HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron driver

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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby arhi » Fri Sep 02, 2011 5:08 pm

I got this from [url=http://dics.voicecontrol.ro/tutorials/mc34063/]here[/here] and it still don't work ...

I did try to use same 220uH L (as it states Lmin so should not mind if it gets bit more?) and C0 I used 20uF ..

After load goes over 50mA output voltage goes to few hundred mV ...

I'm waiting for the expert :D

btw, not sure what the actual Vin is ..

24VAC is a sine so 24*0.7 = 16.8, rectified is *1.41=23.88 but there's a voltage drop on the rectifier .. 1.1V as 1n4007 is used .. so 22.7V ?

So maybe it should be 24VDC +- 10% (21.6VDC - 26.4VDC) ?
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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby sqkybeaver » Fri Sep 02, 2011 5:27 pm

you may need higher inductance because of the large diffrence of input vs output voltage.
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I am doing something seriously wrong

Postby arhi » Fri Sep 02, 2011 6:21 pm

something is seriously wrong here ... here's the calc from http://dics.voicecontrol.ro/tutorials/m ... culate.php and it looks ok with datasheet (I recalculated all manually) ... I made the stuff on a actual pcb (strip board) as I assumed maybe solderless proto had some issues ... Still identical results ?! 0-50mA works ok, over 50mA kaboooom drops down to below 500mV ..

I'm using
for R2 3k3+300R
for Ct I'm using 680pF||680pF (ceramic)
for C0 1000uF (it only affects ripple)
for L I'm using 220uH


Why the hack this ain't working for more then 50mA when the calculation is for 300mA ... what am I doing wrong ?!
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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby arhi » Fri Sep 02, 2011 6:45 pm

sqkybeaver wrote:you may need higher inductance because of the large diffrence of input vs output voltage.


I don't have a problem to increase inductance, but I'm using the values from calculator according to datasheet :( ... (I did mention I do not know how this works right?) ...

if you have any ideas - please let me know .. I do not have many inductors here to test with (only 22000 uH, 220uH, 1uH - 10pcs each) but I could make some adding this in series and parallel ... just hit me with something to test and I'll get on to it immediately :) I just have zero ideas attm
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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby arhi » Fri Sep 02, 2011 6:51 pm

if it matters, the 220 and 1uH are in pack that looks like resistor - no idea what the current rating is and those 22000 are http://nl.mouser.com/ProductDetail/Fast ... FZWw%3d%3d (Maximum DC Current: 60 mA )
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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby Folknology » Fri Sep 02, 2011 7:02 pm

If you have the chip in a dill socket remove it and remove supply connection (Strip board version) and measure the resistance between pins 6 & 7 to make sure it's 0.5 ohms and not 3 ohms. Obvious check are the sense resistors are the correct value, for instance 1 ohm and not 10 ohms for example.

Your inductor needs to be about twice the max rated current by the way, you should also choose one with a low resistance normally a power inductor.

The latest values you use are better than the previous as those were incorrect (ct = 75pF is bad, operates at more than twice the rated frequency of the device!).

regards
Al
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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby arhi » Fri Sep 02, 2011 7:08 pm

I replaced that 220uH (that pdf shown) with 22mH (so 100 times more) and now I can draw mine 250mA while voltage drops only to 4.8V .. it's not perfect but it kinda works. What's the problem - the 22mH gets HOT and after few seconds I have to shut everything down as I'm afraid inductor is going to burn out.

If anyone has any ideas - shoot :) .... I wanted to use this switching DCDC because I assume it will be small and will fit on board and allow everything to be powered from 24VAC but I assume I need higher current rated inductor for this to work (probably inductor fails after it gets hot and that's why the whole thing fails) and to have inductor to not heat at 250mA it probably need to be rated 0.5A and that is going to be BIG .. ... damn .. there goes that idea ..
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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby Folknology » Fri Sep 02, 2011 7:13 pm

The heat is due to wasted energy in the inductor, normally the result of its resistance, not sure what inductors your using so its difficult to judge.

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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby arhi » Fri Sep 02, 2011 7:18 pm

Folknology wrote:If you have the chip in a dill socket remove it and remove supply connection (Strip board version) and measure the resistance between pins 6 & 7 to make sure it's 0.5 ohms and not 3 ohms.


I soldered it down to stripboard now - no socket, wanted to avoid all possible causes of trouble after it didn't work the first time. I removed the power, discharged the caps and measured resistance between 6 and 7 - got 0.5R (0.4-0.6, my multimeter don't go well below 1R)

Folknology wrote: Obvious check are the sense resistors are the correct value, for instance 1 ohm and not 10 ohms for example.


no load - I get 5.00V so I'd say sense resistors are ok

Folknology wrote:Your inductor needs to be about twice the max rated current by the way, you should also choose one with a low resistance normally a power inductor.


uh I was seriously afraid of that :(. I assume these inductors packed in 1/4W resistor like cases can take few mA only :( (cannot find a datasheet) ... I tried now with 50mA DC rated inductor and it worked bit better (inductor is as I noted 100 times larger) but it got very very hot very fast :( ...

Folknology wrote:The latest values you use are better than the previous as those were incorrect (ct = 75pF is bad, operates at more than twice the rated frequency of the device!).


the 75 was a test of higher freq (I hoped calc will prevent me to go out of range of the device)

Anyhow, seems the issue is with inductor - a one with fat wire is required :( ...

what is weird is that this other one (1uH) on the output does not get even warm (the "optional filter") and all that current has to go trough it too ?! .. any ideas what is the "default" rating for these 1/4W resistor look a likes ?

(THANKS a bunch for joining in on discussion)
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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby arhi » Fri Sep 02, 2011 7:23 pm

Folknology wrote:The heat is due to wasted energy in the inductor


:D usually is :D inductor, resistor .. I just kinda ignored the point that all current I draw go trough L .. as I mentioned that second inductor is also in the 1/4W case and it does not get warm and all the current have to go trough it too

Folknology wrote:not sure what inductors your using so its difficult to judge.


attm L is this one: http://nl.mouser.com/ProductDetail/Fast ... FZWw%3d%3d

before that I used 220uH one that looks just like 1/4w resistor only it is green :) (brown, black, gold, silver on the 1uH for e.g.) no idea what the power rating is ...
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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby Folknology » Fri Sep 02, 2011 7:27 pm

Make sure those inductors aren't just wire wound resistors of course!

something like one of these (with the right inductance) would probably work : do a google search for "STANDARD-RADIAL-LEAD-INDUC-0-6A-470UH-88-1039" that should point to an inductor at rapid electronics. I would use a direct url but the spam bot here won't allow me to ;-)

regards
Al
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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby Folknology » Fri Sep 02, 2011 7:34 pm

If you are drawing 250ma with that inductor having a 58ohm dc resistance (effectively in series) the power consumed and mostly runed into heat would be:

P = I*V = I*I*R = 0.25*0.25*58 ~ 3.6 watts i.e. small heater!

Also a voltage drop will effectively build up across the series resistance of the inductor, if you do the math you can see why things start to break down prematurely.

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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby arhi » Fri Sep 02, 2011 7:56 pm

Folknology wrote:that should point to an inductor at rapid electronics


looking at pic these look like "medium current" inductors. And according to rapid the current rating drops with inductance, the 220uH one is rated 250mA so "right there on the limit" and 1uH is 1.2A so that explains why the 1uH is cold and 220uH is cooking. I do not have anything to compare those pics to so these might even be "low current" ones so 220uH is 130mA (1uH is 640mA) and that would also fit the pattern ... anyhow they are underrated for current I need to draw (especially as you said that I need to double the rating I need - or that was just a safety ?)


Folknology wrote:If you are drawing 250ma with that inductor having a 58ohm dc resistance..


yup, the resistance on these devices is huge I hoped the resistance would be below 1R, 50+R confused me a lot!!

btw this 220uH measures around 5R so matches the table for low current inductors (so it's 130mA rated :( ) ... that kinda explains it all ... I ordered some 1A (0.19R) and 0.5A rated ones (1R) to repeat the test tomorrow, but I fear they are going to be physically much bigger then what I expected :( ... this 1uH on the output can stay as even if rated only 640mA (low current one) it's going to be more then ok for 240mA current draw :)

Thanks for help
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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby ian » Sat Sep 03, 2011 1:49 am

Ack, I'm a little late to the party today ;)

Thank you for the analysis of my iron. I will do some further testing, and maybe pop open the station. I opened it before, it is an all through-hole PCB.

p.s. also to repeat my request to route all leftover port pins of a mcu, for future development, like adding more buttons, leds....


In so much as it is possible, this will be done on my controller. I also decided to switch to 18F2550 while trying to fall asleep last night, the EEPROM and 5V are too attractive to go with a 24F.

Ian, there are laws (international?) about selling prototypes or are you just applying "good sense" to chose what is sellable and what not? No CE/FCC marking needed if you say it is a prototype?


On circuit boards and even kits there is the implied risk of using hot-pointy things and DIY, so (as adafruit told me) it is probably not worth worrying about being sued. However, as arhi says, even if you're not liable for damage it doesn't stop a costly lawsuit. More generally speaking, I would feel super bad if something I worked on/sold hurt someone or caused damage.

Ian, one hint. I use a "cable" fuse holder with 2.2A fuse on my 24VAC input into iron. Maybe it would be a good idea to add a fuse holder on the pcb too ? (I used pcb mounted fuse holder on my initial board)


Will do.
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Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri

Postby arhi » Sat Sep 03, 2011 5:54 am

ian wrote:Thank you for the analysis of my iron. I will do some further testing, and maybe pop open the station. I opened it before, it is an all through-hole PCB.


Then by all means please trace the schematic on original controller and use that to detect sensor and heater. I already made a mistake once and it's a easy one to make. Also adding original schematic to the threat might help someone in the future :)

ian wrote:In so much as it is possible, this will be done on my controller. I also decided to switch to 18F2550 while trying to fall asleep last night, the EEPROM and 5V are too attractive to go with a 24F.


:D :D :D 18F2550 was btw my first choice for this device :D then I decided to go with 16F690 to "get rid of it" :D

one more project to polish on new open source usb stack :)

I now need to wait for this inductor to arrive. I ordered some 330uH 1A and 0.5A inductors but I think they will arrive Monday or Tuesday :( to try the 5V regulator... from what I seen yesterday the latest schematic should work, the only problem is the pcb as I have no clue what packages those come in. But they obviously ain't gonna be SMD :(
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