Huako 858D Rework station Teardown and Safety Evaluation

[klh2000]

Well, since I have started getting into SMD soldering and was tired of melting heat shrink with my soldering station, I thought it was time for a hot air station. I decided to go for a cheap Hakko knock off (Huako ) because I couldn't find any cheap, used name brand ones.

 

These cheap hot air stations are known for grounding problems, so let's see!

 

Included in the box is the power supply, air gun, three tips, and a poorly written manual.

 

 

The earth connection is connected to the tip, so far so good...

 

 

Top view of the board, which seems to be revision 1.0, and have a micro controller with the p/n scratched off

 

 

And here is the earth wire with a little bit of hot snot on the side. Although the earth wire is crimped to a lug, it is improperly connected to the case through a stand off. This is a safety issue that I'm too lazy to fix

 

 

This is the hot air gun itself, which is more ergonomic than the picture makes it look. Time to take it apart!

 

 

There isn't much to see besides a small pcb for the wire connections, the heating element, and a squirrel cage/blower style fan.

 

The soldering looks horrible on this. it is much worse than on the main control board.

 

 

 

 

And here is how the tip is grounded, This is completely unacceptable. It is intended to just be clamped against the metal shield that contains a heating element that is live at mains voltage!

 

 

 

 

 

Well, I guess can't really complain about the quality issues considering that it only cost $30USD including shipping. The only major issue is the way that the tip is grounded, there should be a metal tab on the hot end with the wire soldered to it. Other than that it is a decent unit for the price and does perform it's intended functions.

[iamdarkyoshi]

Sometimes if you lick the microcontrollers and wipe it off, and then wipe some thermal paste across it, the number may appear. Sometimes.

 

Anyway, my 3-in-one station was far worse for safety. My favorite feature was the chassis reaching 150°C when using the bench supply.

[Hackentosher]

3 hours ago, iamdarkyoshi said:

Snip 

And here I am feeling slightly ripped off with a spark fun branded hakko clone. 

[Huntsman]

Atten has one that looks like this. Also another that has soldering station functionality. How's the temperature regulation tho? I wouldn't buy it for even 1 buck if the regulation is no good.

[klh2000]

7 hours ago, Huntsman said:

Atten has one that looks like this. Also another that has soldering station functionality. How's the temperature regulation tho? I wouldn't buy it for even 1 buck if the regulation is no good.

I have misplaced the thermocouple for my multimeter, so I can't check that right now

 

[iamdarkyoshi]

23 minutes ago, klh2000 said:

I have misplaced the thermocouple for my multimeter, so I can't check that right now

 

My temp regulation on mine is quite good. I have done SMD soldering with it.

[mariushm]

The tip is NOT live at mains voltage, the wire inside the ceramic heating element is working with 24v AC, and should normally be insulated inside the ceramic element.

That's why you have a triac on the board, and a zero cross opto isolator driver (moc3041). The microcontroller simply measures temperature of the air flow  and turns on or off the power as required, to bring the temperature to specific levels.

 

There should be a more reliable connection to ground (crimped cable or something) at the tip, but the existing design works.

 

I agree with the horrible soldering on that tiny pcb, looks like not enough temperature and flux. Also cutting excess leads wouldn't have hurt.

 

I think there's an open source alternative to the microcontroller source code in these things posted on EEVBlog forum. From memory, I think the microcontroller is some 8bit thing made by Samsung but it could be an ATTiny or some chinese 8051 based micro.

[klh2000]

47 minutes ago, mariushm said:

The tip is NOT live at mains voltage, the wire inside the ceramic heating element is working with 24v AC, and should normally be insulated inside the ceramic element.

That's why you have a triac on the board, and a zero cross opto isolator driver (moc3041). The microcontroller simply measures temperature of the air flow  and turns on or off the power as required, to bring the temperature to specific levels.

 

There should be a more reliable connection to ground (crimped cable or something) at the tip, but the existing design works.

 

I agree with the horrible soldering on that tiny pcb, looks like not enough temperature and flux. Also cutting excess leads wouldn't have hurt.

 

I think there's an open source alternative to the microcontroller source code in these things posted on EEVBlog forum. From memory, I think the microcontroller is some 8bit thing made by Samsung but it could be an ATTiny or some chinese 8051 based micro.

It must be switching the mains with that triac, it pulls 660 watts from the wall.

 

 

That tiny transformer will not be able to pass that much wattage through it. and even if it did run off of the 24 volt transformer, it wouldn't pull enough wattage to heat up. The resistance of the heating element is 20 ohms.

 

 24 volts: I=V/R: 24/20 = 1.2 * 24 = 28.8 watts

 

120 volts: I=V/R: 120/20 = 6 * 120 = 720 watts.

 

The 720 watts and six amps is fairly close to what it actually draws. I measured 121 volts at 5.56 amps, which gives me ~673 watts. At 24 volts that would require 28 Amps, which neither the transformer or the 22 AWG wire going to the air gun could handle.

[NicKzp]

Any1 trying to flash this controller?

[klh2000]

9 minutes ago, NicKzp said:

Any1 trying to flash this controller?

I wish I could, there are a few bugs in the operation of the unit. Too bad they scratched off the part number from the microcontroller.