Optional Upgrades
F256 Optional Upgrades
Opening the F256K case
To open the top half of the case, you will need a torx security size 8 screwdriver bit. To further disassemble the main board and take it out of the bottom half of the case, you will also need a Phillips size 1 bit and a torx security size 10 bit. You can check out the whole tear down operation in this video:
CR2032 coin cell battery for Real Time Clock
(F256K: requires the top half of the case being removed)
Install a 3V CR2032 battery to enable real time clock operations.
CPU integrated chip swap
W65C02S W65C816S 6809 (FPGA on a mini DIP40 board)
Feather Huzzah Wifi module (ESP8266)
Here's a full video guide on how to configure, solder and install an ESP8266 Feather Huzzah module from Adafruit into the F256K, could also apply to a F256Jr.
3.5 mm audio socket for stereo (year one production K and Jr units only)
If you have a Jr or K from 2023, chances are, your 3.5 mm audio socket is mono only by mistake. Here's a way to test this out. Run the following BASIC program:
5 poke $D6A1,4: REM'set PSG_ST register to stereo mode' 10 poke $D600,$9C: REM'silence left channel' 20 poke $D600,$89: poke $D600, $3F:REM'send A2 to left channel' 30 poke $D610,$9C:REM'silence right channel' 40 poke $D610,$8A: poke $D610,$0A:rem'something else to right channel'
while capturing the audio in your favorite modern computer software (ie audacity). If you have stereo, you should clearly see a different tone in each left and right channels. If they're the same mixed tone on both channels, you have a mono socket.
It is possible to desolder the socket and replace a proper one, here are the tips from Stefany: F256K - Your output will be Mono. F256Jr - Your output will be working perfectly, but when you want to install an external audio connector on the front bezel, it is not going to work.
For the F256K, the line that could be cut are on the side of the board which means that one would need to desolder the connector to fix the issue. the fix for f256k is either 1- remove, cut trace, reinstall 2- remove, reinstall the right jack connector with the right connector, the traces become irrelevent
The right part for the socket is: SJ1-3555NG
- pending video on how to swap this socket on the K*
