:CueCat Modifications for model 68-1965A
These are the PCBs that I have succesfully modified:

PCB 0600 MB-BR338FM R0.3
(FM+H Rev 0.3)
JUMPING PIN 2 TO VCC (+5v) is enough to disable encryption. (yellow wire)

PCB 2300 MB-BR338HM R2.1
(HM+H Rev 2.1)
JUMPING all PINs 2, 3 and 4 TO VCC (+5v) disables encryption. (yellow wire)

The modifications on these models models took longer to discover than those of the 1965, but it is easier to work on this ones because you only need to tak off the hood and connect one wire.
Find the 5 holes above the writing with the version.
Pin 1 is to the left, pin 5 to the right.
To disable the encryption, set pin 2,3,4 to VCC.
Pin 5 seems to disable the checksum error detection, meaning, you can scan bits of barcode without getting to the end. This can also cause misreadings.
Pin 1 seems to have no visible effects.
Once you've disabled the encryption, there is no need to remove the memory chip to strip the Serial ID from the string since this is gone for good anyway. Still, if you wish, take the chip off from the PCB where shown in the image of the Bottom side.
For more info about the whole journey into a :CueCat, read here.

All this started thanks to "HaveBlue" and all the others listed on his web site at http://www.airsoldier.com/~cuecat/
If you find this data useful, drop me a line at electrons@libero.it ;-)