110V 850W LED Microcomputer Electric Hot Plate Preheat Soldering Preheating Station Welder Hot Plate Rework Heater Lab

I purchased the hot plated for soldering rework use.The aluminum plate is plate is about 1/4 inch thick. By reflecting the light off of the surface at an angle one can see machining marks. It looks like the plate was flattened by a rather large fly cutter.When first turned on at 150C there is some burn-off from the plate which was probably the remaining cutting oil. I suggest doing the first turn on outside.At 150C, the hotplate overshot by about 15-20 degrees then fell back to 150C and stayed there.I used a thermocouple probe, to spot measure, over the plate and found 255F /- 5 degrees which is probably the error limts of the measurements. In short it looks pretty uniform. The reading of 255F converts to 124C but the thermocouple probe bead was just held against the plate so is probably giving a low reading compared to the actual aluminum temperature. The wire on the thermocouple also acts as a heat sink which also lowers the temperature reading.The paint is a power coat and is rather resident to wear; as I discovered while removing some paint for a ground connection.The manual warns to check the ground. I did and the ground measured ok. I removed the paint around the screw that grounds the plate assembly via the two sets of metal standoffs (see pictures). Then I added a spade lock washer under the screw (see picture).The chassis ground is provided by a screw that bites into an expanded/drilled (punched raised) place in the metal that allows the screw to get a bite into the metal. I removed the top bit of paint on the raised spot, so as to improve the grounding.The heater wires seem a bit small but do work. The red wires near the heaters have a fiber sheaf, covered with something that feels like a silicon coating.There are 3 places in the screw bank where the bare wire was just pushed in and tightened. Reading the picture from the right to left the screws are 1, 2 and 4. I added forked lugs onto the wires and soldered the wire to the lugs. This is probably not needed but makes me feel better about the connections.The fuse is in the 120vac plug receptacle and can be removed by using a small screw driver as a pry bar. The fuse is a 10 amp, fast blow. A picture shows the fuse holder setting near the top of the holder. The fuse holder slides into the 120 socket near the bottom. A rather nice design.The chassis is similar to a tear down shown on YouTube titled “ANSAI/BOZAN 946C – 800W Electronic SMD Hot Plate Teardown”. The temperature controller is not the same as in the video.The temperature controller is labeled as a RRKKCC (see pictures). There is a website listing that temperature controller as a “C100 K indexing relay transmission without alarm”. On Amazon if you search for REX-C100 you will find a number of models/clones that could be used as replacements if needed or wanted.The installed REX-C100 clone uses the internal relay to control the current. There appears to be a built in heatsink for the relay. I stopped the teardown at this point since there is no obvious way to open the unit without destroying it (see pictures).The RRKKCC is attached to the chassis by two sliding/ratcheting plastic holders. If one is careful and gently opens the holders a bit at a time on the top & bottom of the RRKKCC, then the unit can be removed from the holder. Note, on the bottom side I used a piece of metal strap to slightly separate the holder.My final conclusion is that the unit works better than expected and is built better than expected. The temperature controller has a heatsink and may eventually die (or not) but looks easy to replace with a different controller. The entire unit comes apart pretty easy and is a clever design. The ventilation holes probably have air going in through the sides and out through the top to provide cooling off of the temperature relay. The price is right.