Add a power indicator to the FX888 soldering station, help needed. - Page 1
Forum section: electronics / projects

author: Vitticeps
author_rank: Newbie
timestamp: November 25, 2011, 04:27:45 am
content: Hello everyone, I am new here and have come seeking help with what I thought would be a simple project.I want to add a power indicator LED to my Hakko FX888 soldering station. The problem I am encountering is that it seems that no matter where I attempt to pull power from on the circuit board, it interferes with the operation of the circuit.Has anyone attempted this mod successfully and if so, can you give me some guidance on how you did it?

author: SgtRock
author_rank: Unknown
timestamp: November 25, 2011, 05:14:27 am
content: Dear Vitticeps:--I am not familiar with the schematic of the FX888, but if it is similar to the 936 the attached PDF file may be of some help. I have made this mod to both of my 936s and I love it. The PDF includes a 936 schematic. I could not find an FX888 schematic anywhere. If you have one please post it. You might have to play with the resistor value. Let us know if this will work or not."If you build a better mousetrap, you will catch better mice."George Gobel 1919 1991Best RegardsClear Ether

author: IanB
author_rank: Super Contributor
timestamp: November 25, 2011, 05:17:28 am
content: What do you want to do? Do you want to have something that lights up all the time the power switch is in the on position?If so, perhaps you can find a way to take power directly from the mains supply after the on/off switch and derive a low voltage feed from that? I have not taken my FX-888 apart so I don't know what's inside. I usually follow the advice that "if it ain't broke, don't fix it".With my FX-888 I know it is switched on because the power indicator light flashes and it hums when it's heating the tip. When I hear the humming I know to turn it off.

author: Vitticeps
author_rank: Newbie
timestamp: November 25, 2011, 09:48:19 am
content: Yes, I am wanting to add an LED that stays on as long as the power switch is turned on. There isn't really enough room inside the case to add my solution to bring the mains supply down to a usable voltage.I don't have a schematic, I was simply probing around and trying to find a line that is always on regardless of whether the circuit is heating the tip or not. Trouble is that any of the areas I have tried end up either preventing it from heating or making it heat continuously. Maybe I do need to play with the resistor value some more.I'll report back if I find a good solution.

author: david77
author_rank: Frequent Contributor
timestamp: November 25, 2011, 09:54:43 am
content: Why don't you simply use a small neon indicator that can be wired parallel to the mains side of the transformer? They are available in very small sizes, too.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: November 25, 2011, 10:47:22 am
content: Why you simple you dont take 28 VAC from transformer, the part count will be minimal?

author: Clayton
author_rank: Contributor
timestamp: January 09, 2012, 12:20:12 am
content: I hope it is not too late to add to this thread.Yes I also thought that the Hakko FX888 needs an 'on' status light especially after I accidentally left it on for 5 hoursSo my thoughts are to replace the red led with a bi coloured; red/green one. The red will use the same trace as the current red led. This will also be the input to the base of an npn transistor configured as a not operator. The output goes to the green.So when the red lights the logic to green is low and when the red is off the logic out to green is highNow I still haven't found such an led in my junk box yet...

author: samgab
author_rank: Frequent Contributor
timestamp: January 09, 2012, 01:25:54 am
content: Would a simple way be to swap out the on/off power switch with one that lights up when on?The switch is off at the side, but should still be visible...Or am I misunderstanding the OP's goal here?

author: IanB
author_rank: Super Contributor
timestamp: January 09, 2012, 02:28:33 am
content: I simply unplug my FX-888 (and other items) when I go away from the bench. Then I know it can't be on.If the location makes unplugging inconvenient I have a master power switch that I turn off when I go away from the work area.It's a good work habit to ensure that the main power is turned off whenever you are not working.

author: Clayton
author_rank: Contributor
timestamp: January 09, 2012, 03:00:10 am
content: Yes these are possible solutions and good work habits.Thing is, I happen to like Dave's take it apart approach and mod it if you can

author: The_Penguin
author_rank: Regular Contributor
timestamp: January 09, 2012, 03:14:07 am
content: Quote from: SgtRock on November 25, 2011, 05:14:27 amCool, nice to have a schematic. Thanks!!