Partial Answer Why so flaky?

Possible help:

1. Filament stops extruding randomly - Try seasoning the nozzle, using an oiler, replacing the nozzle with a new one (seasoned).
2. Sometimes the heat bed reports zero - Bad thermistor wiring, or a short. It is actually more dangerous if it always reports zero than if it reports too high, as there is nothing to stop the hotend from burning up.
3. Sometime the printer won't even turn on - Hard to say, may be a weak power supply or a loose mains wire going to the power supply. Just a couple of guesses.

 

1. season/run an oiler like @WheresWaldo pointed out above. That sounds just like micro-clogging.

2. Thermistors- if they show Zero it would mean unplugged or a broken wire (or the ramps board has an issue and thinks its unplugged). Max temp (just so you know) would mean shorted (two wires touching together causing the heated element to heat non stop).

3. Wont even turn on will need some more information. As in you flip the power switch and nothing happens? but if you do it repeatedly it will eventually turn on? Like Waldo said- check your wiring. Do it unplugged, dont hurt yourself, electricity is no joke. if everything appears in order I'd suggest getting a digital multimeter and checking the switch. Its likely failing and can be replaced fairly easily. If switch tests good, time to start looking at the powersupply. Most these power supplies have a green indicator light on them, flip the switch, does the light come on? No- switch or powersupply. Test switch- is switch good? Replace powersupply if all wiring is in place. Test switch- bad- replace switch first then move on to the next issue if there is one.

Luckily all parts are easily obtained and fairly cheap for the R1 series.

 

With the exception of the R1+ customized RAMPS board, but @Geof has a thread that shows you how to substitute in a standard RAMPS.

 

It was a typo, don't be pedantic. Of course I know the bed thermistor only results in the bed heating infinitely which can cause it to burn out or to draw power continuously resulting in a possible fire.

 

If it were my machine, and you have the same issue with multiple hotends, I would use an oiler. It will help with PLA and won't hurt the other filaments that don't need an oiler. If it is more than PLA then just replace the nozzle with something other than a cheap Chinese nozzle. Just to be honest I use cheap Chinese nozzles, as I assume a lot of people do, and I just toss them as the first hint of trouble. Also you do not mention what hotends your are speaking about, are they Hexagon? E3Dv6? or some clone?

A weak power supply could be the issue. It may have enough power to run but if it has been running for a while but when sitting and the capacitors drain it might not start up properly. Robo did not use the highest quality components on the R1 series. Most of the stuff is as inexpensive as their manufacturing contractor could supply. Things do go bad.

 

Or weak or worn-out heater core. Same behavior. $2-4 buys you a new one.

 

We are here to help

Yes, it can be a bear trying to sort out some of these issues. PLA and oilers/seasoning is common, but not everyone needs it.
Like @WheresWaldo mentioned if it is not just PLA, it is something else. The discount hotends are NOT a money saver. You might get lucky and they work, but too often they fail and now you are totally confused (because "Hey -- new hotend")

 

The hexagon is generally a good hotend, but it is not top-of-the-line. Others like the prometheus and E3D are better. It is not as simple as it used to be since there are now different styles of thermistors to deal with, but generally it is still fairly easy to swap out the hotend on the R1 series (the C2/R2 -- not so much).

Lastly, no -- I don't think you have bad electronics, not from what you have described so far.

 

Digital Multi Meter will sort out "questionable" items. if you have one lets break it out, if you don't have one, I strongly suggest getting one. Even cheap ones from Harbor freight will do for 3D Printing. Mine have saved me hours of headaches( and spare parts I didn't necessarily need, though spare parts are a great thing to have)

 

I wasn't offended, no worries. There are a few cheap options for the micro-clogging, already mentioned.

1. Oiler / seasoning (just like seasoning a cast iron skillet)
2. Replacement nozzle (you don't need to rush out and buy a genuine E3D nozzle)
3. Weak heater core

A RAMPS replacement board is cheap, especially on Amazon with PRIME. Don't buy cheap clones of hotends, as @mark tomlinson mentions, sometimes you get lucky and they work great, but most times they are less than what you pay for.

 

@Geof might have some good insight on the CR-10.

 

I've got one. In my opinion they are worth the entry price, but they are still cheap chinese printers, expect to replace fans and some other stuff and dont let it run unattended(warning for all printers from me to you ).

One thing I hate is the bed can get to 50/60C no real issues but much past that and its a struggle and crazy long. The CR10S from @Printed Solid is a much better bet IMO. He inspects them and its the upgraded with a runout sensor and two lead screws for Z instead of one. (I upgraded mine to have two Z lead screws- 100.00). So IMO its a PLA only machine without hotend upgrade, firmware upgrade and probably a bed heater upgrade. There are some other materials you can print on it for sure (PETG if you work at it but mind the max operating temp of the hotend and a few flavors of nylon- same warning as petg).

 

Really in that price range the CR10 is the only one I'd recommend. I typically steer clear of the cheaper chinese machines. I do 3D printing full time so I need reliable, and typically they are not. The CR10 so far has been ok and has a few thousand hours on it, but above complaints still apply. One day I'll get some time and upgrade it, but currently I put anything other than PLA on a different 12x12 machine I've got.

You may be money ahead getting the R1 going again (shouldn't be too much hassle once we start testing with you) and saving up a bit of cash to get the "step up" version if the build size is what your after. There is also nothing wrong with buying the cheaper CR10 and adding the lead screw later, the only thing you wont have that the CR10S has is the runout sensor and with some upgrading (main board) you can add that and upgrade the firmware. (I havent dont this yet, but is on my list when time allows). Feel free to DM me as well if you'd rather and we can talk directly or over the phone.

 

Possible. I would not normally expect that unless it had been changed and the firmware had the incorrect type, but anything is possible.