J-head hotend

This morning I received an e-mail from the ebay store where I purchased the J-head hotend.  This was my very first Morgan purchase, shortly after Christmas.  They wanted to know whether I had received the hotend, and asked me to rate the purchase on ebay.

Of course, I HAD to go check the postbox before I responded (although I was there yesterday), and sure enough, the parcel was there. 

Back home this afternoon I wired the thermistor into the RAMPS connector, and connected the heater element to the appropriate connector.  I disabled the bed thermistor in the Marlin code and fired up Pronterface.

The J-head (sold as a MK V) is a clone from Hong Kong, judging by its 4 cooling fin slots as opposed to 5 (saw that on the internet somewhere) but it had a hollow set screw at the back holding the PTFE liner, and already wired up and Kapton taped together. The supplied wiring is just short of a meter.  No information on the thermistor that is mounted, so I selected thermistor '1' in the Marlin code.

Once Pronterface connected, I read the temperature, and it reported around 30 degrees C.  With the heat wave we have been experiencing lately, that was about right, so I selected 230 degrees C (ABS) from the drop-down and switched the heater on.  The LED on the RAMPS board lit up and I could feel the nozzle heating up immediately.

Pronterface can graph the temperature in real time and I saw it climb up to the target, once there, the LED switched off and started swithcing on occasionally.  Looks like bang-bang temperature control, as it flickers somewhat, but it tracked 230 degrees accurately.

With no way to confirm the temperature of the nozzle I pushed a piece of filament against the metal bottom of the J-head, and it melted as expected.  So far so good!  From the ammeter on my power supply it looks like approximately 3-4 Amps going into the heater element.