Step 1:Connect the HDMI out from the V6 straight into the HDMI splitter box In (Note I tried a splitter cable but they didnt work as the signal needs to be boosted so plug it in with the lead that is supplied with it)
Step 2 Connect one side of the HDMI out to your TV and the other to the HDMI to RCA converter (you only need a small HDMI lead that you can buy anywhere) Note I tried a HDMI to RCA cable first but this didnt work as it appears the Converter needs to be powered, it comes with a power lead but only for a USB power point hence the need to buy a USB plug.
Step 3 Connect the RCA out to your Slingbox in the usual way.
That should be it.
I have mine up and running so hopefully it will work for you.
Let me know how you get on or if you need any more advice or information.
I have had a lot of experience using Sling devices and thought it might be useful to share some of it here.
I recommend that anyone wanting to connect either a Tivo or a V6 to a Slingbox, will get significantly better results by using an HDMI splitter connected to a component adapter rather than a composite one.
Component uses red, green and blue video connections (RGB) to provide what Slingmedia call analogue HD.
The recommended connection is to use an HDMI splitter with one HDMI going to a TV and the other to a component adapter then to the Slingbox. This is an example of the type I use:
Tivos can, of course, be connected directly to the composite inputs on a Slingbox using the scart connection and the supplied adapter, but the quality compares most unfavourably to component.
I have two Slingbox Pro HD models, one MI, 6 Slingcatchers, a Roku Stick and an Amazon Firestick as well as the Slingplayer App on various mobiles and tablets and use these devices to stream TV around my home in the UK and to my second home in Spain and also when travelling.
One Pro HD is connected to a Tivo by both component and composite (as a spare) and also to a Panasonic DVR by SVHS which both devices happen to support. For those who don't know, the Pro HD also has a built in Freeview tuner although this does not support HD. The other Pro HD is connected to a Humax Youview, again by both component and composite. The M1 is daisy chained with the Pro HD connected to the Tivo in case of failure (the Sling power supplies are notoriously unreliable and if one fails whilst I am away, which has happened several times, I can use the M1 as a back up).
The Roku and Firestick both have the Slingplayer App installed and are convenient to carry around. The Roku can connect to all Slingboxes but the Firestick can only connect to more recent models. However, it has the advantage that the supplied remote control can interface directly with the Slingbox without the need to use a mobile or tablet as an intermediate device to receive and cast the connection to a TV which is somewhat clunky.
Finally, just to confirm that all Slingbox production ceased last year and residual stocks will be sold until supplies are gone, so anyone thinking of going down this route doesn't have much time to buy a new device. After stocks are sold out the only way will be through the second hand market where eBay is probably the best option. Slingmedia have confirmed that they will continue to support users for the foreseeable future but who knows what this means?
After rage-quitting and ripping everything out, I saw your response and so thought I'd try again... I put it all back and now it WORKS! Very odd, but I guess I may have just had a loose cable or something.
I have attached a diagram of the setup as drawing it helped me to understand what was going on.
Thanks again for your help.
Also, I didn't know that about Slingbox being on the way out - let's hope they keep it going for as long as possible! Such a useful device.