Screen is black
Q: The system does not start. The screen remains black.
A1 (GRAMKracker): You have activated the GRAMKracker support, you have set the GK DIP switches to point to GRAM 0 (instead of OpSys), and you have not inserted the GRAMKracker cartridge, or the cartridge is empty. Please read the GK manual.
A2 (HSGPL): You switched on the HSGPL without previously uploading an operating system to the HSGPL. As the HSGPL is always active for the SGCPU, you will encounter the same problem there.
The HSGPL is a buffered memory card which replaces the console's ROM and GROM content. When you turn it on, MESS automatically unplugs all memory in the console until you turn off the card again. When you buy an HSGPL card you get a preloaded system. To achieve this in MESS, you have to set the HSGPL configuration switch to "Flash". This allows access to the card but prevents it from taking control. Now you can use a tool like DSRLDR to flash the (emulated) ROMs on the card using a ROM package. When done, you must copy the desired operating system version from the backup positions in the card to the location expected by the system (ROM and GROM). I have written a simple tool to perform this step. Finally, put the switch to the "on" position and reset the emulator.
The HSGPL was sold by the System 99'er User Group (SNUG), so you should ask them to provide you with a suitable ROM package.
Strange looking selection list
Q: My cartridge selection list contains unreadable characters and colored boxes.
A: You have plugged in the GRAMKracker cartridge, but you have not switched the cartridge system to "GRAM Kracker" mode. Check the DIP switch menu.
Q: My selection list only says "INSERT CARTRIDGE".
A: You have activated the GRAMKracker support, but no GRAMKracker cartridge is inserted. This is a RPK file like all the other cartridges and contains the ROM of the GK. Some were reported having the name "mg_gramkracker.rpk". You can plug in the cartridge at any slot; the guest cartridge goes in any other slot.
mess ti99_4a -cart1 mg_gramkracker.rpk -cart2 ti_invaders.rpk
RS232/PIO output hangs
Q: When I try to output a file through RS232 or PIO, the computer seems to hang.
A: You have probably forgotten to "insert" an image into the RS232 or PIO device. Check the file manager and define an output file (similar to inserting a disk image into a drive). When printing to PIO or RS232, the contents are appended to the image file.