I'd be very skeptical of a 35yo pinchroller.

Arbilab-

Thank you for the notes about the control track and testing. I will see what I get from recordings at both speeds.

Johnny-

I did not mean to make your comments unwelcome. Despite a lot of VCR repair work years ago, I never got to the point of needing to do mechanical alignments, so it is new territory to me.

My Photofact manual does have the mechanical alignment instructions (and in fact, it also has the electrical ones that Tom posted, which I did not find the first time I looked through it). The proper mechanical alignment requires a whole bunch of specialized jigs that I do not have and probably could not get even if I tried to at this point. Absent those, my plan B needs to something less complete. Since the machine plays BI tapes properly, instantly, every time, but BII has the problem just about every time, I do not understand specifically what is going on here. Johnny and arbilab, when you worked on these VCRs, did you have those Sony jigs and devices? Or, are there "real world" methods of working that cannot be described in a service manual? Do either of you remember seeing this same problem? Thanks.

I wasn't planning on posting anymore to this thread, but here goes.

Those VCRs are getting old, like really old. You can't expect the rubber and lubricants to be good. Everything, and damnit, I mean EVERYTHING will effect tape path alignment. Turning a few controls and expecting stellar performance is like hoping to win the lottery; it ain't gonna happen.

Many of those decks needed a complete overhaul after 1000 or 2000 hours of operation. That means all the rubber replaced (pinch roller, belts, idlers). The guides would wear--these are rollers that ride on metal shafts; often times the only way to determine if they were affecting operation is to replace them, so they were normally-stocked items. Same with CTL heads, spindles, capstan motors and a dozen other mechanical parts. The tension bands are critical; when these wear the take-up and back tension jumps around like a politician running for re-election.

I haven't worked on a 8200 in years; I don't even remember if they had tension bands, or all the procedures for alignment. I do remember one thing: being a tech ain't easy. If you want to hear that adjusting a couple of controls will fix your problem, you won't hear it from me.

The reason that I tended to discount this type of thing as the cause of the problem is that if it happens during playback then it should also happen during record. And if the recording is bad than you should never be able to get a good playback. And the machine always plays back correctly for one record speed. And for the other record speed it can be kicked into playing back correctly, and once playing back correctly it will play back correctly until the playback is stopped. If tape path problems were causing the tape to slew up or down on the audio/CT stack then I don't see how you could ever get a good playback.

If the tape is slewing up or down on the audio/CT stack then I would think that you could see it doing that while watching the tape move. Perhaps it is time for a good sharp look see.

Edit: Posting at the same time as Johnnysan

I think that I should explain where I am coming from here. I have a Sony SL-5200 where the electrical adjustments used to regularly drift out of spec, rendering the machine unusable. Adjusting the electrical adjustments would restore the machine to operation. I finally replaced all of the small value electrolytics in the servo system (1uf and smaller) with regular film capacitors and did one more electrical adjustment. I have not had problems since. Now this machine definitely has less than 1000 hours running time.

I do know that the back tension is extremely important. The machine would do fairly well with tapes that were recently recorded but would not play tapes that were made when it was new. Fixing the back tension restored the ability to play old tapes.

As George Takei as Mister Sulu on Star Trek might say, "Oh My!" That's why I didn't jump into this right away.

Yes, you need to look VERY closely at the tape path. No, I did not have the factory jigs. But as I said--and I owned one that did this--the factory didn't necessarily get it right EVEN WITH the jigs. And even presumably knowing what they were doing. Neither did the warranty service shop, where I took it twice.

If 2 former Sony techs say it can take all afternoon to align one once you know how, how long do you suspect it might take to learn what all to look at determining alignment? I could show you in person but the detail is prohibitive in text.

Sport that I am, I'll still try. Every time the tape passes a surface (guide, head, drum, capstan) it must be PERFECTLY FLAT. Get a mirror and a bright light and look at the reflection of the tape sheen, with particular attention to the edges.

If I spent another 2 dense paragraphs explaining why these things are more evident in BII than BI, you'd just become more befuddled. Take my word, get a bright light and get to squinting best you can. Look at the edges.

These notes are precisely the type of detailed information I was looking for. I really appreciate the help from your experiences.

If you feel like having your daily cringe, read on. I have a Sony SL-2406 Beta Machine I bought new in 1984. One day it decided to begin playing/recording and then stop in both playback and record modes so I dropped it on my bench to see if I could locate the problem. After futzing around with it for a while, I thought I found the problem so I retrieved my hammer and chisel and attacked the board that had issues. It turned out to be the motor built into the circuit board. The motor is actually a part of the board, not a separate motor attached to the board. The rivets stabilizing it had worked into a loose state, allowing shifting and unbalancing and with a few well applied whacks with the hammer and chisel, I tightened the mounts and the VCR is still working today. I have some tapes that cannot be replaced or copied so I need to keep the old Beta machine handy if we want to view them. A rather unconventional repair method but it is what was needed at the time. Check that your motor is secure since that will stop the machine from operating.

I hope it's enough to run with Chris. Time and patience will be required.

If you find edge deformation at a surface, it's more likely the problem is the previous surface in the path than the one where you see the problem. The pinch roller/capstan is an exception to that rule and especially applicable to this problem as it can have a strong slew bias that affects the preceding A/CT head stack. The stack itself is not likely off but anything is possible because there's no telling who's been in there tweaking what.

Get a new pinch roller if possible, and confirm there is no binder deposit on the capstan*.

*I should have said that first because it's the simplest and might be the whole problem.

Bugman is talking about the type of capstan motor in which the rotor and stator are separate. He is simply lucky to have found one that could be repaired in the manner he described. The 8200 would not have that problem.

Yikes!

Sorry if my posts had you checking the wrong things first. Perhaps the SL-5200 is the only machine that uses electrolytics as timing capacitors in the servo circuits, where any change of capacitance will cause the adjustment to go out of spec.

If you do find tape path problems, do not adjust anything until after you verify and adjust the back tension. It does seem that the back tension is always too low. I made a back tension measurement jig out of a supply real with a little tape on it from a old cassette. I used one where the tape had been damaged. You will need to come up with a spring tension gauge or some way to measure a tension of around 50 grams. I attached some music wire to a piece of wood and calibrated it with known weights.

Edit: Again posting at the same time as other people.
Certainly check the pinch roller and capstan. The thing I was cautioning against was moving any of the tape guides and such.

Well Tom, in your first post you had him adjusting several things (which I warned against).

Now you say don't adjust anything until he verifies back tension and checks the capstan and pinch roller.

If you have a scope you can make the electrical adjustments with close to zero chance of getting lost and messing things up. And I did advise him to mark the positions of the pots so he could put them back to the as found settings. If you start adjusting the tape guides, it is much harder to put them back where they were. And if the back tension is wrong you can not correctly make any of the other tape path adjustments. You can make the electrical servo system adjustments even with a completely messed up tape path.

Not a problem, Tom, that board did need those adjustments in any case (which I did with scope and frequency counter as required).

Before I started this discussion, I cleaned and relubricated the capstan as in my SL-7200 service manual, so I know there is no debris/buildup on it at least.

Since I have two of these machines here now, I am going to finish all of the basic maintenance (new belts and tires, clean and replace old grease) on the second machine before closely working on the tape path. I just picked up the rest of the rubber parts yesterday, so I should get moving again within the next couple of days.

I was a vcr tech in that era.
I would look at the tape path alignment, it is very critical.
Remember the control trac is recorded on the tape so do not rule out a bad tape.

Good Luck

Thank you for the comments, bauerdental. I have been busy on other projects so I have not yet got back to the VCR work. I did try different tapes and did not see any obvious difference in performance (except that installing the one servo board from the second machine allowed the first one to often lock on to tapes made on other machines, which it did rarely if ever with its own servo board). The adventure will continue soon, I hope...