What to do with Old and Used Dehydrators
Many people buy used dehydrators at the flea market or yard sales. Usually, these are going to be really old and discontinued, and missing their original instruction manuals or recipe booklets.
Maybe the most common model that's missing instructions is the Mr. Coffee food dehydrator. The company is well-known for their coffee and tea appliances, but also made food dryers at one time. You can still find these, typically missing the manual, online at eBay and Craigslist, and thrift shops and the like.
The Magic Chef dehydrator is an older model that's still popular but no longer produced. Like many older, stackable dehydrators, tray rotation is necessary for recipes that require a long drying time.
Another discontinued dehydrator is the Bee Beyer. This was made in the late 1970s and early 1980s, and it's hard to find any information on it now. A reader recently emailed to ask about it. The best I could do was point her towards the Bee Beyer book, Food Drying at Home the Natural Way. It's out of print, but you can sometimes find a used copy online or at the library.
Check the Temperature
What I recommend doing is get a food thermometer and measure the temperature of the dehydrator at each level, since the they degrade over time and could be inaccurate.
All dehydrators are pretty similar, so the important thing to worry about is the internal temperature. Once you know that, make new labels.
Then, using any old dehydrator book or manual, test a few recipes. Over time, you'll learn to make adjustments to suit your specific dehydrator. Once you make a few batches of jerky or fruit, you'll know how much to increase or decrease the drying times for various recipes.