There was never anything made that rivaled the EH75 combo unit in terms of overall functionality. If your unit has died, your best bet for getting the functionality back is to get it repaired. The way to do that is to send a private message to the forum user MICKINCT and describe your problem. He has repaired more then one of my units, and units for others here, all with positive results. A thread about him is here:
There are only three DVD recorders made for North America today, and they are all in the same family, and available at W*lmart. None of them have dual tuners, but they have digital tuners, and they work pretty well, unless your cable company has decided to scramble all of their channels, in which case, you would need their STB to record anything. The A/V output from the cable box goes to the A/V input on the recorder.
As good as the EH75 is, I found for my VHS to DVD dubbing project, they were not up to the task. I ended up getting the best results by using separate VHS and DVD components.
There is one more option to consider. The Panasonic DVD recorder models EH59 and EH69 are available from World-Import, B&H Photo Video, and a few other places. They have an interface almost identical to your EH75, and they have the same editing features. The only big catch is, the tuner in it is for PAL countries only, so it won't work in the US. If you are using a cable box, the A/V output from the box goes into the A/V input of the recorder and it works perfectly that way. There are a few minor considerations that I'm sure jjeff will bring up if you show any interest in getting one of those models. I use my EH59 quite a lot and I can assure you that it functions just like my EH75. It will even work with the same remote control if you prefer the EH57 one to the EH59/69 one. Of course, it won't do the VHS commands since it doesn't have a VHS on board deck, but the DVD recorder functions will work the same.