Thanks for your response.

I think I can find a spare Panasonic remote control. But I assume that I should see a standby LED lit somewhere with the mains plug on.. or not?

Do you know something about the 3 bottom connections near the DVI socket?

Isn't there a RS232 socket in both BS3 and BV4?

This is used in the Beosystem 2 to send the control codes from the BS to the BV via serial cable.

Best regards
Ralf

It seems that your picture did not attach to your post.

You will not see an LED on the BeoVision 4. Keep in mind that the BV4 is a Panasonic screen "made pretty" by the aluminum frame. The aluminum frame will be covering any buttons or lights that might have been present. All of the control is done via the BeoSystem 3. The BeoSystem 3 connects to the BeoVision 4 by way of a DVI cable for video. There is another cable that connects from the BeoSystem 3 to the BeoVision 4 for control. The control is more than just for IR commands. It also has control over the picture settings. 

I think that you might have to select some settings on the BeoSystem 3 for it to detect the BeoVision for and to send out the correct video. You do this by pressing MENU, MENU, GO on the Beo4 (I believe I got the order correct.) while the BeoSystem 3 is connected to the BeoVision 4.

You might want to make sure that you have the BeoSystem 3 IR sensor connected to the correct input on the BeoSystem 3. Also, check that all of the wires are connected and intact within the IR Sensor itself. These wires are very fragile and it's extremely easy to pull them out or break them.

BTW,

There might be more inputs underneath the BeoVision 4. The BeoVision 4 has modular input "blades" that can be added for multiple inputs. Sometimes these vary from model to model. There is typically an extra input for a PC connection.

Good to know. I have uploaded a photo of the Beosystem connections. 

The strange thing is that I have removed the IR sensor cap on top of tv and checked for some voltage. There should be a small voltage typically 5v DC but everything seems dead. I also assume that the IR sensor should be detected even on standby, that's also why I am suspecting a faulty TV.

I think the supply voltage comes from the TV not from the Beosystem harness.

I believe that what you think is an IR sensor at the top of the screen is actually a picture calibration sensor. Do you have the external IR sensor that looks like a round hockey puck connected to the BeoSystem 3? It might be worthwhile for you to be a premium member on this site so you can get some of the more technical manuals. The BeoVision 4 screen is a rather unusual tv screen.

I stand corrected. According to the user guide on the Bang & Olufsen website, the BV4 does indeed have a built-in IR Sensor. 

Hi Beojeff ,

Tought so as I found an IR receiver along with other circuitry for picture calibration, but thanks for confiming.

So don't you think that I should have found some voltages there? I assume that the Panasonic panel alone should drive this circuit.

I have repaired thousands of TVs but this is my first "BIG" B&O device and am really surprised how active seems this forum, with prompt relevant replies.  I have previously successfully repaired a couple of CRT B&O without any help, so if I register for a Silver/Gold Premier Membership, do I get more technical help. I have service manual for TV but not for BeoSystem 3, would I find such service manuals then?

BTW, thanks for your patience :)

I have just purchased a reasonable Gold Membership.