Need help and manual for late version Tektronix 212 oscilloscope!

[5065AGuru]

Hi, Just got in a nice Tektronix 212 dual trace oscilloscope. It powers up OK but has a problem with triggering. If I display a 2 div P-P waveform and trigger on it it's fine but if I use the vertical position pot to move it up or down by more than a division or so it stops triggering. I can readjust and get it to trigger at the new position. This occurs using either channel 1 or channel 2 only as well as when in dual trace. If I put the same signal in both traces I can only get good triggering when they are sitting on top of each other. trying to move either traces position causes the triggering  to fail. I down loaded the manual off of Tekwiki and started looking at the schematics and found another problem. All the on line manuals I can find are for the lower serial number units (<10xxxx). These units have the channel off switches built into the two vertical position pots. My unit SN B200967 does not have these pots or the legend by the pots showing off. Pulling the top cover does indeed show a different part number for the pots and no switches.
So I'd first like to find a manual that is correct so I can troubleshoot further. Can anybody help there or advise on the problem? I also noticed that on the vertical mode switch that if you slide it up to the channel 1 position it internally covers up the auto preset hole! Do the older SN units do this also?
You can also see the new vertical mode switch and relocated trigger source switch on the new versus the old SN PIX.
Cheers!

Corby

[edavid]

Artek has the later manual for $12.50:  https://artekmanuals.com/manuals/tektronix-manuals/

I haven't found a free copy.

[5065AGuru]

Thanks for the info! Ordered one from them.
Cheers,

Corby

[ondraN]

I have 212 and 214 in my collection. Both are from the new series and do not have an on/off switch on the sync potentiometer. And both behave exactly like yours. Another special feature of them is that when the track is moved vertically, the horizontal position also changes. So if I have waveforms of the same signals, when I move one or the other track vertically, the phase seems to change. But it is intentional. I guess it improves the visibility of the signals in a two-channel display.