Ungar 9911 soldering iron info?

mike

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Mar 10, 2016, 2:24:37 AM3/10/16

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I have an Ungar 9911 soldering iron handpiece
without the controller. Looks new.

I thought it would be trivial to build a temperature
controller.
I can make it hot. There is some PTC going on
as the current goes down as the iron heats up.

I expected some feedback.
The only other connector pins that have some
connectivity measure 497 ohms independently of
temperature. Can't use that for temperature monitoring.

Google has failed me.
Anybody know how these work?

N_Cook

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Mar 10, 2016, 7:22:55 AM3/10/16

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Any inductance with the 497R ? perhaps a small relay in the handle

Adrian Caspersz

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Mar 10, 2016, 8:42:20 AM3/10/16

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Probably it's a diode, and an auto-ranging DMM showing forward voltage
not resistance.

e.g.

http://www.tmatlantic.com/upload/aktakom/AM-1142_Diode_Test.jpg

Try reversing the test leads?

--
Adrian C

N_Cook

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Mar 10, 2016, 9:04:01 AM3/10/16

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Diode would make an excellent temp sensor, but you would have it right
at the duty end, for minimum time-lag, are there high-temperature diodes
? or a way to have a fast-response normal diode set in a
thermal-conductance scaled-down insulated sub-housing?

N_Cook

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Mar 10, 2016, 9:10:59 AM3/10/16

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Just got me thinking. Is there a soldering iron control system that uses
an IR pyro sensor , set well back in the handle , in sight of but can
monitor the heater block from afar?

Adrian Caspersz

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Mar 10, 2016, 9:13:38 AM3/10/16

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Yes, I started thinking that after posting. Who knows?

--
Adrian C

N_Cook

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Mar 10, 2016, 9:16:45 AM3/10/16

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The problem with soldering iron control is putting a temp sensor in the
heater block , if you can get away with simple heater and replaceable
tips only, keeps the costs down (and swapping-out universality up , for
hacker types).
Ah so no manufacturer would want that. Another thing to try out sometime
as a proving exercise.

Ralph Mowery

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Mar 10, 2016, 10:38:17 AM3/10/16

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"mike" <ham...@netzero.net> wrote in message
news:nbr79p$dis$1...@dont-email.me...

After a quick search here is some info I found. Seems that there is no
feedback for the iron.

On 3/25/2013 10:58 AM, Wild_Bill wrote:
> If you take the plug apart on the Ungar soldering iron cable (not fun),
> you'll see there is a mini variable resistor inside the plug.. no sensor
> used for the iron, in case I forgot to mention that.
>
> The variable resistor is used to set/match the iron temp to the chart
> supplied with the soldering station (so all the models have some
> consistency when set to lowest to highest temp settings).
>

N_Cook

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Mar 10, 2016, 12:18:12 PM3/10/16

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With an ordinary optical BPW21 photodiode with 18Meg resistor and DVM
over it, in a dark room, a good regular 10mV range bewtween on and off
of a magnastat iron with the window 1 inch from the barrel.
So could easily make a highly responsive temp-controlled iron with
simple heater and tips, what is drift like of photodiodes?

mike

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Mar 10, 2016, 12:24:49 PM3/10/16

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Thanks for all the thinking outside the box...
The calibration resistor seems like the most likely scenario.
There is some PTC. If I cool the tip, the current goes up somewhat.
Looks like all I need is a variable voltage source.
Where'd I put that box of old laptop power supplies???
It gets hot enough to melt solder on 12V, but haven't determined
whether it puts out enough heat to do real soldering work at 12V.

As for the IR sensor, yes, that's done.
I have some industrial grade hot air handpieces that have a sensor
outside the air path pointed at the heating element.
If you restrict the air flow, the element glows brighter for an instant,
then throttles back.

Ralph Mowery

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Mar 10, 2016, 12:45:45 PM3/10/16

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"mike" <ham...@netzero.net> wrote in message

news:nbsaf5$ja5$1...@dont-email.me...

> Thanks for all the thinking outside the box...
> The calibration resistor seems like the most likely scenario.
> There is some PTC. If I cool the tip, the current goes up somewhat.
> Looks like all I need is a variable voltage source.
> Where'd I put that box of old laptop power supplies???
> It gets hot enough to melt solder on 12V, but haven't determined
> whether it puts out enough heat to do real soldering work at 12V.
>
>

Most common conductors except carbon will increase the resistance when hot
and lower it when cold. When you cooled the tip , the resistance got lower
so the current went up. If designed correctly, most simple heaters are sort
of self regulating as to the temperature of the heating element provided the
voltage feeding it is constant.

I think I saw the voltage for the 9911 was 24 volts for the maximum designed
heat output.

Phil Allison

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Mar 10, 2016, 8:55:15 PM3/10/16

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Adrian Caspersz wrote:

>
> > Anybody know how these work?
>
> Probably it's a diode, and an auto-ranging DMM showing forward voltage
> not resistance.
>

** Diodes have a strong negative temperature co-efficient, about -2mV per C for silicon types. Plus cannot tolerate temps above 200C at all.

.... Phil

Phil Allison

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Mar 10, 2016, 9:12:01 PM3/10/16

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** It is possible to use the rise in the resistance of the heater element as a temp sensor - but not so simple in a unit that claims to use zero crossing switching for power control.

My Hakko FX888 ( 24V, 70W) has a heater that measures 3ohms at room temp rising to 9 ohms at soldering temp. A feedback winding on the heater unit measures 47 ohms at room temp rising to 140 ohms at soldering temp - this is what control the tip temp.

.... Phil

stra...@yahoo.com

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Mar 11, 2016, 1:13:09 AM3/11/16

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Check out a Metcal. The heater element IS the temperature sensor. I've been using one for 15 years and wouldn't have anything else.

G²

N_Cook

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Mar 11, 2016, 3:11:37 AM3/11/16

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I was aware of them , when they first came out. Just checked the price
of them and they will stay in the suppliers.
My magnastat came from the one-time Ferguson site at Gosport , with 1986
melted into the plastic by "Jane" on the production line.
I've worked out a simple way of making my own magnastat tips and if the
element failed, have a reasonable chance of making my own heater
(assuming by then replacement heaters will be unavailable).

N_Cook

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Mar 11, 2016, 3:15:24 AM3/11/16

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Just tried a 3mm LED sized, Telefunken S273P phototransistor on DVM-R
and showed regular follower 1M to 1.5M variation 1 inch from switching
magnastat iron barrel

mike

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Mar 11, 2016, 4:22:10 AM3/11/16

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I'd like to hear more about how you make the magnastat tips.

I'd have to agree about Metcal. Best I ever used.
I picked up a big handful of tips at a swapmeet.
If I ever find a free Metcal station to plug them into, I'm in business.
I thought about using a ham radio transmitter, but that seemed like
overkill.

N_Cook

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Mar 11, 2016, 4:38:19 AM3/11/16

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details on one of the tips (in other sense) files off
http://diverse.4mg.com/index.htm

stra...@yahoo.com

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Mar 11, 2016, 4:39:58 AM3/11/16

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New Metcals are definitely pricey but used ones can be had for a reasonable price. Power unit around $50, new wand is $100, add a $25 tip and you're still under $200. Over the years I've picked up over a dozen used ones for employers and friends. Two power units had failed and both were easily repairable. One Metcal is at work and it gets used 10-20 hours per week. My other Metcal is at home and is used much less but i don't like poor tools. I own 2 Weller magnastats but don't even pull them out of the garage any more.

G²