ZXAM New Interface
                                  © 1996 MSL

WARNING:
Use these files for your own risc!


HISTORY:

The original ZXAM cassete interface requires a mimimum of 80% of volume on
a cassete player supplied with 6VDC. So old and bad records have to pass by
an amplification before. This can damage the port if the zener diode doesn't
cut fast peak (more than 5V).
This new interface needs about 50% only and have more "isolation" between
the audio output and the joystick port.


NEW CIRCUIT:

Was added a switch transistor with DC gain (hFE) between 200 and 250 to
original circuit. Any transistor type can be used like BC547C, BC548C or
BC549C. The 22K resistor have to be changed for others hFE values, otherwise
may cause a bad performance (more hFE, less resistance).

If you don't have experience with soldering and mounting, show this circuit
to any electronics technician. So, good luck! 

AUTHOR:

Mauro Sergio Lourenco
Lourenco@urbi.com.br