
7 Troubleshooting
In case of problems with the CT800, there are several ways of diagnosis and possible
remedy.
7.1 Power-on Self Test
During power-on, the CT800 checks some hardware functionalities that might fail. A
dialogue box will tell about one or more system faults if any are detected:
•
ROM
: the checksum of the firmware is wrong, so stable operation is not
guaranteed. Download the firmware image again and make sure that you use the
one with appended checksum. Use the “verify after download” functionality of your
programming adaptor. If the problem persists, the hardware is damaged and has to
be replaced.
Note: a side-effect of a bad firmware checksum is that overclocking (see chapter
5.6.3. Turbo
) will not work anymore. The CT800 uses a firmware check for verifying
correct system operation when going overclocked, and if the checksum is bad to
begin with, this system stability check will fail.
•
RAM
: the internal RAM test failed. The hardware is damaged and has to be
replaced.
•
CLK
: the external quartz oscillator does not work. The system will still run nearly as
normal, albeit with slightly less precise timing. At room temperature, a tolerance of
about 30 seconds per hour can be expected. This is a hardware damage, and the
quartz oscillator has probably been damaged during production.
•
KEY
: one or more keys are in “pressed” state. Either the user has been pressing a
key during power-on, in which case there is no actual problem, or the hardware is
damaged and has to be replaced since the keypad will not work.
30 / 32