Interesting 936 to T12 (FX951 Integrated Tip) conversion

[nukie]

While surfing around the worlds factory outlet, I found this interesting circuit mass produced that enables use of existing 24V Hakko 936 transformer or any 12-24V  power supply, conversion for use of T12 tips. Have fun.

http://item.taobao.com/item.htm?spm=2013.1.0.138.agHenG&id=14545897965

[nukie]

Smaller still 

http://item.taobao.com/item.htm?spm=a1z10.5.w4002-711606001.11.hU0ut2&id=16080059650

[nukie]

Here's the screw neck for handle conversion if anyones interested.

http://item.taobao.com/item.htm?spm=a1z10.3.w17-8334311666.19.ywtdIk&id=19506236998&

[amyk]

If I'm reading the schematic correctly it's an oscillator whose duty cycle is controlled by the thermocouple voltage... surprisingly simple circuit.

[001]

Hey Hey! Anybody tried this analog controllers for T12?
Whether to proceed to the T12 instead 900/T18 tips?

[dannyf]

It is not a converter - it is a miniaturized T12 controller integrated into the handle. The addition of the diodes prevents reverse voltage damages.

Anybody tried this analog controllers for T12?

It is a proven design and many copies have been built. So yes, it will work.

it's an oscillator whose duty cycle is controlled by the thermocouple voltage

Depending on your definition of "oscillator".

If the thermalcoupler's output is too low, U1A's output goes low -> U1B's output goes high, turning on the heater -> for a period controlled by R4/C2. After that, the heater is turned off, the temperature detection phase begins again.

The diode on U1A does all the trick.

If the

[amyk]

Thanks for the explanation, it makes a lot of sense now. When the heater is on, the voltage across it is high enough to keep the U1A's output high. It senses the temperature while the heater is off.

[001]

It is theoretically good idea to use composite heater+tip…
But is it REALLY T12 best then 900M/T18 tips? Any practics?
Is it time to change 907/936 irons? 

P.S.: Some homemade AVR-based digital controller for T12 (schematics and firmware):
http://radiokot.ru/forum/viewtopic.php?f=2&t=101844

[dannyf]

It is theoretically good idea to use composite heater+tip…
But is it REALLY T12 best then 900M/T18 tips? Any practics?
Is it time to change 907/936 irons? 

Depending on what you mean by "best". T12 handles run much cooler - in fact, you can build a T12 handle out of a plastic pencil holder. Try that with a A1321 heater, . T12 is also much easier to replace.

However, the heater is far more expensive than A1321/22, and more fragile as well.

P.S.: Some homemade AVR-based digital controller for T12 (schematics and firmware):
http://radiokot.ru/forum/viewtopic.php?f=2&t=101844

Way to complicated. You would need 2 adc pins (one to read the heater and one to read the pot to set target temperature), 1 to turn / off the mosfet. So a 8dip chip would be sufficient - I built a few with PIC12F675.

[001]

The project to which I refer is long story of A1321 controller
This link is only adaptaition for T12 to save labor

[dannyf]

I have no idea which one/ones you are referring to but the Russian site as well as the link from the OP are for a 2-wire heater core (aka T12-like). The A1321 is a 4/3-wire core with a ptc sensor.

[001]

I have no idea which one/ones you are referring to but the Russian site as well as the link from the OP are for a 2-wire heater core (aka T12-like). The A1321 is a 4/3-wire core with a ptc sensor.

All right!
The previous epic threads are:
http://www.radiokot.ru/forum/viewtopic.php?f=25&t=2016
http://www.radiokot.ru/forum/viewtopic.php?t=8505


Interesting reverse-engineered Aoyue 2900 (T12 tips) with alternative firmware:
http://radio.aliot.com.ua/?p=945

[dannyf]

That's another complicated design.

[dannyf]

It is fairly easy to drive a T12 handle using a 936 station: you just need to wire a high-common voltage range differential amplifier to the handle. Many times, a high-side current sense amplifier will do (50 - 100x for example).

Driving a A1321 handle using a T12 controller can be done as well.

[Sjaak]

Way to complicated. You would need 2 adc pins (one to read the heater and one to read the pot to set target temperature), 1 to turn / off the mosfet. So a 8dip chip would be sufficient - I built a few with PIC12F675.

Could you provide a link to this project or give more info? I'm very interested in these tips as they seem to be fairy cheap on ebay.