When OPERATION INDICATOR lamp flashes 0.5-second intervals or 1-time. Outdoor unit does not operate.

D How to check mis-wiring and serial signal error

Make them sure.

w1 Set the switch(SW2-2) on indoor electronic control P.C. board to MU or MUX type, when the outdoor unit is MU or MUX type.

If the setting is MUH or MXZ type, the unit does not work.

Start

w 2 Short circuit of JPG and JPS on the indoor electronic control P.C. board enables self-check to be displayed in 3 seconds.

Turn OFF the power supply(indoor/outdoor unit).

 

 

 

 

No

Set the switch(SW2-2) on the indoor electronic

 

 

Is the outdoor unit "MUH" type?

control P.C. board to MU or MUX type. w1

 

 

 

 

 

Yes

 

 

 

 

 

 

 

 

 

 

•Turn ON the power supply(indoor/outdoor unit).

 

 

 

 

Yes

 

 

 

 

 

 

 

 

 

 

 

•Press once EMERGENCY OPERATION switch.

 

Does the unit operate?

 

 

OK

 

 

 

•3 min. later, check the self-check result

 

 

 

 

 

 

 

 

 

No

 

 

 

 

displayed on OPERATION INDICATOR

 

 

 

 

 

 

 

 

 

 

 

 

 

lamp on indoor unit. w 2

 

 

Refer to the

 

 

 

 

 

 

 

 

 

 

 

"Instruction of

 

 

 

 

 

 

 

 

 

 

 

troubleshooting."

 

 

 

 

 

 

 

 

Serial signal error is indicated.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Yes

 

(0.5-sec. ON, 0.5-sec. OFF)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Is this mis-wiring, poor contact,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

or disconnection of wire?

 

 

 

 

 

 

 

 

No

1.Turn OFF the power supply(indoor/outdoor unit) and disconnect indoor and outdoor connecting wire on indoor side.

2.Short-circuit between indoor terminal block N and 3.

3.Turn ON the power supply(indoor unit) and press once EMERGENCY OPERATION switch.

Is there 20V DC between both ends of

R132 on indoor electronic control P.C. No board ?

( By tester, the stylus is between 0 ~ 20V. )

Yes

•Turn OFF the power supply(indoor unit). •Connect ON indoor and outdoor connecting wire.

Replace the indoor electronic control P.C. board.

Turn ON the power supply(outdoor unit).

Is there 230V AC between outdoor terminal

No

Check the outdoor power supply,

power supply cord and

block L-N(TB1)?

 

 

 

 

connection.

 

Yes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Is there 5V DC between J205 + –J101 - on the deicer P.C. board?

Yes

Turn ON the power supply(indoor unit).

No

Replace the deicer P.C. board.

During EMERGENCY OPERATION, is there 10V DC between both ends of R601?

(By tester, the stylus is between 5 ~10V)

Yes

No

Make the wiring between CN730

on the deicer P.C. board and

 

 

outdoor terminal block correct.

Replace the deicer P.C. board.

As for indoor unit MSC type, refer to service manual OB385 or OB393.

26

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Pioneer MUH-GA20VB, MUH-GA35VB, MUH-GA25VB service manual How to check mis-wiring and serial signal error
Page 25 Page 27

MUH-GA20VB, MUH-GA25VB, MUH-GA35VB specifications

The Pioneer MUH-GA25VB, MUH-GA35VB, and MUH-GA20VB are a trio of advanced multimedia head units designed to enhance the in-car experience with a blend of cutting-edge technology and user-friendly features. Each model offers a unique set of functionalities tailored to meet varying needs and preferences, while maintaining high standards in audio performance and connectivity.

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