Philips DV29 service manual Comms and Final video output stage

Comms and Final video output stage

The signals from the main board travel up to the Comms board on connector CON902.

The Video signals simply travel via an A-C coupling net before exiting the player via the RCA-phono sockets at locations SKT902 and SKT903.

The RS232 interface is on 9 way “D” type CON900, with IC900 providing the level translation and static protection between the RS232 levels and the 3.3V CMOS levels required by the VADDIS V, CON900 also supplies a +5V Status level when ever the unit is not in standby this generated from a buffered version of the AV_ENABLE signal as used within the SCART output stage (0V in standby).

We have two remote input bus’s on this board, the first can be seen to arrive at SK901 on a 3.5mm mono jack signal received should be a 36Khz modulated RC5 signal, the RC5 data then travels to the front panel and is fed to IR led that is sited just behind the front panel IR Sensor, we use the sensor to demodulate the and opto-isolate the signal due to the fact that the signal is floating up from ground.

The 3.5mm socket at location SKT900 is used to receive un-modulated RC5 the 0V representing a space (equivalent to no-infra-red carrier), this input is effectively wire-Ord with the front panel IR receiver on IRRCV these take the form of a 5V/0V RC5 signal, with 5V representing a mark (equivalent to a burst of 36Khz carrier on infrared) and 0V representing a mark (space), the signal is simply inverted and wire-ord to the display board Infra-red led via TR900.