KSGER T12 - Tip not grounded - Page 1
Forum section: electronics / repair

author: blallo
author_rank: Newbie
timestamp: January 22, 2024, 11:19:43 pm
content: Hello everyone,i have a KSGER T12 without internal psu, it's powered via a 24v dc external PSU.Today i noticed that while i was soldering a led, it turned on slightly, so i suppose the tip is not grounded.Do you know how to solve this?Thank you!

author: thm_w
author_rank: Super Contributor
timestamp: January 22, 2024, 11:38:09 pm
content: Open it up, you should see a point on the secondary side you can solder a earth wire to.https://www.eevblog.com/forum/dodgy-technology/dangerous-solder-station-ksger-t12/

author: blallo
author_rank: Newbie
timestamp: January 24, 2024, 07:21:16 pm
content: Quote from: thm_w on January 22, 2024, 11:38:09 pmSadly that's not my case, i have a single board without the psu board, i power it via an external PSU (it's like a laptop psu with barrel plug)That's my mobo:

author: BrokenYugo
author_rank: Super Contributor
timestamp: January 24, 2024, 08:07:04 pm
content: See the big hole marked "PE" in the lower right corner? That's the earthing/grounding point, "Protective Earth".

author: thm_w
author_rank: Super Contributor
timestamp: January 24, 2024, 10:51:59 pm
content: Quote from: blallo on January 24, 2024, 07:21:16 pmCheck if your laptop PSU is grounded/earthed, measure resistance from output barrel to earth ground. Some already are.If it is not, you'll have to either get an earthed PSU, or wire up a ground lead yourself. Sometimes done by (carefully) hacking up an old power cable.

author: elektryk
author_rank: Regular Contributor
timestamp: January 25, 2024, 08:28:54 am
content: Some of such "power bricks" can be easily opened.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 26, 2024, 11:29:22 am
content: I would not recommend hard-grounding the tip.If you are going to solder only de-energized boards, it is quite acceptable, but sometimes you want to keep the power on during repairs.Do this through a 1M resistor - for a static charge, this will be enough to drain.Modern LEDs can glow when the wind blows.

author: floobydust
author_rank: Super Contributor
timestamp: January 26, 2024, 08:54:47 pm
content: A 1MEG resistor is OK for ESD grounding - a wrist strap, a workbench etc. but not for a soldering iron, especially one that has a transformer wound by villagers.One person tried it on their KSGERlook at the scope tracestip went from 180Vp to 122Vp with the 1MEG added, not much help. This is with the KSGER PSU.High quality laptop bricks, two-prong can have low leakage. Just measure ACV from tip to PE. I do see a 1MEG used in them though.Best is a three-prong laptop brick.

author: elektryk
author_rank: Regular Contributor
timestamp: January 26, 2024, 09:13:50 pm
content: My notebook PSU used in soldering station has 1M resistor with parallel capacitor between earth and output ground, other one layin' around has 0.1R measured with multimeter, so its definitely hardwired by the manufacturer.I use the first one, AC multimeter shows about 0.4V and 0.04mA beetwen tip and earth connection but it is able to lightly glow red LED, which blinks with a similiar frequency as the heater.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 27, 2024, 02:09:42 pm
content: Quote from: floobydust on January 26, 2024, 08:54:47 pmMaybe the induced voltage has a high frequency and penetrates due to the parasitic inductance of the conductors?I would try adding 10 nF to PE capacitor.