EEVblog #596 - World's Cheapest Soldering Station - Yihua 936

[Blanketduck]

Hi everyone, I'm new here (Adam is my name, introductions aside as I need to post this)...

This is the YIHUA 937: Newer, more expensive, and more scary. A digital version which retails for $40-$50 here.

10mhz 8-bit MCU @ 20 PINS @ 4KB ROM ( big endian - probably an 8051 )
SAMSUNG -> Q328E (U3) 20-PIN
S3F94C4EEZ - DK94
K903B1

http://www.samsung.com/global/business/semiconductor/product/microcontroller/detail?productId=6803

Fairchild Semiconductor 400V Optocoupler/Optoisolator Bridge
F -> MOC3041 (U2) 6-PIN
317Q

http://www.fairchildsemi.com/pf/MO/MOC3041M.html

General purpose dual op amp @ 0.6 V/uS slew @ 1.1Mhz @ 5V supply
LM358N (U4) 8-PIN
YR1006

http://www.st.com/web/en/catalog/sense_power/FM123/SC61/SS1378/PF63721

4-quadrant AC TRIAC (high voltage switch w/phase control, suggestive that this isn't a PID system)

BT137
600E
NXP -> PJA303 - A5 - 3 PIN
( SOLDER MASK SIDE )

http://www.nxp.com/documents/data_sheet/BT137-600E.pdf

Notice: Don't open the case without gloves. I got flux paste on my gloves. There might be other chemicals.
This is useable if you disassemble the handpiece and wash with a damp cloth and quality dishsoap (something like dawn ultra).
I highly suggest a commercial neutral PH quat @ 1:40 ratio to disinfect and remove anything on the plastic (I am a BSW also by trade)...
The reasoning is that everything has been recycled and nothing is new.

The way this was assembled it's suggestive that someone probably could die during the process, and it still would've made it out the door.
It was probably too scary to finish so they just put it in the case and sent it out. The soldering iron doesn't fit in the stand,
so they crack the top part to make it fit. Normally an adult would have clipped it off, and used a plastic deburring tool. You can get them
for metal too that has rough/rusted or problem edges.

Suggestions for improvement to the designers:
1.) Drill out the back, deburr the edges, put in an AC receptacle, only use 13 amp rated power cords
2.) MOVs + HRC fusing + MPX line caps/filtering

3.) Larger caps on the board for more charge on the plates = better thermal mass on the tip
3A.) This particular model is designed for explosions, so smaller caps, more space = less chance of PCB burns
3B.) Because of A + B = you would have to redesign this as a switching PSU (add quad-wave rectifiers + DC/DC converter + LDO regulators + more things this can't do, etc)

4.) Better wiring in the handle, next time use a micrometer to design your tips so it fits snug with the ceramic element ( I suggest designspark mechanical which is free )
5.) TRIAC needs a heatsink
6.) All those ICs can be replaced by a single SoC
7.) Get rid of the 100k potentiometer and replace with a rotary shaft encoder or something else
8.) New PCB with more than just one solder mask on the side ( FR2 doesn't cut it )
9.) Segment LCD display is a waste of time, graphic LCD instead
10.) The samsung MCU isn't because this thing is a PID industrial controller. It's not even remotely fast enough to be one.
12.) New case could probably more durable. The plastic standoffs on here crack or break if dropped. It
would be nice to see some metal threading in the standoffs so you can assemble, and disassemble it as much as you like...

I would suggest renaming the station to the YIHUA SOLDERING REVENGE CLASSICS...
(similar to creepypasta pokemon conspiracy theories)

http://creepypasta.wikia.com/wiki/Lavender_Town_Mysteries:_Missing_Frequencies_and_Lavender_Town_Syndrome_(LTS)

Here's the theme song if you want to use this soldering station how it is:

[Blanketduck]

This is not a bad utility iron: http://www.wellerred.com/products/40-watt-medium-duty-kit.php

Solomon SR998 power unit to convert it to temp control ( I haven't bought one yet to see if the wiring is good, it's cloned a lot also )...
This might be really scary, but worth modifying. You could probably build a good (PID temp controlled) version to sell to people who already have utility irons:

http://www.mcmelectronics.com/product/TENMA-21-7927-/21-7927

[Monkeh]

Suggestions for improvement to the designers:
1.) Drill out the back, deburr the edges, put in an AC receptacle, only use 13 amp rated power cords
2.) MOVs + HRC fusing + MPX line caps/filtering

3.) Larger caps on the board for more charge on the plates = better thermal mass on the tip

I'm really hoping this is an early april fool's.

[don.r]

This is not a bad utility iron: http://www.wellerred.com/products/40-watt-medium-duty-kit.php

Solomon SR998 power unit to convert it to temp control ( I haven't bought one yet to see if the wiring is good, it's cloned a lot also )...
This might be really scary, but worth modifying. You could probably build a good (PID temp controlled) version to sell to people who already have utility irons:

http://www.mcmelectronics.com/product/TENMA-21-7927-/21-7927

Without a temp sensor, you are better off just sticking the iron on a variac or a dimmer controlled socket.

[T4P]

Dave, some background info on the station.

It is a 35W unit not a 50W unit or even better, some are 60W
I posted a while back on the 936 clones I have and they truly pull 60W each. the yellow and blue one I have (888 in a 936 case ...) acts more like a 888 than a 936.
This is what you get for saving 12$ 

This is not a bad utility iron: http://www.wellerred.com/products/40-watt-medium-duty-kit.php

Solomon SR998 power unit to convert it to temp control ( I haven't bought one yet to see if the wiring is good, it's cloned a lot also )...
This might be really scary, but worth modifying. You could probably build a good (PID temp controlled) version to sell to people who already have utility irons:

http://www.mcmelectronics.com/product/TENMA-21-7927-/21-7927

Without a temp sensor, you are better off just sticking the iron on a variac or a dimmer controlled socket.

True actually. It is quite literally just a variac in a box. Turning down irons on a variac make them slower than they already are

Why can't these comrades invent something decent rather then copying someone else's work, and doing a crap job at it? Violating intellectual property seems like the only thing the communist Chinese are good at. They have has not progressed much further than making and flogging copy watches, as far as ethics and quality goes.

Westerners should not be buying this sort of crap on principle. People in poor countries might not be able to afford a good soldering iron, but people in rich countries have no excuse.

Besides, quality is remembered long after price is forgotten.

The $16 soldering iron is probably illegal. If "Yeehaa!" lied about the ESD Safe, it would make you wonder if it is CE marked honestly. There are plenty of back alley sweatshops in red China illegally marking equipment. In this case it is illegal here in Australia if it does not carry a C-Tick or RCM mark. Our government has lost control of this rubbish entering the country. I think you will find the soldering of the wires onto the transformer tab does not comply with UL-60950 and other safety standards either.

DON'T BUY IT.

That's why it's cheap. And yes, they actually have a proper shop. What you see here is the cheapest grade of their clones.

[Blanketduck]

IT'S 12AM: APRIL 1ST in Canada! Happy APRIL FOOLS DAY! Only comes once a year!

Here's a video of the YIHUA 937D turned on:

The punch line is this ceramic heater. It says "24V 50W TAIWAN" (fake numbers)...
It would be very surprising if this could even come close to the new weller utility irons.

You don't need any special PSU stuff like I mentioned, because this thing probably can't even beat a 10-25W utility iron...
It's just designed for looks, which is why all the safety stuff isn't real, and you'll find too much in one spot, and too little in another...
Why would you need the build quality of a 700W-1500W PSU? You wouldn't.
My alarm clock and my toothbrush are both much more sophisticated than both of these ( japanese made also )...

Also that SOLOMON SR998 is another product to make a quick buck. You won't need it in any way. There's a thermocouple
inside most of those weller utility irons, and they're insulated. They're MUCH safer than these crap chinese things. Trusting
one of these crap things to change the volts/amps/frequency/phase on those would probably destroy the iron, or the device itself.
They perform really shitty when outside of the spec they were designed for.

I doubt you'll see those SR998s, because they're probably eliminated completely.
I still want one, but it's because I love making fun of them. I'm sure you could get one if you wanted. A chinese dealer
over in eastern canada stocks them on ebay ( weberdisplays )... http://www.ebay.ca/usr/weberdisplays

I think next your review has to be WORLD'S CHEAPEST POWER SUPPLY (look at the YIHUA models there. I have almost
every single thing YIHUA makes except those. They're all hilarious/funny)... I love YIHUA! So entertaining!

[EEVblog]

Hi everyone, I'm new here (Adam is my name, introductions aside as I need to post this)...

Great first post, thanks for contributing. 

[Blanketduck]

I think you are entitled to your opinions. However they are of no value to me. But I didn't reply just to tell you that.

I do not like links to YT videos that don't clearly represent the destination video to me before I click on it. Not even if I also agree the joke was worth it. It wasn't. I pretty well knew what to expect in this case. It makes Google think I want to be shown similar pointless videos if I click on them.

Sorry about lack of embedding. I'll format it properly next time. Ah yes, google and it's search analytics! It looks pretty much like a YIHUA 937D because it's a smouldering, and unrecognizable object. Both band members did solder and build their own instruments (now dead for unrelated reasons)... I would probably be yelling out "I don't get it!" if I had purchased it for $60 and it started on fire.

It is nice to see if you want to build a competing low cost station which actually works. Of course I bought for other reasons. One of them is "group" revenge:

"The great liability of the engineer compared to men of other professions is that his works are out in the open where all can see them. His acts, step by step, are in hard substance. He cannot bury his mistakes in the grave like the doctors. He cannot argue them into thin air or blame the judge like the lawyers. He cannot, like the architects, cover his failures with trees and vines. He cannot, like the politicians, screen his shortcomings by blaming his opponents and hope that the people will forget. The engineer simply cannot deny that he did it. If his works do not work, he is damned." -Herbert Hoover ( 1874-1964 )
http://www.hooverassociation.org/hoover/speeches/engineering_as_a_profession.php

Hi everyone, I'm new here (Adam is my name, introductions aside as I need to post this)...

Great first post, thanks for contributing. 

Thanks!

[LEECH666]

Who needs stinking temp measuring, as long it melts the solder, QC passed and QC sticker applied !   

I think this is even more correct ... 

[Christopher]

I have the Atten 937b iron, very similar to this for home use. With $3 clone tips off eBay.

It is a nice iron for the price, obviously not a JBC (which I use at work), but gets the job done. I have soldered 0402 components as well as 2.5mm^2 wire and it does OK.

What do you expect for $20? It serves its purpose for me. If ever I have £200 "spare" for just soldering a few components a month, I'll buy a JBC or Pace iron for at home. In my dreams!!

[T4P]

IT'S 12AM: APRIL 1ST in Canada! Happy APRIL FOOLS DAY! Only comes once a year!

Here's a video of the YIHUA 937D turned on:

The punch line is this ceramic heater. It says "24V 50W TAIWAN" (fake numbers)...
It would be very surprising if this could even come close to the new weller utility irons.

You don't need any special PSU stuff like I mentioned, because this thing probably can't even beat a 10-25W utility iron...
It's just designed for looks, which is why all the safety stuff isn't real, and you'll find too much in one spot, and too little in another...
Why would you need the build quality of a 700W-1500W PSU? You wouldn't.
My alarm clock and my toothbrush are both much more sophisticated than both of these ( japanese made also )...

Also that SOLOMON SR998 is another product to make a quick buck. You won't need it in any way. There's a thermocouple
inside most of those weller utility irons, and they're insulated. They're MUCH safer than these crap chinese things. Trusting
one of these crap things to change the volts/amps/frequency/phase on those would probably destroy the iron, or the device itself.
They perform really shitty when outside of the spec they were designed for.

I doubt you'll see those SR998s, because they're probably eliminated completely.
I still want one, but it's because I love making fun of them. I'm sure you could get one if you wanted. A chinese dealer
over in eastern canada stocks them on ebay ( weberdisplays )... http://www.ebay.ca/usr/weberdisplays

I think next your review has to be WORLD'S CHEAPEST POWER SUPPLY (look at the YIHUA models there. I have almost
every single thing YIHUA makes except those. They're all hilarious/funny)... I love YIHUA! So entertaining!

I'm sorry to interrupt your streak but this beats a utility iron hands down. Actually maintains temp roughly (not heating to 480) and not baking itself if you leave it on for too long

[BravoV]

A little surprising they didn't use a switching supply to save cost. Maybe they realize that would make it way too suspiciously light...

What stinking switching psu ? 

All you need is a brick and some cheap glue or screws to stick it in there so it won't wobble ... 

[senso]

Is that thing real?

[Luciano2572]

Surprises me that's only 4$ more than my iron;
http://i57.tinypic.com/2h2h7b4.jpg
It was 14$, no base/holder ... had to buy one (+10$)
And the original tip melted 
next step is a hakko for sure


edit: removed IMG tags, its too big

[linux-works]

saves weight by using 'virtual transformer technology'.

[Blanketduck]

I'm sorry to interrupt your streak but this beats a utility iron hands down. Actually maintains temp roughly (not heating to 480) and not baking itself if you leave it on for too long

What a troll you are hahah! I love this place! I wouldn't have it any other way.
This thing surely bakes itself if you leave it on for too long, especially my version! If not it eventually dies. Murphy's law wins every time!
It's not a real hakko, so you can tell the company just wants to sell a working iron, and granted people have bought it and want to use it.

I personally think the station is too large and improperly designed. An OSHW board and power unit replacement would be great.
The handpiece is somewhat ok. You get what you pay for. 400C can be had @ 10W...

It was worth buying, because you can make an OSHW version, and it'll become the new MASS CLONED solder station!

It might end up looking like the Weller WSM1 compact soldering station... http://www.newark.com/weller/wsm1/digital-soldering-station-40w/dp/18T1408 ( here's the weller catalogue page #13 - http://www.apexhandtools.com/weller/pdfs/weller%20catalog.pdf )

Idea that I'm too lazy to act on: I'd imagine the best OSHW station would be around 80W. You could make a dual-channel version 160W version, with some kind of terminal block (impedance might be a problem, but it's a soldering iron), so you can replace the socket with one that matches your handpiece of choice: metcal, weller, JBC, pace, etc ...You could avoid legal problems, by just selling the thing as a programmable industrial PID controller with "optional software" and firmware, which the user installs at their own risk...

It would be a challenging thing as a lot of irons have specific frequency/power and waveform requirements...
(the one line answer so I don't have to say anything about sinusoidal/pulse/square waves and AC/DC conversion)

------------------------------------------------------------------------------------------------------------------
Here's something unrelated I found enjoyable. This why I love product design forums:

"There’s a saying: Arguing with an engineer is a lot like wrestling in the mud with a pig. After a few hours, you realize the pig likes it.
Once committed to a logically backed idea that they know to be true, there’s little one can do to change an engineer’s mind, except, of course, provide newly proven evidence to the contrary that the engineer can chew on as fact.
But it’s stating their idea and hearing opposing ideas that makes an engineer happier than a pig in mud. And why not? Arguing is an opportunity to open the mind to new ideas, to think, and to reinforce one’s own research and rational.
Unfortunately, not everyone sees it that way. For non-engineers, disputes can be more about winning than expanding a discussion."

http://www.edn.com/electronics-blogs/serious-fun/4428606/6/Why-engineers-are-better-than-everyone-else

[Blanketduck]

Yihua should market that all their soldering stations now come with rainbow sponges! Increased sales!

I started using rainbow sponges in my soldering stations after watching this thing on youtube:

[m12lrpv]

Well I polished the turd.

Sure the clone was cheap and nasty but the reality is that it's better than what I had which was not temperature controlled. It was also cheaper than what I could justify spending money on and it workes. It was no big deal to replace many of the components with stuff I had in my parts drawer.

Plus I needed something with a smaller tip than what I had because I was having issues soldering the 0805 and 0603 caps and resistors with my old iron so its a win for me.

[pickle9000]

@m12lrpv

Nicely polished, probably be worth changing the pot for that extra shine.

But seriously you where probably soldering with a sub-standard iron. The skill of the person soldering and the solder is critical to doing a good job and this is a good indication of that. Nice job.

[m12lrpv]

@m12lrpv

Nicely polished, probably be worth changing the pot for that extra shine.

But seriously you where probably soldering with a sub-standard iron. The skill of the person soldering and the solder is critical to doing a good job and this is a good indication of that. Nice job.

thanks.

I didn't have a 50k pot that was suitable otherwise that would have gone too 

I might order one when I order the name brand replacement for the Triac and the illuminated power switch.

I agree with the solder quality being an issue. I ended up wicking off most of the solder that was on there and replacing it with my multi core solder. The stuff that was on there would melt but wouldn't flow.

[linux-works]

you probably didn't have to remove the solder; just add real flux, let it flow and then clean the board.

[saturation]

This is a good video to show what clones or lesser soldering stations do not give you compared to the better brands, and where the extra cost goes into.  We've had many forum topics on it, but no video shows the deficiencies in action particularly side by side comparison, IPC quality vs iffy stations.

[m12lrpv]

I've just replaced the triac in mine with a NXP BT137 600D and now there is no transformer hum at all. I initially though I'd broken it when it went quiet but now it actually seems to work better.

Problem now is I can't use the previously audible hum to tell me that I've left it on.

[miguelvp]

So, because of my current budget (because of buying dev boards like crazy) and my older soldering iron being more crap than this, I got a clone but it's made by Tenma. It was 30 some dollars. I haven't opened it up yet (I know I should and I will).

One thing I'm doing is to get the hakko 908-CK conversion kit to make it a large Iron and got an extra 5 original hakko 908 chisel tips (for a total of 6).

It will take a bit longer to heat up, and the Tenma seems to heat up pretty quick, but I wanted to add the extra iron mass, so that at least it's decent. It seems like the conversion kit will fit fine but I'll have to wait until it arrives (not many available out there).

[Bored@Work]

I got a clone but it's made by Tenma.

Tenma is a Farnell/Element14/CPC/Newark/MCM/<insert company name of the day> brand. They don't build that stuff, they slap the name onto stuff build by others, to disguise the true origin.