Please note: The flash chip SST39F010 has been marked End Of Life (EOL) by Microchip. If the part on the list is out of stock, search for SST39F010, 020, or 040 in the 32TSOP package. They should all be compatible. And please let me know if a part on the list is out of stock!
Recommended Workflow
I highly recommend building the cart in this specific order, to allow you to troubleshoot the minimum number of components at once if issues arise during your build.
Verify the MCU is functioning correctly (1). When powered up in a Game Boy, the LED on the board should flash in a 1 second interval.
Solder the flash memory chip, and it's decoupling cap (2).
Flash the Orange FM ROM to the cart with GBxCart or a similar cart writer. You can find the latest ROM in Downloads
Checkpoint - At this point the cart should boot. Confirm the cart boots - the startup will get stuck at "BOOTING COMM", this is expected.
Solder the digital logic section between the MCU and the flash chip, including supporting caps and resistors (3).
Checkpoint - Now try the cart again - it should now fully boot up into the radio display, and the current station will be shown as 143.3 (or a similar nonsense station). This means the ROM and MCU are successfully talking to each other from the digital logic section!
Next, solder the middle radio section and support circuitry (4). If you do not solder the jack at this point, close the solder jumper underneath the J3 footprint in order to continue testing the cart.
Checkpoint - The cart should now be able to talk to the radio chip, and should be able to tune to stations. You should see valid stations showing up. Try seeking with "A" to confirm functionality. At this point, there will be no sound output.
Solder the cart output section (5).
Checkpoint - The cart should now have audio output through the Game Boy on systems that support it!
Finally, solder the headphone amp section (6), and solder the AMP jumper to the YES position. If you don't plan to install the headphone amp, solder NO.
Checkpoint - The cart should now have headphone amp output! Press "B + Start" to turn on the amp.
Check out the manual to learn more about Orange FM.
Discord
If you need more assistance troubleshooting your DIY build, or just want to chat about Orange FM, check out the Orange GB Discord server.
Shell Trimming
To fit the Orange FM PCB into a shell, you'll need to trim part of the plastic off the shell to fit the headphone jack. A Game Boy Color style cart shell is the easiest to trim, but you can also use a original Game Boy style shell. Here are some photos of the trims required for a Game Boy Color style shell (Click to view larger). This trim was performed with flush cutters, a craft knife, and small files.
