[AdamAnt316]

Originally Posted by Electronic M

Speed is determined automatically on all VCRs based on the tracking control linear track on the magnetic tape (read by the stationary head that also reads linear audio track).
The speed button or switch on your VCR is for record mode only.
There is no difference in the tape cassette shell between a pre-recorded tape and a blank (ignoring the notch that prevents you from recording over the contents of a pre-recorded tape....I used to time shift and archive TV on VHS regularly 8 years ago. A normal VHS tape I could and did record both speeds on...Say half hour of SP followed by 3 hours of EP and another half hour of SP... every VCR will allow it and automatically switch speeds on transition.

Clean the tracking head and if that fails try the tape in another VCR and if that doesn't work the tape may have had damage to the control track...if the tape it's self is damaged your SOL.

Thanks for the reply. I did try the "UHF" tape in a different VCR (a stand-alone Sony, probably from the early 2000s) and it detects and plays fine in EP. I tried another EP-recorded pre-recorded tape in the Samsung which started this query, and it was detected correctly as EP. Must be something about the tracking signal on the "UHF" tape which the Samsung doesn't quite like.
-Adam