Mini TS100 soldering iron and current leakage

[wraper]

BTW I don't see claimed resistor on the schematic on it's front panel.

[stj]

that's just a sketch - post a photo of the base pcb.

[wraper]

that's just a sketch - post a photo of the base pcb.

Whaat? Burden of proof is on the claiming side (you claimed there is a resistor). Where should I get that outdated station in the first place, LOL? Have you even measured a resistance between the earth connection and the tip?

[stj]

yes, i did.
it had a resistor and rifa capacitor in parallel FYI.

still, it's history now - those are on my parts shelf with no electronics in them.
i was thinking of fitting a digital controller and ssr in them to use a newer iron assembly.

[KL27x]

@stj thx for the link. That helps. If im reading it right, there are only 3 connections on the cartridge, then. And the ts100 only uses 2 or them, no connection the to tip/sheath. So no hidden metal contact on the very back end of the cartridge?

[stj]

i think the ts100 does link the shaft of the cartridge to the earth screw and probably the input-jack.

btw, if your going to build a controller then you may as well build that one - it's the simplest i'v seen.
you can skip the gyro chip to make it even simpler.

[stj]

yes, lower-right of the schem.
j1 coupled to main ground via c26.

interesting. it wont pass dc, so no accidental discharging of big caps while soldering!! 

[KL27x]

Well i am not much good at this, but it looks like A and B are connections to either end of what would be the heater. If u look at the cartridge, u will see two ring contacts at the end away from the working tip. I assume these are A and B. And the rest of the cartridge metallic surface that includes the tip wouod be what should be earthed in an ESD safe iron according to IPCS or however u spell/acronym?

J1 at the bottom right shows a capacitor btn PGND and B. Which i am confused because B doesnt seem to be the tip, and capacitor wouldnt earth it even if pgnd was earthed.

[KL27x]

So my understanding is perhaps not full, here. I might have to shelve my controller dev until my T12 handpiece and tips get here.

The way I am guessing is that power is applied through A and B ring contacts, then cut, then a TC output of uV can be measured between A and B. But this implies that you can send several amps through the TC without damaging it, and I don't even know if that is possible. I don't know what the voltage drop and resistance of a TC is nor if you can do that without damaging it. In theory it's just two different metals welded together, so it seems like it should be possible to just use it as a conductor when not reading it.

A > heater wire > TC > B           

If my idea works, my Hakko 888 will be able to drive a T12 tip with up to 17% more power than an actual Hakko 951. And 70% more power than a DC laptop supply clone at nominal 20VDC max (without even including the pauses for reads needed in the DC version).

[stj]

o.k. i was a bit wrong.
the cartridge is earthed, the wrist-strap is decoupled through a cap.

your operational theory is right, the thermocouple is in series.
you power the element, then cut the power & read the voltage on the same pins.
then if it's under the set temp - power it up again.

this is the place it all comes from.
http://minidso.com/forum.php?mod=forumdisplay&fid=67

[KL27x]

Awesome, thanks!

I love your WS801 chassis, BTW. Should be able to make a nice bit of kit with it. I was considering buying an old Hakko on eBay to use for something similar. But it will be so much easier to hack an 888, if I manage to get it right. I plan to use the existing 888 interface and display for setting the temp, and my micro will just figure out where the 888 is set at by spoofing the 888's ADC and figuring out where it it trying to turn on the heater. Of course with a flip of a switch, it will be a regular 888.

[stj]

not WS, DS - it still has a big pump in it! 

[stj]

I plan to use the existing 888 interface and display for setting the temp,

i wouldnt,
scrap the electronics and start fresh.
the 888d's weak point is the interface.
and maybe use something like this!!
http://www.ebay.co.uk/itm/0-95-Inch-SPI-OLED-Display-Module-Full-Color-65K-Color-SSD1331-7-Pin-For-Arduin-/292115525887

[KL27x]

^true, the 888 interface is lamo. A better interface is phase 2, cuz that is a boring job.

What the 888 has going for it is a 26V torque beast hemi engine stuffed into the smallest box possible, comes with a really nice handpiece in itself, and Fry's likes to give them away for pennies every 4 months. I picked up a couple at the last sale, and first order of business is to unleash the beast.

[shinji2009]

hi.  can anybody please  tell what resistance must be from rings (contacts) of a tip to its body? i got two tips for ts-100 today and one shows megaohms and other gust 100 ohms so i wonder if one of them faulty and maybe i shouldn't use it.

[Gyro]

Hi,

The only continuity you should normally see is between the two ring contacts. The one with continuity between the rings and the body sounds faulty / dodgy (I'm not sure if anyone makes fake TS100 tips as it is a limited market).

Personally, I wouldn't use it and would contact the supplier.


P.S. The resistance of insulation always gets worse with temperature, so if it is measuring 100R at room temperature then it could be considerably worse at soldering temperature.