Thermistor shorted on hot end, RAMBo board fried?

[Tropicalsq744]

Hi guys,

So I haven't had much luck recently.. Was replacing my spoiled thermistor, soldered the legs to AWG22 and did the whole JST pins thing (quick disconnect setup). In my haste to get it up and running I left the soldered portion unshielded while trying to place the thermistor (with RTV) in place. I left the printer on, thinking that I could detect problems if the temps went def. It would've been ok had the wires behaved, but they did not, and the soldered portion touched the heating block, causing a spark and one side of the soldered portion to come undone.

After using yet another spare thermistor and restarting the printer, the hotend heats fine, steppers run and all, temps are showing fine, only thing is the heated bed (adjusting temp from LCD or mattercontrol) causes a shutdown right away. if you turned on the printer without being told, though, you wouldn't know something is wrong.

Do I have a dead RAMBo? Are there any quick fixes or do I need a new board?

[Mac The Knife]

Try disconnecting the bed wires at the Rambo. Does it still shut down when you turn on the bed?

[bvandiepenbos]

I don't think it is your Rambo board, it could simply be your power supply shutting down when heated bed starts drawing power.
The power supply SeeMeCNC supplies with the kits is barely adequate and low cost. They are known to sometimes crap out, or slowly getting more flaky over time. But sometimes they last for a long time, my first MAX still has OEM psu and has been working fine for 3+ years.

I would suggest you upgrade to a better power supply.
The total "Rated wattage" is not so important, what is the most critical is the amps it can output on the +12 volt.
For example, I have two psu setting here on my bench, both are 450 watt rated...
The Viotek from SeeMe is 22A on the +12 volt
The Silverstone ST45SF-G has 37A on the +12 volt

The Silverstone unit works awesome, but is a bit more money than others because it is small form factor and total modular connections.
You don't really need those things, I just like the neater plug in wiring and small size.
http://www.tigerdirect.com/applications ... CatId=1078

If you are printing PLA you could do without the heated bed by printing on blue painters tape.