I seriously, seriously doubt he's going to find a TV yoke that's going to work with this chassis. Remember, this is a medium resolution monitor... He's going to have to change the yokes.
Things you need to look for in choosing a replacement tube:
- Physical size. Make sure the tube is actually a real 25" tube, the tube number should start with a 63, which denotes the size in some wacky foreign measurement - centipedes or something.
- Neck connector/pinout. The neck connector needs to be the same as the arcade tube. Easy way to verify this by looking it up in the B&K tube tester manual and checking to see if it uses the same tester adapter as the arcade tube. Most arcade tubes use CR23 or CR31. Neck diameter goes hand in hand with the connector - CR23 tubes are "wide neck", and CR31 is "narrow neck".
- Mounting. Some television sets have different positions for the mounting ears, which will require fabrication of spacers to mount the tube into the arcade frame. (i.e. the tube ears are too far forward) Just be sure when fabricating spacers, that if you use wood, you still need to ensure the dag ground strap makes good electrical connection to the metal frame. This is usually accomplished by the strap looping around two opposite tube ears, which then get bolted to the frame. The metal bolts should make a sufficient ground, just ensure that your spacers don't interfere with that, and double check. Sometimes the bolts screw into "keep nuts" clipped into the frame, which may or may not make a good electrical connection.
Edit: I would start by checking the newer TV first. An old enough set will have a delta gun picture tube, which won't be usable. Besides, wouldn't you rather keep the older set around and working so you can play your Atari 2600 on it?
Also, another thing to check - deflection angle. Some TV tubes are shallower than the arcade tubes. Arcade tubes for 25" monitors are 100 degree deflection, 19" tubes are 90 degree, with the obvious exceptions on vector monitors. Most modern 25" sets are 100 degree as well, but I've seen some 110 degree ones. It'll be obvious by comparing the two tubes - they look a lot different. Electrically they'll still work, but you might not be able to get it to converge.
-Ian