Panasonic UF-5500 Service Manual page 131

11.2.3.2. INFO CODE=054
"INFO CODE=054" means that the synchronous signal out of the LSU cannot be detected.
The synchronous signal out of the LSU is detected by IC 300-G23pin (NHSYNC).
After the LCD indicates "INFO CODE=054 ", turn the power OFF/ON, then confirm
the waveform when the unit starts initial operation.
INFO CODE=054
Is CN500-1pin
Does CN500-5pin
Is CN500-3pin 'L' ?
Is the pulse
input into CN500-6,
Replace the LSU.
Note:
As for the "Pulse" waveform of the above flow chart, see the timing chart.
No
Check +5VD to
CN500-1 pin.
5V ?
Yes
No
Check R501.
turn 'L' ?
Yes
Replace IC300.
Check R518.
If there is no problem, replace IC300.
No
Yes
No
Check R502, R511, L500 and C506.
If there is no problem, replace IC300.
and 4pins?
Yes
NG
Replace R501
Yes
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UF-5500 / 4500