Re: Commodore PET 3016
The CASS_WRITE signal on pin E5 of the cassette connectors JP3 and JP6 and on pin 7 of the user port appears to originate from the 'user port' 6520 pin 13 (PB3). You could try checking that the connection between that IC pin and those three connector terminals is intact, as it should be.
I'm not familiar enough with PETs to know whether the CASS_WRITE signal is a digital data stream which is converted into audio tones inside the cassette unit, or whether the CASS_WRITE signal is TTL-level audio tones. Does anyone know?
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