SLO-420. Industrial version of the
SL-2500, minus the tuner.
Problem: This is caused by the little plastic gears wearing. Sony switch
them to metal. Technicians used to see these VCRS pretty common back in the
1980s and 90s, due to this problem.
Audio and Video
Heads: Audio heads to wear easy on these models which cause weak audio.
Video heads tend to cause a fuzzy picture even if a tape is play with a
small portion of tape wear. Video head cleaner will fix this problem.