TMDS Signal
3.3V
TMDS
Example of waveform in check ① Example of waveform in check ②
Voltage scale：1.0V/div Voltage scale：1.0V/div
Time scale：20ms/div Time scale：1s/div
When the results of check item (30) are "22"
(Detection of DDC is OK.)
Check item(33). Checking register of the TMDS CLK detection status
register :
Send the following command from Termite.exe.
HDMI Rx/Tx
Send the command "i 0006 00FF 0001".
When the following value is returned, go to Yes.
HDMI In4 "22" HDMI In5 "11"
When the following value is returned, go to No.
HDMI In4 "20" HDMI In5 "10"
Check item(35). Checking the audio signal output :
Check the audio signal waveform at the following test point.
Is the waveform like the sample?
129/131/132/133/134/135/136pin
IC721
Check item (34). Checking the TMDS input waveform. :
Check the TMDS waveform at the following test point.
Is the waveform like the sample?
HDMI In4
80/81/83/84/86/87/89/90pin
HDMI In5
93/94/96/97/99/100/102/103pin
IC721
Checking the TMDS status register
Example
i 0006 00FF 0001
Check for a short circuit in the pattern of the
TMDS line of the HDMI Rx/Tx [IC721] from the
HDMI input terminal.
If there is no problem, the HDMI Rx/Tx [IC721] is
faulty. Replace with a new device.
HDMI Rx/Tx[IC721] is faulty.
Replace with a new device.
Recheck from check item (2).
If it does not work, replace the PCB.
The digital audio block is faulty.
Check the digital audio device.
Check "AUDIO" in troubleshooting.
If it does not work, replace the PCB.
HDMI Rx/Tx[IC721] is faulty.
Replace with a new device.
YES
YES NO
NO
NOYES
3.3V
The diagram shows an example of the wave-
form of pin 129. (I2S0 Data)
Waveform check points
- Crest value (3.3 V normally)
- Signal change
Check the waveform of each pin.
Voltage scale：1.0V/div
Time scale：20ms/div
92
Caution in
servicing
Electrical Mechanical Repair Information Updating
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