From what you have tried it would most likely be a motherboard issue. I can't diagnose any further remotely, sorry.

Your options? That's up to you. The Series 1 is getting old and can do just standard definition and only record one program at a time. But then on balance you can still feed it external video from a Foxtel box (no external video input on a TiVoHD) and the old TiVo's are still repairable and have many years of life left yet if you can live with it's video limitations as mentioned above. They *are* slowly being replaced with people wanting more but then there are also still hundreds out there with people still very happy using them and I'm always happy to keep the hardware working as long as people still want them.

Then again if you only use your TiVo for free-to-air recording (ie not Foxtel) then the TiVoHD is a very nice piece of kit and a few hardware and software hacks are starting to emerge for it which make it even more attractive.