Atari 600XL Recap


Original capacitor values and sizes. h=height, d=diameter, r=lead spacing, l=length(axial).



64K Memory upgrade

A standard Atari 600XL has 16K RAM memory, but its easily upgraded to 64K.

* U11, U12: Replace 16K DRAM with 64K DRAM (64K x 4 bit)
* U5: Lift leg 3, connect to pad ( A15 )
* U6: Lift leg 10, connect to pad ( A14 )
* U16: Lift leg 8, connect to R36
* R36: Lift leg and connect to U16
After the modifications above, PRINT FRE(0) should return 37902. You can also launch the 600XL self test by holding OPTION while powering on.


Leg lifted out of the socket. Desolder the IC:s and add sockets if they are not socketed.



S-Video Modification


Atari 600XL PAL was not shipped with S-Video, this mod restores it to the same pin-out as some of the other Atari models. There are some variations for the S-Video mod, but this one was chosen for its simplicity and it gives a good picture quality. Note that this modification removes the composite video output.


1 – Remove R137
2 – Remove C112
3 – Remove C109


4 – Cut PCB trace between legs 2 and 5 on the monitor port connector.
5 – Solder 75 ohm resistor from Pin 1 to transistor Q6 emitter.
6 – Solder 75 ohm resistor from Pin 5 to transistor Q9 emitter.



Power supply replacement

I replaced the original powersupply (rated 5V, 1.5A) with a new +5V switched powersupply.

64K upgrade :
S-Video :