It’s a Somy Wega 50” from about 2003/4.What you may wish to consider instead is an HDMI to Component Video/Analogue Audio adapter. Search the web, there are lots of them. The adapter needs to be powered and needs to be able to accept the appropriate signal from the box.
The box may need to be set to output 1080i on the HDMI output as that's typically the limit for Component Video on TVs. You might even want to set the output to 720P because that's what the incoming signal is on Bell Fibe for HD channels. What is the exact make/model of the TV?
If it's a smaller TV (less than 40"), you might be better off purchasing a new TV. I've seen them for $200 or less.
I chatted with bell today. Totally useless. They basically told me to go get a tv with a hdmi input.Have you asked the Bell Installer or the Bell Customer Service agent if they can provide or ship you such cable?