Huakko 936D and 907 clones - Thermocouple polarity - Page 1
Forum section: electronics / general

author: jimmc
author_rank: Frequent Contributor
timestamp: January 03, 2020, 10:03:05 pm
content: I have a Huakko 936D which came with a 907 Iron and works satisfactorily, I bought a couple of spare 907 Irons that do not work with it.Both the new an original irons use thermocouples but it turns out that the polarity is reversed between them.HuakkoNew 9071 Heater Heater2 Heater Heater3 GND GND4 Thermocouple +ve Thermocouple - ve5 Thermocouple - ve Thermocouple +veI am going to have to modify one or the other but I have not been able to find a definitive answer as to which is the correct / normal polarity, does anyone have this information?Jim

author: Shock
author_rank: Super Contributor
timestamp: January 04, 2020, 08:22:01 pm
content: Correct or normal? The genuine Hakko 936 schematic is on the web if you want to wire it like the original. There are a few different clone heaters, so you would have to measure the heater and thermocouple of each. This thread linked will give you an idea. However it's not worth wasting money on these irons building it into anything special.The best advice I could give you is if you want to sit near that performance level but be problem free at around $100 buy a Hakko FX-888D or if you want superior performance at around $200 get a Pace ADS200 which is the best bang for buck 120W station.https://www.eevblog.com/forum/reviews/genuine-vs-fake-hakko-936-ceramic-heater-a1321/msg236594/#msg236594

author: Acecool
author_rank: Regular Contributor
timestamp: January 05, 2020, 09:01:59 am
content: Is it like the 853D by Zeny?Big black box, soldering station and hot air. 4 screens. Power supply, solder temp, heat gun temp, volt-meter.It is true that the old tech these are built off of - the prices have dropped dramatically for reputable brands. Years ago I spent about $75 or close to that on my rework station and it is worth it. But Hakko has one for about $100 with a soldering iron, much better tips, etc.. No heat-gun but that isn't a huge deal.You can always pull the plug apart on the cheaper ones and look at the wires.. use a volt meter to check the ground pin then simply trace the other wires for your unit if you aren't sure. It could be they are slightly different for proprietary units.If you have the newer variant which has the better tip system - those are still pricey. ie: the ones which have the tips permanently attached to the ceramic heating element, with the thermocouple right in the tip for more accurate readings, etc...Anyways - the photo from the other thread shows the kind I have... The one with the the replaceable tips which has a bit of an air-gap, and hit or miss on quality, etc... You can get replacement handles for only a few dollars. I have 2 extras, never used.. I had some plans for them to build a vacuum desolderer using the original station with the original plug, and changing a few things but I never got around to it. I did make the heat-gun detachable though -- huge improvement and easy to do..

author: German_EE
author_rank: Super Contributor
timestamp: January 05, 2020, 07:37:36 pm
content: Wire up ONLY the thermocouple to the base station and note the temperature reading. Hold the thermocouple/heater assembly in your hand and watch the reading, if it goes up then you have the correct connections, if it goes down then reverse the wires.

author: Acecool
author_rank: Regular Contributor
timestamp: January 09, 2020, 02:37:21 pm
content: Use the volt-meter first... A sensor shouldn't have voltage pumped through - or that much, anyway. You could turn it on and put the voltmeter up to what you suspect to be the heater element... That should have a decent amount of voltage going through it. If you can put it under a load, then you should see a good amount of amps... Much higher than a sensor.The idea of hooking up the sensor first is a fantastic one. But you do need to be careful - some of these units detect whether or not something is plugged in. If nothing is plugged in, it will show an error.I do not know if it only looks for the thermocouple, the heater element, both, a ground, or what... Find the ground first - feed that through to your built-in multimeter ground input maybe.Also, if you pop the lid, you should be able to trace the wires from throughout.... It should be straight-forward to trace them. The heater element will probably go through circuits hooked up to heatsinks, coils, big square block with coils, etc... ie transformer, etc..If you can post a photo of what yours looks like - if it is similar enough to mine I can pop the hook to let you see what my pin-outs are.