on both decks, the auto revese feature doesnt work

It sounds like your cassette deck's auto-reverse mechanism isn't functioning properly. This issue is often caused by worn-out belts, misaligned gears, or dried lubrication in the mechanism. Here are a few troubleshooting steps you can try:

1. Check the Belts – Over time, belts can wear out or slip, preventing the deck from properly switching sides. If possible, inspect and replace them.
2. Clean and Lubricate Moving Parts – Dust and dried grease can cause mechanical failures. Carefully clean and lubricate the auto-reverse mechanism.
3. Inspect the Head Rotation Mechanism – Some decks use a rotating head for auto-reverse. If it's misaligned or stuck, it may need adjustment.
4. Reset the Deck – Try unplugging the unit for a few minutes and then powering it back on to see if it resets the mechanism.
5. Seek Professional Repair – If the issue persists, a technician may need to inspect the internal components.

You can find more details on similar issues here and here. Let me know if you need help with any of these steps!