Yihua/Standig/Yum Cha 937D Soldering Station - got one?

[Shock]

Anyone have one of these cheap soldering stations?  Ever looked inside?

Looking at the layout looks pretty simple inside I'm guessing those ICs should all be readily available.
I've seen some video clips of Yihua showing their irons are close to calibration as well.
Maybe thats what V1 102 is for?

I'm weary of getting cheap stuff but my plan is to get two of them (which I need).
They seem to be similar iron and tip setup to Hakko so I might load em out with Hakko tips if needed.
Not really concerned with the stand (they come with one) but I like the black box and the potentiometer control.

For 2 stations $100 rather than $400. What do you think?

[SLJ]

The Hakko FX-888 has been discontinued and the replacement uses buttons.  No more knob.  After looking at a few different stations I suspect they are all coming out of one or two factories. Not familiar with this one.  Check to see what you have to do for warranty replacement.  The tips/heater might be compatible with a Hakko but I'd have to see them side by side to tell. 

[T4P]

No, they don't. You can use hakko heaters but the temperatures will be very off.
The specific heaters that come from china uses those thin 4 wire ones which are thermocouple-based and a replacement that easily searchable is the one from Atten

Oh yes, this station is actually better known as a 936D which are just digital incarnations that the chinese thought of but it's still a 937D in china and only Yihua uses the "D" moniker at the back, which they like to do so.

[amyk]

The only IC not easily available is probably the uC on the digital ones, since it's programmed with custom code and likely protected.

The non-digital Hakko clones all use a simple all-analogue control loop.  The trimpot is for calibration, the Hakko had it too.

[Bored@Work]

After looking at a few different stations I suspect they are all coming out of one or two factories. Not familiar with this one.

As how many companies produce Hakko clones, that is difficult to say because of all the rebranding going on. I think maybe more than two,. Atten, Ayoue, YiHua would already be three.

The "YH" on the silkscreen would indicate this one was really produced by YiHua (Guangzhou Yihua Electronic Equipment Co., Ltd), http://www.gz-yh.com.cn/newEbiz1/EbizPortalFG/portal/html/ProductInfoExhibit2.html?ProductInfoExhibit_ProductID=c373e9254d4449268f7faca8b2c502bd&ProductInfoExhibit_isRefreshParent=false

[T4P]

There are 3 OEMs of 936 clones namely, YiHua Atten & Aoyue
But the no.1 rebadger is YiHua, atten not so much but Aoyue not at all

[KingsTwisted]

I had this station and it died 6 weeks after getting it.
It was a blown Voltage regulator (which blew the controller).
Nothing else was effected, and the vendor is sending a new board, but...

As an exercise, I drew out the schematic (see attached).
If it happens again, I'll write a program for a MicroChip MCU.
NOTE: MicroChip's Vss/Vdd are opposite of SamSung's MCU.
In the mean time, hopefully others will find the schematic useful.
(I certainly found it useful as a training exercise )

[KingsTwisted]

Apparently I have no patience,   I went ahead and wrote the program. 
(see attached).  I used a MicroChip pic16F1509 with SourceBoostC.
NOTE: SourceBoost has a limited free compiler that works for this program,
           but I liked BoostC so much AND it was cheap, so I bought it.

   For anyone who cares about the GORY details...

I added a few features to the Soldering Iron.
  1) Idle timeout sleep (20 minutes without fiddling with a button/dial)
  2) Display temp of hot iron (if the iron is hotter than what the dial is set to, display its temp).
  3) Allow temp to be set to a low value (50+ degrees Celsius)
  NOTE: Be prepared if you read the code, I write VERY dense code... but it has good comments.

I also modified the board:
  1) Swapped V+ and Gnd for the MCU (Microchip has them swapped compared to Samsung)
  2) Replaced wire R19 with 1K resistor (keeps the F/C switch from directly connecting to ground)
  3) Added a 1K resistor between MCU pin18 and "Temp Dial" pot
      (Otherwise, pin18 would have a direct connect to V+  or GND if the Dial is set High/Low)
  NOTE: I suspect one of the Pins directly connected to Ground/V+ caused an inrush current surge (high dI/dt)
             that blew the MCU & Voltage regulator.  Bad code or a bad MCU startup condition could have caused this.

I also don't like that fact that they use a single diode as a "bridge rectifier" for the control circuitry, BUT I didn't fix that.

[KingsTwisted]

   *******************************************
   **** SCHEMATIC  ***  and  *** PROGRAM CODE ****
   *******************************************
   **********   Attached in above posts     **********
   *******************************************

[Shock]

Nice work KingsTwisted, it's a shame you aren't working on the Yihua 936. 
In the end I picked up 4 of them from hobbyking.com (search for yihua).

At $15 each I thought this station would be great for modding as well.

 

[amyk]

The 936 has not a lot of scope for modding; it's a pure analogue controller.

Odd that they used a relatively obscure Samsung MCU instead of a PIC or AVR (or one of the ultra-cheap Chinese 8051s)... they might've gotten a good deal on tons of them.

[trisonic]

I had this station and it died 6 weeks after getting it.
It was a blown Voltage regulator (which blew the controller).
Nothing else was effected, and the vendor is sending a new board, but...

As an exercise, I drew out the schematic (see attached).
If it happens again, I'll write a program for a MicroChip MCU.
NOTE: MicroChip's Vss/Vdd are opposite of SamSung's MCU.
In the mean time, hopefully others will find the schematic useful.
(I certainly found it useful as a training exercise )

Hi

i have the same solder station, and i'm trying to calibrate with the blue trimmer.
but its too sensible, if I try to calibrate it a little, the temperature changes by several degrees.

how can i mod it?

thanks

[MrAureliusR]

Wow, this is awesome. I've had my YiHua 937D for over two years now, and I'm still on the original heating element! Not bad for the $50 or so I paid for it. I've bought tons of replacement tips for it, I find the Plato brand ones are excellent quality (they are replicas of the Hakko ones) and they're usually a few bucks cheaper than the Hakko ones. The heating element is working fine still, but it looks pretty beat up -- my 937D came with a replacement one, so I'll have to install it soon.

I am really interesting in hacking this iron as well -- when I get some time I'll definitely take a look at your code and I might port it over to an MSP430, or even just change the code so it compiles in MPLABX. Perhaps we can put the code on Github and work on it? One of the big features I want is the auto-shutoff. I might even hack a detector into the iron so it can tell if it's in the stand. Because I use a different stand than the one that came with it, I think the easiest way to do this would be to add magnets in the stand and add a reed switch into the handle. It'd be easy to write a routine to detect this and cut power to the heater.

I was actually fairly impressed the first time I cracked mine open. The quality of the transformer and main board are miles better than what I was expecting. As you noted, most of the parts are off the shelf and easily replaceable, which I like. For such a cheap iron, it's a real trooper! I find I get great results with it. It works better than the irons they have in the labs at school! (But that's mostly because they're cheapskates and don't replace the tips nearly enough, the newbie students always wear them out quickly).

[Shock]

My $15 Yihua 936s are still happy. I'm using genuine tips and have calibrated the irons and that is about it. The less you have to change out tips, the better in my opinion.

I don't like the idea of modding the iron or the holder. The three ideas I came up with:

1. If you can detect that the iron is cooling (due to soldering) rather than warming idle, then go into standby after a period of idle time elapses.

2. Automatic timer at ~20 minutes, a few minutes before the timer is up you get an audio warning, if a reset button is not pressed the station will enter standby mode. Audio beeps will continue warn periodically that the station is still on.

3. Use a ready made product like the Jackson count down timer. It will turn off your whole soldering station after 30/60/180mins (perhaps mod potential here as well).