Schematics for JCD 908S adjustable soldering iron

[stj]

Re: Schematics for JCD 908S adjustable soldering iron

but it's junk, a 230v element with no sensor.
even the best software wont make it into anything woth mentioning.

people who write firmware are after T12 and JBC cartridges for good reason.

[Pjatruha]

Re: Schematics for JCD 908S adjustable soldering iron

I did not give an assessment of that soldering iron, but only gave an example of the fact that the enthusiastic guys wrote the firmware for the soldering iron on a similar MCU.
By the way, a 4-wire heater is used in the soldering iron. That is, it has a full-fledged temperature sensor. Here is the diagram of that soldering iron.

[Sam Scarbo]

*** Please help to fix -- JCD 908s soldering iron auto shut-off at a moderately high temperature.

My JCD 908s soldering iron has an auto shut-off issue when I turn it on for about 10 to 20 minutes at a moderately high temperature like 350 degrees C.
When it shuts off, there is no LCD display. Unplug/re-plug does not work immediately until waiting about 20 minutes or so for it to completely cool down and then it will start working again.

Before it shuts off, I noticed that the LCD display flickers a little bit.

Any one knows how to repair this? Please help.

I have attached a photo of the circuit board.

I have ordered a new soldering iron of another brand, but I think it would be nice to repair this 908s so I have a backup. I own this 908s for about 5 or 6 years.

[Sam Scarbo]

The auto-shutoff issue has been resolved. I have soldered a few wires to the LDO to measure the voltages. Then, the issue was gone. Probably there was a cold solder joint on the LDO.