hakko T12 pinout?

[KL27x]

If anyone can tell me the pinout for the connections on the tip, I would be most appreciative. A link or a description? My searches don't return anything.

[stj]

found another reference for you m8.

[pigrew]

Based on quickly playing with a T12 and a multimeter, I'm thinking that it has an 8ohm heater in series with a thermocouple attached to between the two rings. The tip is ground.

[KL27x]

^thanks a bunch, guys.

I finally got my first T12 tip in the mail, yesterday, from a US seller off Amazon. It came in a plain faraday cage metallized bag with no "hakko" stamped all over it, like my T18 tips come, and the chrome plating doesn't look particularly smooth. I am assuming it is a fake. It was under a tenner.

I measure 8.3 ohms across the heater, which is surprising to me. I heard it was supposed to be 2ish ohms. Does not the heater increase in resistance as it heats up? Well I will have to do some testing on it, at some point. The 888D ceramic heater has 3.3ish ohms, for instance, when it is at room temp, but it reaches about 8.8 ohms at 350C. If the T12 tip does the same thing with the same coefficient, it is only running at 20W, lol.

Anyway, I hit my first hump in my 888 to 951 conversion. After switching the triac to the hot side, even when the triac is off I get a +-3V ripple out of it. I can't see getting a meaningful adc read of the TC out of this nonsense. I wonder if this is why sparkybg's controller rectifies the AC and switches unfiltered DC with MOSFET (and also uses zero detection to time the reads at 120Hz when available power is minimal).

I guess I shall have to see if I have a FET up to the task and then podge up a full wave rectifier. Pity, cuz I just finished populating and wiring up a dev board based on the Triac switching model. I guess I got the cart in front of the horse on this one.

[stj]

next-time buy from banggood.

my tips are all smooth like stainless-steel - i think they are.
they come in a sealed packet with HAKKO & stuff printed on them,
and they cost about £3 inc post.

[KL27x]

my tips are all smooth like stainless-steel - i think they are.

This one is shiny and smooth, but has a lot of dents in it. Under the microscope, at least. Talking about the chrome plated part, not the iron wettable surface.

 

they come in a sealed packet with HAKKO & stuff printed on them

All my T18 tips came like that, but I'm pretty sure two of them are fake. I think the fake "hakko" 900M and T18 packaging has just been around longer. I wonder if bangood isn't selling fakes, too. I don't think I've ever ordered from them, but the name doesn't inspire much confidence.

Sidenote: I don't have a handpiece, yet. But I rigged up a temporary handle. The T12 tip appears, fortunately, to be made to imperial sizes. It exactly fits a 7/32" drilled hole (which is also more or less 5.5mm), but then the ridges at the front are exactly 1/4". I don't know how much heat gets through the base of the tip assembly, but if I could figure out how to do the contacts, I think it would be possible to make a nice handpiece out of hardwood.

[stj]

https://www.banggood.com/search/t12.html
 

[pigrew]

Sidenote: I don't have a handpiece, yet. But I rigged up a temporary handle. The T12 tip appears, fortunately, to be made to imperial sizes. It exactly fits a 7/32" drilled hole (which is also more or less 5.5mm), but then the ridges at the front are exactly 1/4". I don't know how much heat gets through the base of the tip assembly, but if I could figure out how to do the contacts, I think it would be possible to make a nice handpiece out of hardwood.

I like the idea, though handles can be had fairly cheaply from China (less than US$20).

If making your own, keep in mind that you'll also need to install a temperature sensor (RTD or IC) in the handle so that cold junction compensation can be implemented. The thermometer should be placed as close to the contacts of the tip as possible. I think that the Hakko handles use a NTC RTD. The clones install a motion sensor in the handle, too, in order to implement a sleep function.

[KL27x]

I'm not sure these handpieces are supposed to have a cold junction sensor for compensation in the handle?

I have since received and examined some clone handpieces and boards. I am under the impression that the length of the T12 tip is such that the cold junction is not significantly affected by the heater. The handpieces have no components in the handle that I can see.

[pigrew]

Here are photos of the FM-2027 handle. The white wire goes to the RTD (using COM as the other terminal). It measures around 8.6k at room temperature. The DIN8 connector pin 1 is hot/TC (24V), 2 is tip (500 ohm to earth), 3 is COM, 5 is RTD, 6 is LED (powered from 5V with 1SS396 diode and 390 ohm in series (plus a bit of reverse voltage protection), shield is earth. One of the other pins might be used for barcode scanning... I'm not sure.

EDIT: If your handle temperature changes by 10 degrees (hot weather vs cold weather, or maybe your iron has been resting hot in its holder for a while), your thermocouple temperature measurement will be off by 10 degrees. Yes, you could put the compensation in the base unit, but it's a good idea to have it in the handle. Maybe even have the RTD in direct contact with the handle's COM contact.
 

[KL27x]

Interesting. So is this just a thermistor in the base of the handle? And the station reads this to determine the cold junction temp?

None of the 3 different clone handpieces I have opened have this. They have just 3 wires in the cable. T12 plus and minus and earth. In practice this appears to work perfectly good enough. I would think most electronics soldering is going to be done in a climate controlled environment, and the back of the tip does not seem to deviate in temp enough to matter (which this would be my main concern... thinking thermal runaway if the cj was heated by the heater!). And.... soldering irons are adjustable for a reason.

I'm curious. If you have a genuine Hakko FX950/51, have you noticed if the T12 is powered by AC/TRIAC or from DC/FET?

[pigrew]

Interesting. So is this just a thermistor in the base of the handle? And the station reads this to determine the cold junction temp?

Yes, my guess is that it's a 6.8k NTC, but I don't know the model (and I'd need to destroy the handle in order to find out).

None of the 3 different clone handpieces I have opened have this. They have just 3 wires in the cable. T12 plus and minus and earth. In practice this appears to work perfectly good enough. I would think most electronics soldering is going to be done in a climate controlled environment, and the back of the tip does not seem to deviate in temp enough to matter (which this would be my main concern... thinking thermal runaway if the cj was heated by the heater!). And.... soldering irons are adjustable for a reason.

I'm curious. If you have a genuine Hakko FX950/51, have you noticed if the T12 is powered by AC/TRIAC or from DC/FET?

Now you make me take it apart again?

You can see photos from the inside a FX-951 at in this other post. The switch FET is marked "J534 2YG 5J45". My guess is that it's a 2SJ534 p-channel switching MOSFET. There's also a big TO-220 BJT marked "C4549 5Y" on the board, but I'm not sure what it's for (voltage regulator?)

[M-Reimer]

I know that this topic is a bit dated, but maybe someone with an original T12 handle can tell me where this blue capacitor is connected between? Is this in parallel to the heater?

[Wsander12]

Just to let you know if you own the FM 2023 or the FM 2027 with this thermistor. And if that thermostat becomes damaged or stops working for any reason the hakko station will shut the tip off. I'm presuming it's doing that because it's thinking it's in thermal runaway and as a protection it shuts the tip off. It did that with my FM 2023 tweezers. The middle wire became detached from up inside the handle. And as a result that one side of the tweezers stopped working so it shut the tip off even though the tip was fine and in fully working order.