The BL2000 does work with both audio and video systems, however slightly differently.  Have you tried the TV button?  Have you tired using a remote to select TV or DVD?

When you connected the BL2000 to the TV were both units unplugged from power?  Masterlink products should always be removed from power when making the master link connection, then powered up.

Hello Bill, thank you for your reply.

My BL2000 has a “Tape” button, and no TV button. I tried my beo4, it does not work.

Both devices have been plugged the power off.

the BL2000 works fine in my other set up - with Audio Master

You don't need an audio master.

Is the BL2000 in L.OPT 6?

To set this, put the system in standby.

Then, on the Beo4, press the POWER button and LIST together.  Then press LIST until OPTION is shown, press GO (centre button), and then press LIST to show L.OPT.  Then press 6.  The power light on the BL2000 may blink to show that it has been accepted.

I did it, the BL2000 acknowled the code with one blink. The result is the as follows:

TV on, and switch on BL2000 with the TV button on the remote. The BL2000 turns green, the relay clicks, and after app. 4 seconds the LED turns red und the relay clicks again.

if I push CD, Tape, or Radio on the device, same. LED green, relay clicks, and goes off after app. 4 seconds.
if I switch BL2000 on with the button on the left side, the LED turns green and remains green. But ni relay click.

by the way, I tried again a power off of the BV7 and BL2000 for 5 minutes. No change.

What other sources does the BV7-40 have?  Have you tried an analogue source such as DVD?

Not sure what you are expecting to hear from the BL2000 when you press CD, Tape or Radio?  These sources don't exist in the system if my understanding is correct.

Your understanding is correct. I just tried to describe the behavior . If i press TV, BL2000 act as like as tape, radio, so as if the source  (tv) does not exit. I have changed the cable, no difference. The Masterlink seems ok, because  if I press the off button for some time, the TV goes off.

What happens when you adjust the volume with the volume knob on the BL2000?

I once had a masterlink connection problem when using a masterlink cable for the first time in a beosound. When I removed the cable and checked the inside of the socket, there was some dust/lint inside from years of not having anything plugged in.

I could solve it.

in the monitor information (monitor service menu) I found “Option setting 6”. I tried to change it with the remote V.Opt 1 and 2, it did not change. I tried L.Opt for the Beovision, but he did not even acknowledge the setting.

so I "reset to default", and now the BL2000 is working.

I assume the TV was setup to a link TV, but how was that done?