pictures please...
If you have the circuit diagram this would help - quite often this would be stuck on the inside of the set as a guide to the radiogram repairers of old, so look round at the set.
Hope this helps you get started on your road... Good luck!
Savcom