User's Manual

27
8.6 CPU (Microprocessor) Trouble
Start
↓
Supply power again.
Is the LCD turned on?
↓
Is start alarm sound made?
No
→
Is a start alarm sound
made once?
No
→
Check the power connection status
as well as U509 and the EEPROM
(U501) data.
Yes↓ Yes↓
Press Monitor button. Is
the green lamp is turned
on and is sound made?
No
→
Yes↓
Press the PTT switch. Is
the red lamp is turned on
and does transmission start?
No
→
1. Is there a power voltage?
2. Does the X10 (4.032MHz) oscillate?
3. Check if there is any trouble in the PLL and the
VCO.
4. Check if there is any data error in U501
EEPROM.
5. Check the CPU and other circuits.
Yes↓
Trouble in other parts