[Atari 600XL - Upgrade to 64k]

That makes for a really slim 800! Congrats =D

 

btw, nice avatar NISMOPC ;-), I made that Atari graphic with red background back sometime in 2006 =)

Googled it 

 

Thanks!

[Atari 600XL - Upgrade to 64k]

Yea, the bottom two purple wires were soldered to the trace lines instead of the actual chips, but I would be interested to know the difference between my pink wire connected to the resistor vs. your small jumper wire on the chip. 

Apparently there is more than one way to skin the cat.

 

EDIT: You can skin the cat more than one way ;-) Just found this post asking the same question and here is one reply:

 

http://atariage.com/forums/topic/187900-strange-600xl-ram-expansion/
 

 

 

i just looked over your pic and a schematic, and the U5/U6 to U15 wires are the same as D->C and K->J, and the other jumper just accomplishes the same as the wire from the resistor to U16 in another method...

[Atari 600XL - Upgrade to 64k]

Just did this same upgrade last week as well as a basic composite out mod and added an internal USB cable to install an internal SIO2PC FTDI board.

 

Such a nice little unit. 

 

64K Upgrade

 

Composite and USB mod

 

Composite mod (enclosed in RF Modulator case)

 

Rear Composite A/V Out and USB Out

 

Completed Unit