PM790 Radio Maintenance Manual
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backlight is off, the current is about 300mA. To test the USB data cable, it must be connected
before power on so that it can be detected. The LCD displays the accessory icon, USB will
automatically turn on. Each function button responds normally, the radio transmission will be
started after pressing the PTT button, the call is normal. The volume & channel knob responds
normally.
6.3No Power On Current
No power on
current
Is the battery or
power supply voltage
more than 12V?
No
Replace
battery or
power supply
Yes
Replace the
main PCB
Is the power on
button normal?
No
Replace the
keyboard
Yes
Measure if the TP26
level of the main PCB
is 0 when the power
button is pressed?
No
Replace the
keyboard
and FPC
Yes
6.4Power On Failure and Current Over 1A
Summary of Contents for PM790
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