Safety Record Switch

[Chip Chester]

If the machine is put together enough to run, maybe try this:

For the record tab, get a cassette whose content you can record over, but with the record tab removed, and make up a plastic shim and attach it to the non-sticky side of a post-it note. Place it over the record tab location with the sticky side of the post-it, and use a string or piece of tape to pull it away while recording is underway. See if it just stops, stops and ejects, or just drops out of record.
It could be that the switch mechanism is worn just enough that the slight extra thickness on the record tab 'cures' it. In that case, a shim or spacer at the right place in that mechanism (not on the cassette itself) could make it all better for the next 25 years.

Also, don't overlook a tensioning issue. If the tape path loses tension, the next thing I would have the deck do, if I were the designer, would be to have it eject because that would protect the tape the quickest -- get it unlaced, away from the spinning head (which would eat an un-tensioned tape) and back safely in the cassette.

Good luck! Just be systematic about your testing, and you'll get to the true cause.

Chip

[Electronic M]

Originally Posted by Chip Chester

Also, don't overlook a tensioning issue. If the tape path loses tension, the next thing I would have the deck do, if I were the designer, would be to have it eject because that would protect the tape the quickest -- get it unlaced, away from the spinning head (which would eat an un-tensioned tape) and back safely in the cassette.

Chip

I've seen enough dead take up troubles to want the deck to try to pull the tape back into the cassette and stop there. If the take up did not work and the mech tried and failed to pull the tape in it is better to give the user a chance to put the deck into un-threaded rewind or fastforward (if either works) to ensure the tape is back in it's shell and won't get crinkled by hanging out of the cassette on eject...