I had an old one given to me several years ago that did almost the same thing, but with a digital timer. I called the manufacture and they sold me a new timer for like $15 plus a few dollars for shipping, so you may try that. You can also just buy a new timer that will fit in the unit, if you want to do that.
Depending on upgrade cost, may want to consider one as mentioned above, I have "the timer" in 12v from Kevin (TxAg) on here and it is crazy good.
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