old leaky caps on the servo board will cause playback issues, usually off speed playback which will cause tracking lines to go up or down the screen, with wow and flutter.. Adjusting the pot switches may help, but that's not a fix..

Thanks, tvcollector. I did replace all the low-value tantalum caps on both servo boards and did the servo electrical alignments without a change in the behavior. Surprising, though, I can put in the one servo board from the second machine and then the (first) VCR definitely works better (servo lock on BII tapes most of the time rather than just occasionally), but it is not solved. Are you referring to tantalums or others? I hope to put in some good time on these machines in the next few days.

I think the most problematics are the electrolytic caps.. I know that's the issue with the SL-5000 models...

OK. I did test all of those and they were good on my meter.