So I loved my TLM when i first got it, and used it a lot and then I got an ender 3 when they first came out and then a few more... Mainly because I was supporting them at the local school 3d printing lab I was helping with. So the TLM was ignored and eventually I moved it and it just sat in the corner. Anyways, FF to now and I wanted to print something and the enders were all busy so I fired up the TLM. It worked and I pledged to use it more. Thats when it took a crap. First the board didn't seem to work, it would warm up, home and print about 1/4 way though just stop. frozen LCD, motors locked and print stopped. So I pulled the board thinking that was the issue because back when I first got it, it fried the board and the TEVO Company back then replaced it but it was still within the 90 days but that was YEARS ago. So I decided to put in a Duet2Wifi I had. After much learning of how the Duet boards work, I eventually learned enough and could fix it and now know some basics about RRF etc. More feathers in the hat. The most frustrating part of that upgrade was the OLD style BLTOUCH. I could not get that to work right and finally tried a new (3.1) and it works great now. But then suddenly just as I was getting it to work, it started throwing heater faults. Well, back to the pile of parts i have and I found an E3d Volcano kit that I kept on hand for another clients and replaced that and then it was happy. So... I guess the heater cartridge was going out and throwing faults. I haven't put the old board to the test, but I would suspect that is the source of the old board having issues. Once I changed out the fake e3d hotend and thermistor with the genuine E3d products, everything is working hunky dory. Oh, I had to make a extended lead for the thermistor to because the genuine e3d cartridge style thermistor is a bit shorter than the little glass bead type that Tevo had on the knock-off. but no big deal. Now I just finished a nice vase and am working on a few other prints. Prints are looking good.
if you made it this far, I would say one more thing to think about such things, try a BTT SKR PRO V1.2. it doesn't have the cool built in wifi web interface like the Duet2wifi does but you can use it with a wifi addon or even just a RaspberryPI and Octoprint. And the SKR Pro V1.2 and RaspPi is still cheaper than if you bought a new Duet board. I just wanted to throw that out incase anyone is thinking about it and is on a budget.
I think the next mod I'd make to it is .9 stepper motors.
So, moral of the story is that even an old monster can be revived and taught new tricks. I know there was an Anti-Tevo sentiment when these first came to market and even the current Tevo/Homers suck when it comes to communication and I've heard stories of folks still waiting on their printers months later... So I can't recommend them but if You do get one, you know that it can be revived and still serve a useful life.