So not my first post here for a timeline of issues on my ender 3 pro so lemme give the runup of what has happened til this point.

I am in north america which is relevant to the issue.

-I was getting frequent thermal runaways and looking online seemed to tell me to replace my thermistor so I did.

-thermistor replacement didn't solve the problem. More specific details. I barely got myself to a goal temp of 215, then it dropped to around 200 for a couple minutes and then thermal runaway. I got 3 sets of recommendations: Mainboard is screwed, heat cartridge needs replacing, PSU needs replacing.

- Took a voltimeter to the power leads and saw that the power dropped to 19.5V the moment I started a nozzle preheat so figured that was the place to start. Ordered parts and looked up how to replace psu. Apparently for us the voltage needs to be set to 110. I noticed mine was set to 235. I found it! (I thought)

-I switched it to the lower voltage (listed 115. This is still my stock psu) and tried to print. I made my target temp and for a second it overshot it before coming down to normal. a few seconds into actively starting to print i got a spark! It is in the nozzle housing area but since my fan and cover was on I don't know what exactly in there went off. Screen goes blue for a second and power cycles. At that point I cut power because I was concerned.

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Before I was concerned but now I am really concerned to try anything without getting external help first. Lemme know if you need more details.

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After Spark Images:

https://imgur.com/a/rAhyGTc

-As far as I am aware there isn't visible damage on mobo or heater or thermistor?

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EDIT:

I just went and did the swap (since I had all 3 I swapped motherboard, thermistor, and heater cartridge to be safe) only for my motherboard's fan to break in a way i'd need a soldering iron to fix. Just my day. Looking online seemed to tell me it wouldn't explode so I did like 2 layers of a print anyway while keeping it open air and fanning it myself a little. No sparks or stops so fingers crossed thats enough. I need to either find a way to fix that fan or wait to get another tho for a proper test.