New SSD installed, why won't boot-up recognize TM back-up disc?

2008 15" Macbook running OS 10.9.5. Time Machine backups are okay, on an Iomega eGo 1Tb external.

I installed a new SSD (Crucial), but when rebooting to the back-up drive I get the flashing question mark. Reinstalled the old hard drive and all is back to the old normal. Any suggestions? Could it have to do with the version of USB cable? But why would no problem with the external in combo with old drive? Should I put another Time Machine backup on a newer or different external, then try again installing the new drive? Should I try a different usb cable than the one supplied?

Thanks in advance.