RE: C-64 joystick port, pin 7

From: David Wood (
Date: 2003-06-19 10:23:38

On Wed, 18 Jun 2003 wrote:

> I have checked the schematics again.
> The +5V from the 7805 is used only for the video circuits and the timer.

Agreed. rectified from the 9vac suipply right?

> The +5V on the joystick port is connected to the 5V on the external power
> supply.  This is fused at 5A, so I don't think I would short it to ground.

you repeat 5A.  What sort of power supply do you have?  I remember my stock
psu having a modest 2-3 amps.

> The 9V AC is fused at 3A in the external power supply.

Not all PSUs have this 3A fuse inside them.  My repairable one from
grapevine didnt, and I dont believe the brock psu (my 2-3amp 5v unit I have
in mind) did.
> There is an additional 1A fuse on the 9V AC line that feeds the 9V AC on
> the ussr port and the rectifier bridge that supplies power to the 7805.


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