Hitachi 61HDX98B Service Manual page 79

WAVEFORMS FOR DM-1 TROUBLESHOOTING
After checking all the DC voltages between the DM-I and the Main chassis, investigate the Waveforms.
Check on Connector PMS2 Pin 3 (IP. Request) Check on Connector PMS2 Pin 5 (IP. TX)
vp-p = 4.937 V Freq = 49.61 Hz
DC = 4.72 Vdc
Check on Connector PMS2 Pin 4 (IP. Clock)
1
.oQv 50 .oy/
Vp-p = 4.781 V Frcq = 33.61 Hz DC Volts 4.72Vdc
Vp-p = 4.781 V Freq = 33.61 Hz DC = 4.72 Vdc
1
Vpwp = 4.012 V Freq = Varies DC = 0.069 Vdc
Waveform only available during Power On and Off
Check on Connector PMS2 Pin 6 (IP. RX)
Vp-p = 4.125 V Freq = 30.77 kHz
DC = Varies
WARNING!
If measuring from any PMZ Connector as Reference, other than Ground, make sure the Scope isn't grounded.
Damage to the DM-1 module will occur. Reference Pin example: Pin 2,4,6,8,10, & 12
WAVEFORMS FOR DM-1 VIDEO TROUBLESHOOTING
Check on Connector PMTl Pin 1 (Video NTSC)
2cq 20. oy/
Check on Connector PMS2 Pin 12 (NTSC V Cr)
Pm
,O.O~,
Vp-p = 950.0 mV Freq = 15.75 kHz DC = -0.24Vdc
Check on Connector PMS2 Pin I4 (NTSC Y)
Vp-p = 931.3 mV Freq = 15.74 kHz DC = -0.16Vd'do
Check on Connector PMS2 Pin 10 (NTSC U Cb)
Vp-p = 743.7 mV Freq = 15.74 kblz DC = 0.15Vdc
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