Troubleshooting - Toa MA-725F Service Manual

TROUBLESHOOTING

Standard machine startup status and process:
1. Plug in the power, turn on the power switch
2. Blue POWER light is on for lasting 2 seconds
3. CH1. CH2. CH3. CH4 PROTECT red lights are on
4. When the 4 PROTECT red lights are on, the blue POWER light starts to flash 2 times (There is no
PROTECT red light with MM-700F.)
5. Blue POWER flashes to the 2nd time, the internal Relay of the machine is on
6. After the Relay is on for 2 seconds, 4 PROTECT red lights are off, and the INPUT SELECT green light is on.
(There is no PROTECT red light with MM-700F.)
7. Finish the startup.
・At this time, the power consumption of the machine is about 49 W (MM-700F is about 6W)
・Open the top cover and observe the internal light:
Top left corner MA-725F BGM BOARD red LED should be flashing
Lower right corner MA-725F POWER SUPPLY BOARD Red LED should be light constantly
Machine Defective Judgement:
FUSE works, but the blue POWER light is not on after power is on, the machine does not work.
Machine does not work
Remove the rainbow cable from BGM BOARD CN7303:
Measure Pin 5 to chassis voltage: No 3.3V
Measuring Pin7 to chassis voltage: No 5 V
The machine startup process is good, but there is no output with the speaker, POWER SUPPLY
BOARD Red LED is not on:
Remove the red and black lines of the POWER STB BOARD CN202 and measure the voltage
at both ends to be without 16.8V.
Remove the rainbow cable of BGM BOARD CN7303 :
Measure the voltage of Pin2 to the chassis to be without +12V
Measure the voltage of Pin 4 to the chassis to be without -12V
No output after the power is on, BGM BOARD red LED is not on or does not flash continuously
LINE OUTPUT CH1 ~ 4 -no output
MOH ( INPUT 4 ) – no input
The power consumption is correct after the power is on normally. (MA-725F is about 49 W;
MM-700F is about 6W)
LINE1~LINE4 input and speaker output are correct
But after input the priority 1.2 signal, the front panel green light is off, no PRIORITY output
Back panel switch to 70V/100V, no response
Back panel switch to HPF1 ~ 4, no response
Back panel switch to POWER REMOTE, no response
Defective status
15
NG position
STB PCB
BGM PCB
PRIORITY
PCB