Posted By
weidi
on 2021-12-20
10:28:26
|  Re: Cartridge port Not working correctly
It is really strange, but:
I don't see reason why on "good" system
voltage could be above +5V Vcc.
Plus/4 should be able to work on +5V only (no Datasette use).
So it is possible to test voltages when ~9V AC disconnected, only +5V coming from power supply.
When it works OK on +5V only that means there is "voltage leak" from ~9V AC or +9V unreg.
+9V unregulated can go to the system thru broken TIP 29, U6 (7406) or some shortage on the board.
|
