Some suggestions:
1) Press the button to the side of the cassette flap and lift it to check for tape edge damage. If it's curled that may be the problem and prevent playback on most VCR's.
2) The recording may only have a mono soundtrack but you are connecting to a stereo line in your TV (scart).
If there is an audio button on the VCR remote control, switch the audio output to L + R. Choices may be Off/L/R/L+R channel audio. Otherwise, connect to TV using RF only instead of AV.
3) The tape path on one or more of the machines is not aligned correctly.
Cobweb
October 2005