Sequre S99 Topic / Mod / Infos - Page 1
Forum section: electronics / general

author: ceut
author_rank: Regular Contributor
timestamp: December 09, 2024, 09:35:56 pm
content: Hello,I have received my S99, and I have 5.5Ohms between the tip and the USB-C shieldThe rear screw is also connected to the tip, so 5.5Ohms too between this screw and USB-C shield.We can sense the Vcc PWM on the tip.So completely different from the HT-140, where (I think) they have fixed this.I have the latest board 1.5 version into it (it is showing it in the menu)HW version: 1.5SW version: 1.08So I have to fix that.I have (and use) as my main Soldering Iron a TS-100 with IronOS inside, and properly grounded with a wire on the rear screw to earthI have made a little "mod" for my Sequre HT-140: this one is properly grounded too (USB-c shield to the 2 tips):=>The very simple mod I've done is to put the USB-C shield to my main earth with the USB-A negative plug of the SEQURE genuine 65W PSU - the USB-A and USB-C are sharing the same shield.@quispiam has done a mod here:https://www.eevblog.com/forum/blog/eevblog-1650-sequre-ht-140-smd-desoldering-tweezers-review/msg5710529/#msg5710529But I try to understand how this really works.It seems that SEQURE S99 uses the Thermocouple in series with the heater, and like the TS-100, when the power in the heater is cutted, the MCU reads the Thermocouple value(so they don't use the full potential of a C245 tip where both heater and thermocouple are separated)So I start a new topic for the SEQURE S99 soldering iron, after pointing the EarthGround problem of this iron(here is the link of my original post, but on the HT-140 topic:https://www.eevblog.com/forum/blog/eevblog-1650-sequre-ht-140-smd-desoldering-tweezers-review/msg5737327/#msg5737327)

author: ceut
author_rank: Regular Contributor
timestamp: December 11, 2024, 06:06:00 pm
content: With HW revision board 1.5, here are some finding in looking for the working of the C245 on this S99.The board 1.5 is different from the 1.4.It seems that there's only 2 "real" connexions going to the C245 tip: the center and the little right.The big part of the tip seems to go only to the ground screw: this part must be the common part of the Heater and Thermocouple.After cutting the trace to the amplifier, I have soldered a wire and checked alternately the screen to see what T° it shows.I have named 1,2,3 the three tabs of the C245-B1 clone I have had with my Sequre (like on the 1rst photo).Table of the reading of the Thermocouple(TC) value I have got from the S99 Oled screen:+ -TC 2 3 : 19°CTC 3 2 : 19°CTC 1 2 : 19°CTC 2 1 : 19°CTC 1 3 : 10°C ADC value (in the Calib menu) stays solid at "1" without movingTC 3 1 : 10°C ADC value (in the Calib menu) stays solid at "1" without movingThe mesured R value is (with a Fnirsi HRM-10 Internal Resistance Meter):+ - + -R 1 2 (or 2 1) : 5.32 OhmsR 1 3 (or 3 1) : 0.035 OhmsR 2 3 (or 3 2) : 5.34 OhmsWith my DMM on T° mode, and hotair gun set at 100°C on the tip:I find the (+) of the Thermocouple on pin 3, and the (-) is either 1, or 2.All that is strange, and not like some pinout I have found for C245 tipsI have to dig all that, don't know if anyone could help ?Edit: After drawing some draft on paper with all these data, I think I have found how the tip is connected to the boardBut again, I don't understand how the Thermocouple is read by the MCU because of the strange reading between 1 and 3 by the S99. Will check that later

author: ceut
author_rank: Regular Contributor
timestamp: December 12, 2024, 11:22:00 pm
content: It's me again, alone in my topicI think I have found a way to fix the temperature measurement problemIt is a multi-layer PCB, I have finally succeded with removing the trace on the PCB to isolate the tip2 layers of PCB to remove in each sideso 4 layers PCB ?I have also lost the link/trace between the ground screw and the end of tip, but no problem as all will be grounded (I hope so)Will post after if all is good...

author: ceut
author_rank: Regular Contributor
timestamp: December 15, 2024, 12:46:59 pm
content: I have finally succeeded to mod my S99 with keeping the correct reading of the thermocouple.After checking many things, I have seen that the ADC/OpAmp needs the Heater resistance value to get the Temperature reading correctly.So, here my final mod with a handmade schematic, simple to do with a 5.6Ohms SMD resistor (value of the heater tip) in series, but very difficult to put back in place as there is not much space to solder big copper wireAs the value of 5.6Ohms is always there, with this mod, no need to recalibrate with Tips of 2.5OhmsThis mod also allows the reading of the Thermocouple and powering the Heater individually - They are in series in the original Sequre design, so we can't read the Thermocouple while heating and "vice versa"-- Maybe great for faster and more precise heating of the Tip with an alternative firmware like RALIM/IronOS ?I have also made a Youtube video here, to show it with and why I have to make that[ End of this topic, hope sharing this will be useful for some of you who would like to mod their S99 too]

author: Sophie
author_rank: Newbie
timestamp: March 31, 2025, 12:08:05 pm
content: Thanks for this! I just noticed the temperature issue with some 2.5ohm tips myself, and also found that ironOs is working on support for the s99, so i cant see why this wouldnt be something that could be fixed in software, with a tip setting, and different calibration curve or something.https://github.com/Ralim/IronOS/pull/1920