Len44: Hi. Even sceptics tell me that digital circuits can benefit from: (a) fresh electrolytic caps if the unit is an older machine, (b) electrolytic caps of same or better performance capabilities than the originals.
Are you good with an iron? Maybe you are an old hand. If not, get some breadboard and a pile of cheap caps, like from outdated job lots or something. There are some excellent tutorials on the net. Follow one or two and practise. You will want the best applied joints that you can perform efficiently without stressing nearby chips. If you see any polystyrene caps (usually little, clear plastic cylinders) be very careful of heat on any foil trace leading to them. Try to put a heat clamp on the solder miniscus of each leg. Perhaps I am eccentric, but I try to stick on a wad of tissue wetted with water on the foil side in locations of interest - say ... a vulnerable chip. If you hear hissing downstream, it's a signal that you are passing heat into the components there. Flame me ... whoever ... it works for me so far. Clamps, wet tissue, clean well-formed perfectly conductive joints.
As for choice of caps: Stay clear of NOS. Electrolytics have a shelf life, and this application wants fresh material. Personally, I can't afford Black Gates. Other choices are Nichicon's various flavors of their Muse series, Sanyo OS-Con in the DAC section maybe. Panasonic's premium audio caps are excellent value. Some of my players were built with Muse in strategic places.
An obvious place to start is the power supply section. Downstream circuits will benefit. Digital players depend on the best supply that can be acheived. If you can identify and isolate the servo section, it may not be an immediate candidate for new caps. Everything else is screaming for attention in the same order of magnitude - just my two cents of HO.
As for the tilting issue, I am out my depth here. Many of us would be because it may involve the tracking ability and set up in the laser and related parts in the transport. If there is a Yamaha service center near you, I'd stuff it in there to see what's up. If you are inducing error in the transport, I see no point in recapping and so on. A good technician can get it right *IF* he/she has the service manual with the specs. If you are a serious dude, you might try to track the manual down yerself and present it along with the machine. A Yamaha facility should have access to it. Yamaha has a vast data base and archives that can be accesssed by authorized persons. I got this from the horse's mouth here in Sendai. (I also failed to obtain a manual for a fellow AKer because I am not (duh) authorized for access.)
Op-amp rolling is sorda-kinda an alchemical art. What may be touted as an improvement may turn out to make little or no difference. Or, conversly, it make make a difference perhaps in terms of a trade-off. This is where personal taste comes in. On the other hand, we should also keep in mind that newer op-amps may have the benefit of improving technology AND manufacturing techniques. There is lots of stuff on AK and elsewhere to read and have fun with in this regard. If you wanna get into it, you can solder in beds of pin-out modules that allow you to change out and test multiitudes of op-amps by simply using a chip puller instead of soldering and desoldering each time you want to try out your latest choice. It is fun to think that a chip costing a couple of bucks may yeild improvement over the original that cost only 79 cents. But let us not forget that the engineers chose the original for a reason, and it is best that you try to know what that reason was. Back in the day, it was sometimes because it was just available. The range has grown substanially. For example, chips that are audio-specific are more abundant than years ago. Again, speaking personally, in my hobbby there is usually something more urgent to do than rolling op-amps. But ,some people revel in this stuff , and it must be just as much fun as tube rolling is for our members in vacuum-land. And cheaper too, except that here in Japan some imported chips are astonishingly expensive.
I'd begin by finding out about the tilting thing and then carry on from there.
Best of luck - Lorne