How repairable are Selectavision and other CED players
 

Recently I've come across some pretty big collections of selectivision discs and players on Marketplace for at least reasonable to me prices. I'm just curious most of the players have issues are they like impossible to fix or do they use simple and obtainable parts? I thought it would be cool to have one sitting on top of my CTC 16

If you can find one with a good stylus then you're in luck. Most everything else is common sense mechanicals and I do remember those RCA SFT-100 players were well built but never really got into them as we had the Pioneer VP-1000 laserdisc on our Magnavox.
Whatever you get I'd hunt down a service manual for it after confirming the stylus was good and don't pay too much.
Always liked the opening of Promenade by Isao Tomita on them. FYI that came from his Mussorgsky Pictures At An Exhibition album.

Thank you, I'm assuming they operate like a record player? I came across one that has to be loaded multiple times to play and another that they said you move a piece out of the way amd it will play fine. The latter one was $120 and came with 40 or so movies.

Most common problem on them are failed rubber belts... They work like a linear tracking turntable the stylus carriage advances with a rubber belt driving a gear train.
The early models with the big mechanical loading lever have fewer belts and less to go wrong but are fully manual load. The later models with push button loading are more complex but offer stereo sound in most models, and have the cool feature of pulling the caddy in then ejecting the empty caddy most of the way automatically.
Some of the later models have IR remote control and some can play interactive discs.
Another nice feature of the later players is using visual search to fix skips... You can't really clean the discs so if one skips you replay the part a few times until the dirt dislodges and flies off... I've had discs so bad you couldn't follow the dialogue go to like new in a couple of plays with a lot of back tracking on every Skip.

Thanks Tom, do you know of any that should be avoided? Also couldn't you get a dirty title to load into a player, then manually remove it by disassembly or some thing, then use one of those ultra sonic record cleaners to clean the record?

I haven't seen any consistently dog mechanisms. Some of the lever loads develop electronic issues (they're common enough mechs that I typically wait for a good cheap working one to pop up and sell the bad one dirt cheap as parts). The only one I remember being bad was one of the first stereo players...that was basically the lever load mech with the lever motorized, and a gear cracked...might have been a freak occurrence though.

You are not supposed to wash discs! They have a special, necessary silicone lubricant that can't really be replaced (the discs and styli wear out faster without it), also the grooves are so small that residue from cleaning agents or minerals in the water can cause skips.
Most washing of discs I hear of are discs that have been in a flood, have mud inside and the owner wants to play them once to record a copy before the disc dies.

I'm guilty of washing a CED disc long ago... didn't turn out so well.

Supposedly with the SFT-100's if you loaded a disc like the earliest commercials (shoving it into the unit with a little but too much effort that it really needs) it can damage the receiver in the player.

With the later auto-loading units I've had issues with the transport slipping and fighting to insert or eject the sleeve on its own. In one instance the pin that operates the transport door and the power switch broke and I had to replace it with a steel pin.

For the discs, well as above you cannot clean them but if they were stored stacked horizontally rather than vertically on their sides it's a lot more likely the discs got scuffed.