For an old TEAC tape recorder/player, nothing is more appropriate - esp. if it has been sitting gathering dust for a while - than these measures in this order:
1. clean - the tape heads, so the head gap isn't gunked up. This can be done with the sortof small alcohol pads used to clean a spot of skin medically, or a clean fine soft lint-free cloth moistened in alcohol, if you cannot get the former.
Try it out - see if it records....then
2. de-magnetize the record heads.
then if that doesn't work
3. either replace the heads, or troubleshoot and if needed repair the recording circuitry immediately behind the record heads.
That's an outline, I realize, but hopefully the step (1) above will be all that is needed, or perhaps step (2) also.
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