Sony SL-5200 Servo / Video Problems

I doubt it's a capacitor issue. I will speak from Betacam SP deck experience here:

The problem seems to be electrical to me. Hopefully you've got the service manual - dive your nose in there and check what components/ circuits are unique to each playback speed. It probably has a separate circuit for the B1 speed, another for B2, etc.. Check EVERY component that is unique to that circuit! Pull them out of the circuit if necessary. If there are any large power transistors involved, I would even go as far as measuring the hFE and making sure it's at least >25 (you will need a good DMM). It's also possible the B2 speed adjustment pot is bad! I've had a serious head-scratcher once where this was the case.

If the problem is mechanical then the capstan motor might have met its end. Motor windings in general become stressed over time due to heat (the insulation starts to fail) and you'll find that it takes more and more current to achieve the same speed. You can try shoving more current into it with jumper wire from a viable current source to bypass the limitation of the adjustment pot, but that's not advised unless you're very careful! This will accelerate the motor's decay and possibly let loose some "magic smoke".

Check the friction of the capstan shaft by spinning it with your thumb; it should spin freely and come to a stop slowly! I don't know how difficult it is to remove, but try removing the capstan assembly and giving it a thorough cleaning. Compressed air will be a godsend here. Excessive tape tension could slow down the capstan motor, though it would definitely slow the drum rotation too so I doubt that's the case. Does this thing have a pinch roller? I'd take a close look at that if it's present - too much/too little pressure could cause problems.

I'm going to bet that if the capstan motor hasn't been replaced yet, it's definitely time! As far as the video issue on B3 goes, fix the capstan speed on B2 first. It's possible there could be more wrong with the VTR but you won't be able to accurately diagnose it yet, especially since the two problems may be related. Oh and I think it should go without saying but make sure you're always using fresh adjustment tapes. Sometimes I forget they have a limited lifetime...

Curious to see what happens!

-Julian

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I think I'm going to have to invest in an ESR meter before going much further on this thing.... it's hard to say how many caps may be faulty. I can't find any factory alignment tapes, all I have are some prerecorded movies etc. I also have an SL-5020 which works, so I may swap parts like the capstan motor and see if that narrows it down. I've set this aside for now while I catch up on some more important projects, but when I get back to it I'll try to post an update. Thanks for the info.

The problem seems to be electrical to me. Hopefully you've got the service manual - dive your nose in there and check what components/ circuits are unique to each playback speed. It probably has a separate circuit for the B1 speed, another for B2, etc.. Check EVERY component that is unique to that circuit! Pull them out of the circuit if necessary. If there are any large power transistors involved, I would even go as far as measuring the hFE and making sure it's at least >25 (you will need a good DMM). It's also possible the B2 speed adjustment pot is bad! I've had a serious head-scratcher once where this was the case.

If the problem is mechanical then the capstan motor might have met its end. Motor windings in general become stressed over time due to heat (the insulation starts to fail) and you'll find that it takes more and more current to achieve the same speed. You can try shoving more current into it with jumper wire from a viable current source to bypass the limitation of the adjustment pot, but that's not advised unless you're very careful! This will accelerate the motor's decay and possibly let loose some "magic smoke".

Check the friction of the capstan shaft by spinning it with your thumb; it should spin freely and come to a stop slowly! I don't know how difficult it is to remove, but try removing the capstan assembly and giving it a thorough cleaning. Compressed air will be a godsend here. Excessive tape tension could slow down the capstan motor, though it would definitely slow the drum rotation too so I doubt that's the case. Does this thing have a pinch roller? I'd take a close look at that if it's present - too much/too little pressure could cause problems.

I'm going to bet that if the capstan motor hasn't been replaced yet, it's definitely time! As far as the video issue on B3 goes, fix the capstan speed on B2 first. It's possible there could be more wrong with the VTR but you won't be able to accurately diagnose it yet, especially since the two problems may be related. Oh and I think it should go without saying but make sure you're always using fresh adjustment tapes. Sometimes I forget they have a limited lifetime...

Curious to see what happens!

-Julian