Welcome to the SeeMeCNC Community

I put our Rostock Max V2 together over a year ago and am now experiencing some issues with the hot end. Everything was previously working just fine. I was just wondering if others out there had experienced similar issues.

The problem seems to be that at least one of the heating resistors is failing or completely gone. The hot end will try to reach the target temp, but doesn't seem able to get past ~200 C. I measured an approximate 10.5V voltage drop while the unit is heating across the resistors, which I assume is expected, and saw that the resistance was >7 ohms. (My multimeter is pretty crappy, the leads themselves will often measure ~3 ohms.) Since they are in parallel, the resistance should be around 3.5 ohms, right?

Based on this troubleshooting, I've already ordered new resistors (and spares) along with a new thermistor, just in case I wreck the current one while replacing the resistors. I guess I will also need new crimp connectors for the resistors. Any idea where the best place to get those would be, as in an actual store? Home Depot? Or local electrical supply?

Anyone else already done this and have some hints on a successful hot end repair?

Thanks in advance,

-rick

hi Rick,

You should take the opportunity to buy an all-metal hotend with heater cartridge. (HE280, PrometheusV2, E3D...)
For the crimp connectors, I don't know where you live but an electronic shop would be good.

Home depot has similar stuff, although it's almost always coated with plastic (Which you will have to remove). You might also try a dedicated electronics parts store, if you can find one. I would also try to buy new leads for the DMM there. Alternatively, buy either a Fluke 12E+ or a Fluke 15B+ (These are low cost, but feature rich multimeters, which are mainly limited by a lack of a CAT III 1KV rating, and the advanced features like True RMS, and PDM analysis that you see on the high end meters like the 87 series. An inaccurate multimeter is almost worse than no multimeter, as it gives you false confidence in a lot of cases.

The resistors don't ever seem to last very long. I eventually changed over to a heater cartridge. Then I upgraded to the HE280, If you don't want to do the upgrade I have my old hot end with the heater and good thermistor that I could mail you for free. If you want.

Dale

Gene made a video showing how to upgrade from resistors to a heater cartridge.
The bonus of watching his video is that whenever you read his comments in the forum, it will be with his voice in your head, not Yosemite Sam's.

https://youtu.be/xvXKt3xDt4E

I hear Yosemite Sam's voice whenever I see Gene speaking ...

Watch it, ya varmint!

g.