Question electrictronic gurus tattle tail monitor

Anyone know if it's possible to rebuild the Tattle Tail monitors yourself? Are they made up of relays or just what? I saw a rebuilt one on ebay for over $400 and for a combine I want to sell (L2) I just don't want to put money in that I will not get back. I already have lots invested in it with lots of new parts so that ship has sailed too far. I want the monitors to work though. The monitor with the beeper started to stay on at a constant tone the other day so I unplugged it. Shaft monitors have never worked at all and I've been through the wiring pretty good. If I keep the combine as a backup for a year or two I'd want them working anyhow and when I sell it I really want everything to work. TIA

Ag Express could probably fix it. I've taken planter monitors there before to repair. $125 to test, I'm not sure about repair costs.

Dad dealt with AGTRONIX out of Indiana to rebuild the digital tach on the F2 several years ago. We just unplugged the TT on our machine,none of the sensors worked and the alarm was less than pleasant, as I'm sure you know.

I've used and would recommend Agtronix in Indiana as well. I sent them a monitor to be repaired and modified. I don't hear high pitched sounds so was unable to hear when the alarm sounded, and the visual alarm is located too high for me to see it quickly if something trips it. So I had them set it up so I could mount a remote LED warning light on the steering column, easily in my eyesight as I'm watching the header. No more taking my eyes off the crop to look up at the monitor.

find the wiring diagram - put a VOM in the plug where you unplugged the shaft monitor find the ground then probe the other wires - you should read voltage on all the shaft wires with the machine running. IF not - it is not the monitor. Also all the old AC dealers have old monitor testors….