IFR 500 Thumbwheel Issues

IDEC Switches

Unimax Switches

Most intermittent failures of these switches are the Unimax. If you are in the market for a IFR 500 , you will want to purchase a unit that has the IDEC switches if you have that option. Remember the IDEC switches are bigger in size and will rotate more easily. 

IFR Used 2 Vendors for the RF and Tone switches on the 500 and 500A Service Monitors. Unfortunately both of these vendors have stopped manufacturing these switches and refuse to make them no matter what the cost. About 15 yrs ago I tried to have the IDEC switches made. 

The Thumbwheel switch is the weak link for the IFR 500 service monitors. I have had some luck in rebuilding them but would prefer a better solution. A few years back I had another switch company make these switches and I never felt the quality was good enough to sell after the initial evaluation. There may be a few floating around in the world, and I spared no expense, new PC board but not the quality I was sold. Very disappointing to say the least. I also have made an LCD digital version with an MCU to fit in the thumbwheel slot. A overlay Lexan keypad was contracted out and it works very well. Now, I’m just a software hobbyist and I need to put a little more time in the memory part and storage of memory locations. Of course, I ran out of time and my repairs come first.