Mitsubishi Electric WD-57831, Service Manual, Page: 31 / 91

MODEL: WD-57831 / WD-65831 / WD-73831
Page 31
CableCARD
Cable providers send QAM64 and/or QAM256 through
the coax cable to the TV’s tuner. Once converted to IF it is
demodulated to an MPEG transport stream (TS). If a card is
present in the PCMCIA slot the TS will be passed to the card
and returned back to IC8506 and then finally sent to the Xilleon
processor. If there is no card present in the card slot and the
tuner is tuned to a QAM channel the TS will pass directly from
the POD interface IC directly to the Xilleon for processing.
Cable providers typically have both encrypted
and unencrypted channels. If the Xilleon receives an
encrypted TS it will ask the CableCARD to unscramble
the stream. The card will only unscramble the TS if it
receives the proper authorizations to do so. Those
authorizations are received via Out-of-Band data (OOB).
The OOB contains information about authorizations,
channel maps and more
.
OOB Tuner (TU-101 )
Main Tuner (TU-100)
(Cable/ATSC/NTSC)
PCMCIA
SLOT
(CableCARD)
Air
in
Cable
Ma
tr
ix
S
W
DEMODULATOR
IC1500
POD I/F
IC8506
XILLEON
IC8001
SIGNAL-PWB DM-PWB
Data Bus
TS &
Data
TS &
Data
TS &
Data
Data
Bus
To Engine
SYMPTOM POSSIBLE CAUSE(S) POSSIBLE RESOLUTIONS
1
No channel map appears when pressing
guide button (TVGuide disabled) Cable is not connected to ANT1 -or-
OOB data is not received correctly
1) Verify cable is connected to ANT1
2) Re-install/Replace CableCARD
3) Verify signal level and signal noise level
4) Contact Service Provider
5) Check TU101 for proper function/Replace Signal PWB
2
Channel map does not change after card
is installed. (still showing basic cable
map) CableCARD is not 'Initialized' within
the service providers system.
Contact service provider
3 Host ID screen does not appear
Signal and information not received by
TV
1) Verify cable is connected to ANT1
2) Re-install CableCARD
3) Replace CableCARD
4) Verify signal level and signal noise level
4
Error code received on screen. Error
codes are listed such as 161-x Communication between TV and card
is lost or disrupted
1) Pull card from TV and wait 5 minutes. Then reinstall the
card and verify it is initializing properly.
2) Press INPUT & FORMAT keys on the front panel.
3) Replace CableCARD with new card
4) Try 3rd CableCARD
5) Replace DM-PWB
5
Individual channel cannot be received.
(example HBOHD is no video and no
audio but other HBO channels are OK) The TV has no means to block
individual channels. Proper
authorization is not received.
Contact service provider
6
Certain tier of channels is not received.
(example: Premium channels or all HD
channels not received)
Authorizations to display scrambled
channels are sent via OOB data.
Contact service provider
7
Unable to tune to a channel. (example:
Pressing 1055 has no response and
stays on current channel) 1055 is not available in the channel
map. Channel map is sent via OOB
from the service provider.
Verify OOB is locked. If OOB is locked, verify channel
should be received. If not locked, troubleshoot for OOB
failure on SIGNAL PWB and/or with service provider.
8
When using SA card channels changing
automatically and random message
about upgrade in process. (Channels are
often like 10,000 to 50,000)
CableCARD firmware is out of date
and being upgraded by service
provider.
If this process continues more than 60 minutes, contact
the service provider for updated card
9
Periodically encrypted channels become
unavailable.
Card is hung Unplug card or AC or perform initialize
10
Only Analog channels can be viewed. All
digital/encrypted channels are
unavailable
Proper authorization is not received or
TV cannot display digital video
1st test for QAM clear channel (often network channels are
provided free), if no QAM clear channel is available
remove the card and memorize channels. Verify that a
digital channel can be viewed. If known digital channel
cannot be viewed suspect SIGNAL
11
ChannelView does not list program
content or channel call letters
This information is provided in the
form of OOB data tables and is sent at
the discretion of the service provider
Contact service provider