Troubleshooting: Green screen

Symptom:

There is no picture or maybe a green screen following standby or when switching between source devices via a matrix. Most often this problem occurs once the TV goes to standby, and when brought out of standby to an ‘on’ state, it will not handshake properly and green screen instead of video appears.

Green screen flashes generally indicate a HDCP (Digital Content Protection) handshaking issue, or a HDMI hot plug detect issue between that particular source device and display.

1. Hot Plug Detect Issue

It is possible to determine whether or not it is a hot plug detect issue by physically unplugging the HDMI cable from the source device and re-inserting it. If video re-appears correctly after performing this action, it is likely a hot plug detect issue.

What is hot plug detect? (HPD)

The hot plug detect channel, which uses one pin, senses when you plug in or unplug a HDMI device, re-initializing the HDMI link if necessary. With HPD the sink indicates its presence to the source device. Hot plug detect is the first step in source device recognising a sink has been connected. The sink can toggle the hot plug detect signal to reset the HDMI connection.

Solution: The probable cause is that the source device is not asserting hot plug. Update the source device firmware, replace the source device for an alternative or put a “fix it” device between it and the display. (Contact customer services about “fix it” device options)

2. HDCP Issue

The probable cause is an HDCP authentication failure. The source devices is not processing the sink’s HDCP repeater bit. Sometimes the HDCP authentication link has been lost or was never able to be initiated at all.

Solutions: This issue can be down to a number of potential fault points, which all need to be investigated:

1. The twisted pair cable connection within the Cat5e/6 cable is not correctly terminated. Re-terminate the RJ45 connection, taking great care to ensure all connections are perfect, using the 568-B wiring diagram. (Applies to HDMI over Cat5 devices only)

2. The stored HDCP key on the system NVRAM memory is no longer valid for that source device. This can occur when a source device automatically updates its firmware without the owner necessarily knowing. When this occurs a system hard reset back to factory condition is recommended so that the memory can be cleared and the new correct HDCP stored the next time that the system is initialised.

3. If point 2 process does not solve the green screen issue, consult the source device manual for instructions on how to factory reset and firmware update. Ensure that the source device is fully updated and re-attempt point 2.

Further assistance

If green screen issues persist, Contact Customer Services. for further advanced diagnosis and troubleshooting.