It seems like this topic is not very active anymore, but maybe the following does help someone:
I managed to connect a pair of tweezers called "Sunshine S1", sourced from Aliexpress. This instrument basically is a clone of a set of JBC Microtweezers, and uses the same tips.
For anyone who wants to try this as well, the wiring is as follows:
Black = outer shell White = A+ Green = A- Red = B+ Blue = B-
Just use the connecting scheme for JBC Microtweezers. I did not check whether there were diodes in the Sunshine S1 because I did not want to risk breaking something while trying to take it apart. But because everything seems to work ok, I assume no diodes are present.
They look fully identical in specs - for BZG03C36 - RthJA < 100 K/W Ptot 1250 mW - that looks ok, But: Mounted on epoxy-glass hard tissue, fig. 1a RthJA 150 K/W Mounted on epoxy-glass hard tissue, fig. 1b RthJA 125 K/W - look for the dimensions - How big have to be the pads to get less than 100 K/W and to reach at least 1250mW
I use SMBJ5365B, which is a DO214AA Package. It is a 5W rated part @75 degrees C / 3 W @100 degrees C. Not sure if it makes sense on this location, but it is reliable.
I think the mentioned effect might be from the noise generated by unisolder itself (fast heating and lack of enough output filtering in the test config sensing board), by the way, what tool did you use, T210? The new config is better, isn't it? Using 150k instead of 330k makes the filtering weaker (7 times better from test config), but with a faster reaction to states changing around 0.3s , corresponding to 0.7s for 330k
I use T245 and T210, the behavior is the same. The new config is better for sure. No clamping delay at startup, and immediate reaction to replacing the iron in the holder, also when changing tips. No noise seems to get through, the graph in the iron software looks clear.
I have the same effect with 330k resistors. It only happens, when the iron is in the holder from the get go. If the iron is outside of the holder while switching on my Unisolder and i put the iron in the holder while it heats up, it "clamps" almost immediately (maybe with a small delay around half a second).
Yes, exactly what I experienced as well. I expect you will notice the new configuration will solve this
Hi, Good news, after around one year of testing by all of you in different countries under different conditions the "Test Sch" is prooved to work - the results prove, that after the protection circuit passes only sporadic noise and even limited filtration does the job. Now is time for full filtration ( you Do Not need to change the Board), just to rotate two resistors, as is in the picture. Of course, if you want. Thank you for your trust.
I did not notice any interference with your design, but there is a significant other effect when I switch around the resistors: In the "old" configuration, when I would turn on the controller, the temperature would go up to almost the set temp before the holder would "clamp" the iron and reduce the temperature to the holder temp.
In the new configuration, the holder "clamps" the iron immediately.
By the way, I use 20K and 150K resistors instead of 20K and 330K so it might be part of the reason why in the old layout, this effect was observed.
So nearly a year to the day, I've finally got this thing programmed, MPLAB IPE reported programming was successful, but I saw nothing bootup on the sreen. I'm using a standalone SSD1309 based screen, onee of the DIYMore ones, and was curious if there is anything in the software or hardware I missed. I've verified that it uses 3.3V, and that the entire board is getting the correct power and wired correctly. Not sure what it could be, any advice?
I have a couple of those displays, and one of them refuses to display anything as well. You might have gotten a dud like me.
No, the resistors can stay the same as for LM2675M-3.3, however, you need additional 0.1uF capacitor between GND and VD on MAX5035, and also you have separate SGND on it. Both pins on LM2675 are "NC".
Also MAX5035's frequency of operation is 2 times lower, which means considerably larger inductance and output capacitance, so I am not sure if the substitution is at all possible.
I'll have a play with it. I am building my last pcb with some parts that I have still lying around, but I lack the LM2675, and it is completely unavailable unfortunately. I can get the MAX5035 and it's just to see if I can get this board to work. If not, so be it. I'll wait until the LM is available or take a gamble on Ali.
Would MAX5035AASA+ be a suitable replacement for LM2675M-3.3?
@sparkybg : Would I need to amend the resistor R3/R4? I am not really sure whether the pinout is compatible as the description is not the same in the datasheets. It looks like the power lines and on/off are on the same pins
@Doomedahab: Difference of upto 3-5 is normal. Usually it is around 2 or less. On my board it is less than 1.
I measured all my 4 boards now, and two boards show a difference of around one point, two other boards have an offset of around 5 points. On those two boards I will match the resistors a bit better.
But I still am waiting on a replacement multimeter because by now my cheap and old Vichy vc99 is completely useless, especially on resistance measurements. It drifted badly.
For what it's worth, there is no offset on my Unisolder when I measure both channels (R70 shorted with solder)
Maybe 1 point at most? it fluctuates between 999 and 1001 on channel A and maybe between 998 and 1000 on Channel B? At least it seems I see the 1000 a bit less often on channel B. It fluctuates very quickly so hard to say exactly. In any case, the channels are very close to identical
EDIT: The new C245 profile is spot on: Sn62Pb36Ag2 solder (179degrees melting point) starts to form a liquid film of solder on the tip at the 180 degrees setting, but cannot further melt any extra solder because of the thermal mass of the solder wire.
