852D close soldering station heating element replacement issue

[GraphicMan]

Hello guys
I have got the A1321 heating element, i think there was a mistake in the listing on aliexpress as it states it is compatible with my soldering station but the problem is that i found it is not, the original and burnt heater have a thermocouple sensor (polarity matters) and the new one have a themistor sensor (resistance output, no polarity) the heater is compatible, the sensor is not
i have seen a video where someone did use it though as a replacement after adding a resistor on perhaps one of the inside pcb's of the station, i would like to make sure if that is possible (i wish i can make this mod to make it work)
attached are the pics for the old heating element before desoldering, as well as the new heating element
is there anyone can guide me through ?
thanks

[harp]

I am interesting... what is resistance of original sensor vs new one?
What happens when a new part is installed—how does it behave?

[GraphicMan]

I am interesting... what is resistance of original sensor vs new one?
What happens when a new part is installed—how does it behave?

I have not made that mod, here is the link
https://www.youtube.com/watch?v=pG0xtk9URAI
but i am not sure, that is why i am asking perhaps my soldering station is also different than his
I dont understand how adding a resistor can make such a conversion! I wish someone here can enlighten us

[harp]

I dont understand how adding a resistor can make such a conversion

A thermocouple sensor is made of two wires of different materials welded together at the tip. When the tip is heated, a small voltage is generated at the wire ends due to the potential difference between the materials used. This voltage is then amplified and processed.

With a thermistor, a special material is used that changes its resistance depending on temperature (and it always has a significant resistance), but it does not generate voltage. The video describes a way to obtain the desired voltage at the sensor (required by the controller) by using a voltage divider made of two resistors - one is the sensor itself, and the other must be added.

With a thermocouple sensor, the resistance is very low; it is simply a bare wire made of two different materials, and its resistance does not change significantly when heated.

I have 852D+ and sensor has 52 ohm on one side of connector, heater about 4 ohm at other side, and the middle pins seems shorted (or it is thermocouple sensor)

[GraphicMan]

yes i understand how both work, the question is , where did he get the initial voltage to begin with ?
if i open the unit can you help me out make it?

[harp]

where did he get the initial voltage to begin with

Maybe he measure value from original element... while power on. Or experimental, try and error...

Many people may have the desire to help, but in reality, you are on your own — do not attempt a repair until you fully understand what you are doing and how you are going to achieve it.”

[Agent24]

I had the same problem when replacing a heater like this.
There are several and not all are the same.
But most sellers don't know the difference.

What should work for you is the A1322 like this https://www.ebay.com/itm/206178916590
I think that is the style I got for mine. (Duratech Hakko 936 Clone)

Although the shape of the element base for yours looks more like this one: https://www.ebay.com/itm/182138169856

I wouldn't bother trying to adapt the different element, it will be a right pain and I don't think the heater will fit in your handle anyway as the wiring is too thick.
The correct heater is cheap enough.

[GraphicMan]

I had the same problem when replacing a heater like this.
There are several and not all are the same.
But most sellers don't know the difference.

What should work for you is the A1322 like this https://www.ebay.com/itm/206178916590
I think that is the style I got for mine. (Duratech Hakko 936 Clone)

Although the shape of the element base for yours looks more like this one: https://www.ebay.com/itm/182138169856

I wouldn't bother trying to adapt the different element, it will be a right pain and I don't think the heater will fit in your handle anyway as the wiring is too thick.
The correct heater is cheap enough.

i agree about the base end shape style, but i think it is not a problem because i have that from the original one, the soldering iron was barely used and i always use it at a very very low temps compared to what it can do, so i am assuming these cheap heating elements are already poorly made and i assume the replacements will be identical! but on the other hand the A1321 seems like proper ones and far superior to them, i wish i can made the mod and that it is not very difficult and durable, i want to give it a shot specially if it is reversible , i dont think that the wire are a problem it seems to fit

[Agent24]

Well the one I used has been working for years and even the original was still working, just the ceramic core was cracked so I replaced it as preventative maintenance. Sounds like you got unlucky with yours maybe.

[GraphicMan]

Well the one I used has been working for years and even the original was still working, just the ceramic core was cracked so I replaced it as preventative maintenance. Sounds like you got unlucky with yours maybe.

very possibly, can you share a link for the station that you have?

[Agent24]

very possibly, can you share a link for the station that you have?

Sorry, no, it's not made anymore. It's a Hakko 936 clone branded for a local electronics chain.

[stj]

cant you just swap the sensors over?

[GraphicMan]

cant you just swap the sensors over?

it is not available here, consider it a challenge/adventure
also i got 5 of them, so it will be nice if i can use them for the future, also these newer ones heat up much faster and suppose to be of a much higher quality

[stj]

i mean use the original sensor from the broken heater in the new heater

[GraphicMan]

i mean use the original sensor from the broken heater in the new heater

oh sorry i missunderstood you, yes i have been thinking a LOT about that, the sensor and i think they are all the same are built inside the heater, it is a ceramic thin rod with 3 tiny holes! 2 holes for the sensor leads and the third one is for one of the heating coil (the start of it) then the coil is wrapped around that ceramic rod, then another ceramic tube is over covering all that, now i have the old sensor yes with its rod, i did try it as a test after sticking it to the new heater and soldering all the leads to the pcb, that worked fine as expected, new heater to the board with old sensor, new sensor is not wired, but the problem is that there is no room for that ceramic rod that have the sensor, and if i break the ceramic rod it will not be possible to use the sensor because its leads will short from the steel housing as well as the tip tube, it is possible to wrap the old sensor with its rod outside the top but even with that i need to drill a hole to pass its leads to the pcb, i think but i am not sure that the best method is to use the new sensor but i have no idea about the amount of work needed to modify the station for that, i need help with that

[stj]

i would start by drawing a schematic of the sensor circuit.
then compare it to some other schematics.

[Agent24]

Sorry, no, it's not made anymore. It's a Hakko 936 clone branded for a local electronics chain.

Here's the description of that iron from the Jaycar 2008 catalogue CD-ROM.
It also claims to be a ceramic heater, but it's not, the cracked heater I have clearly has a spiral-wound wire heater inside.

I still use that station for a lot of basic work but it's not the most powerful.
I also built myself a Hakko T12 style station from an open source design.

[GraphicMan]

Here's the description of that iron from the Jaycar 2008 catalogue CD-ROM.
It also claims to be a ceramic heater, but it's not, the cracked heater I have clearly has a spiral-wound wire heater inside.

I still use that station for a lot of basic work but it's not the most powerful.
I also built myself a Hakko T12 style station from an open source design.

thanks a lot for the share , btw is there a way to know the real type of the heating element without cracking it?

[Agent24]

thanks a lot for the share , btw is there a way to know the real type of the heating element without cracking it?

I think you can tell by looking at it, from what I gather (but I may be wrong!) the true ceramic ones seem to have a vague outline of two distinct darker areas inside the heater core, while this is not visible on the other type, it's all just solid white. At least the comparison between my original heater and the incorrect (for me) A1321 heater shows this difference.

See the attached photo, you can see the different dark areas.

[stj]

i found this in my document-stash!

(this is why you save everything you see!!!)