Repairing Yihua 898D+

[DEXj98]

Hi everyone, I've been using this chinese 2 in 1 rework station for quite a while (maybe 2 years?) but it has stopped working since yesterday, when I tried to turn on the hot air and this happened (see photo attached): the temperature display showed "4" degrees and the air coming from the nozzle was cold. The soldering iron seems to work but the display sometimes goes crazy showing random numbers on the right side (the temperature display of the soldering iron). Now this seems to be over but the hot air still has the same problem as before.
Anyone had this problem before with similar stations? Thanks!

[Ordinaryman1971]

I have one of those too. The hot air assemblies are pretty cheap... $10, the irons are $6, replace both and it will work again.
The intermittent readings are due to cheap wiring. The iron wire you can disconnect, it's in the socket, but the hot air gun is permanently connected as in mine. You can buy the hot gun with a socket connection and just mount it in the enclosure... for future repairs.
 

[DEXj98]

I have one of those too. The hot air assemblies are pretty cheap... $10, the irons are $6, replace both and it will work again.
The intermittent readings are due to cheap wiring. The iron wire you can disconnect, it's in the socket, but the hot air gun is permanently connected as in mine. You can buy the hot gun with a socket connection and just mount it in the enclosure... for future repairs.

I checked the hot hair gun and it seems to be fine: the internal resistance is about 75ohms, the thermal sensor varies it resistance with changes in temperature, the handle positioning sensor works, the fan starts and is adjustable, but it has no voltage delivered from the unit. There are some resistors in series to all lines, covered in shrinking tube, but I haven't checked them yet.

[Rasz]

triac or microcontroler, and since you said both sides went bad maybe microcontroller power supply

[PKTKS]

I have one of those too. The hot air assemblies are pretty cheap... $10, the irons are $6, replace both and it will work again.
The intermittent readings are due to cheap wiring. The iron wire you can disconnect, it's in the socket, but the hot air gun is permanently connected as in mine. You can buy the hot gun with a socket connection and just mount it in the enclosure... for future repairs.

YES  cheap..  Worthy cheap tools.

 Yihua 898D+  or YAXUN 878D+   they look same chassi base

it would be nice to have the working SCHEMATIC already posted to do the replacement.
Whoever needs that will certainly spend some time checking the wiring.

Paul

[chemary]

Just found that some guy created a schematic analyzing the circuit and also has an interesting video fixing the issue he had with the hot air gun.
https://github.com/acbaruth/898D

In my case I was looking for info about my problem with the soldering iron, it worked intermittently. When you move the cable sometimes it displayed "5-E", I found it was a broken cable but after replacing it still sometimes doesn't heat event it's no longer displaying the error. I replaced the heating element as I thought it was the internal thermocouple but it didn't fixed the problem either. I disassembled the unit looking for bad caps as after 7 years of operation I could have degraded, but they looked fine so I closed the case and now it seems it's magically working fine, so my guess is that it was a cable inside not correctly connected.

[gurj1979]

Hi guys. I hope someone still reads this.
My 898D+ heatgun failed due to sized fan, which fried the TIP122. Replaced heatgun and TIP122.
All works, but the heatgun it always giving MAX heat regardless of being set to 100°C. So I replaced the heatgun again but from another supplier, but same thing.
I can't find any short circuit on the PCB anywhere.
Can someone please here.
Thanks