Loading Tips

If you are experiencing issues with loading or running programs from USB on THEC64, try the following tips.

Loading issues

Your program isn’t loading on THEC64 or THEC64 Mini. It either doesn’t load at all or only partially loads before stopping or failing.

  1. Turn off the ‘Fast loader’ option in Media access or File loader by pressing button C on THEC64 Joystick. Now try loading your file again
  2. For d64 and g64 virtual disk files only, try adding an AD flag to the filename (see CHAPTER 8 in THEC64 User Manual, or see here for THEC64 Mini). This enables accurate disk mode, at the expense of longer loading times. Try loading your file again
  3. For any type of virtual disk file, try adding an RO flag to the filename (see CHAPTER 8 in THEC64 User Manual, or see here for THEC64 Mini). This enables read-only mode, which prevents any files from writing back to the virtual disk file. Try loading your file again
  4. Some programs will only load on a PAL or an NTSC computer model. Add a TN (for NTSC) or TP (for PAL) flag to your filename (see CHAPTER 8 in THEC64 User Manual, or see here for THEC64 Mini). Now try loading again.
  5. The program file is faulty, corrupt, incomplete, etc. Some programs could have been altered from the original and no longer operate correctly. Source a different version

Remember that you might have to combine various permutations of tips #1 – 4 in order to get your program to load, e.g. _ADROTP, or _ADTN, etc.

Running issues

Your program loads, but it isn’t appears as though it is running incorrectly. This could appear as visual problems, audible issues or non-responsive controllers.

1. The joystick or controller isn’t responding.

Try specifying a different joystick port, as follows:

1.1 THEC64 range defaults to using joystick port 2 (for the C64 computer). Add the J1 flag to the filename and load the program again to try port 1 instead

1.2 The VIC 20 only had one joystick port, so there is no need to specify a joystick port via filename flags on the full-size THEC64. The VIC 20 program might not use a joystick at all (although you can map key presses to the joystick and therefore use one if you create a cjm file instead)

Note that if you use cjm files, then you have to include an entry for the joystick(s) for the program else joystick control won’t be available.

2. The screen is flickering or is showing jerky scrolling.

The program is most likely expecting to be run on a different computer model. Add either a TN (for NTSC) or TP (for PAL) flag to the filename and try loading your file again

3. The music sounds wrong.

Some programs run fine on either an NTSC or a PAL computer model, but the music was usually written with one or other specific video frequency in mind (50Hz for a PAL computer or 60Hz for an NTSC). Many programs don’t account for this difference, and so music intended for an NTSC model plays slower on an original PAL C64 at 50Hz, and music intended for a PAL model plays faster on an original NTSC C64 at 60Hz. The pitch of the music is also affected by this speed difference. If you only ever experienced a program running at 50Hz on a C64 computer for example, then you wouldn’t necessarily know that the music was actually running at a different speed (slower) than it was meant to.

Unlike the original PAL and NTSC C64 computers that output video at a fixed 50Hz and 60Hz respectively, the full-size THEC64 will run both PAL and NTSC models at either 50Hz or 60Hz, depending on the capability of your HD TV and which Video output setting you choose. It is the 50Hz or 60Hz setting that affects the speed of the music rather than the chosen PAL or NTSC  computer model, as you might otherwise expect.

HDMI Video output Computer model Program version Music speed Music pitch Auto audio scaling
50Hz PAL PAL True True
50Hz NTSC PAL True Higher Yes
50Hz PAL NTSC Slower Lower
50Hz NTSC NTSC Slower True Yes
60Hz PAL PAL Faster True Yes
60Hz NTSC PAL Faster Higher
60Hz PAL NTSC True Lower Yes
60Hz NTSC NTSC True True

As the table shows, running a specifically written PAL version of a program on an NTSC C64, or a specifically written NTSC version of a program on a PAL C64, will affect the pitch of the music. This is exactly the same as would happen on the original C64 computers.

Because THEC64 can run a C64 computer model at a video output rate that is impossible on an original C64, THEC64 applies an automatic correction to the music, called audio scaling. Without doing so, music would sound higher when running a PAL computer model at 60Hz output and lower when running an NTSC model at 50Hz (this is THEC64 Auto audio scaling shown in the final column of the table). This correction is unable to adjust the pitch of sampled audio playback and will therefore make SID (generated) audio out of tune with the sampled audio. For this reason, audio scaling can be disabled by adding an NS flag to the filename.

For the best experience, you should initialise THEC64 to match the video output native for your region. This means that if you reside in North America or owned an NTSC C64, you should select the 60Hz video output setting. If you reside outside of North America or owned a PAL C64, then you should select the 50Hz video output setting instead. Note that not all HD TVs are capable of displaying at 50Hz, in which case THEC64 will default to 60Hz and not give you the option to change to 50Hz.

If you think you have selected the wrong video output rate, you can re-initialise your THE64 by holding down the power button until you see THEC64 logo. THEC64 will then guide you through the initialisation process again. You can also perform a factory-reset via THEC64’s screens, but that will delete all of your saved games as part of the process.

4. Graphics or info in the top or bottom border is not in view at all, or is partially off the screen.

Precise up-scaling from the original screen resolution of the C64 or VIC 20 to modern HD standards means that the borders don’t quite fit into the 720p HD display. If your program needs either the top of bottom border, then use a cjm file to vertically shift the display up or down a certain number of display lines. Alternatively, sacrifice the precise up-scaling and squeeze both borders into the 720p displayed image by adding the FH flag to the filename (see CHAPTER 8 in THEC64 User Manual, or see here for THEC64 Mini). Now load your program again.