Yeah, be careful here. It could end up like one of those classic car restorations where someone buys a car for £2k and then spends £10k restoring it when it's only worth £5k in mint condition
The Technics receiver is is nice from a novelty point of view. The old skool knobs and switches have a nice weighty feel to them which is quite seductive compared to modern electronics. It should also produce a nice warm sound. However, this is a bit of mid-Fi and there's plenty of other similar products on Ebay from equivalent and superior brands for around the £30-£80 mark.
If I was to do anything with the 303 it would be just to get the volume crackle fixed. My first attempt would be with some
Deoxit and a little elbow grease. There are different versions of Deoxit. For this kind of work where you want to preserve the delicate carbon track of the volume pot then you want to avoid anything with a solvent. Deoxit D100 is solvent-free. That's the right product to use. Basic contact cleaner and other versions of Deoxit contain some percentage of solvents. You want to avoid those for this type of job. If that doesn't work then by all means put it in the hands of a repairer.
Before you do take it off to a professional for a service just check if everything else works. Try the amp at progressively higher volumes. If there's a problem with the big output capacitors because they've dried out then I'd expect to hear it as they're worked harder at higher volumes. Crackly switches will just be oxidation again. Issues with tuning will most likey be another Deoxit job on the tuning fins (Google it).
As for the rest of the gear: The CD player was close to top-of-the-line back in the early 90's. But once again technology has moved on and something like a Denon 2800 DVD/CD/SACD/DVD-Audio (early noughties) would have it beaten for build quality, flexibility, sound quality and not to mention being a DVD player too, all for under £80 s/h.
The turntable is nice. Direct Drive with a reasonably weighty platter which helps smooth out motor noise. The arm is a bit on the heavy side so cartridge choice needs careful selection. If the cartridge itself is more than a few years old then there's a fair chance that the rubber suspension will be past its best. The suspension allows the needle tip to track the groove. As the rubber ages it gets hard and brittle. The cartridge will still make a noise but the distortion will go up and the diamond will start to plough a new path. This isn't good for the health of one's records
The speakers are a bit of an unknown quantity. Like most Japanese mid-Fi brands, Pioneer made some great electronics but their speakers never set the UK market on fire. The Pioneers will produce a big, in-your-face sound alright. However, this country produces some of the finest loudspeakers in the world, so it's a tough nut to crack for Johnny Foreigner
