Finally I found some time to test the battery pack. For testing purposes I ordered a 12V 2.3Ah lead-acid battery which fits into the compartment of the original battery. Unfortunately I was not able to get a 3Ah but it will do its job.
After charging the battery with my charger from my convertible I prepared a cable with the correct DC connector. Its not easy to get a DC connector with 3mm inner pin and I probably change the connector to a more common part.
Connected to the sound machine (e.g. the parts of unit 4 just laying around) everything works as expected. Cannot wait to finish and to take it on a brief trip.
In the meantime I just want to finish the missing video of the third part of the tape mechanism and new videos of reassembling the unit…
