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| Soldering station Quicko T12-943 no power |
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| Haggis McHaggis:
--- Quote from: floobydust on May 20, 2019, 08:02:07 pm ---There is a high risk if the DC adapter (or bench PSU) is already on and then you plug it (DC) into the soldering station, a surge occurs that can make an overvoltage spike and damage the controller. It's due to the cable inductance and capacitors. Best to plug in AC power last. --- End quote --- There is a power on/off switch on this device. Is this switch going to cause the same issue when the DC adapter is already plugged in? If yes, this switch would be a bad idea and should be removed, right? |
| floobydust:
Where is the on/off switch - in the brick or at your soldering station? You want to avoid the laptop adapter is powered on making 20V, and then you plug in the DC jack to the soldering station. The capacitors in the brick dump into the soldering station and create a surge. I don't know which components are delicate on the T12-943. Perhaps Quicko is using 25V capacitors on their 24V controller, or a 30V IC. For surges, a big TVS diode like 1.5KE27A at the DC jack is what I would consider. A TVS diode cannot allow 24V but clamp to 25V. Their clamping ratio is not so tight. |
| Haggis McHaggis:
--- Quote from: floobydust on May 22, 2019, 01:31:08 am ---Where is the on/off switch - in the brick or at your soldering station? --- End quote --- On the soldering station. You can see the switch on the first photo in the opening post (Quicko resistor to switch.png) |
| Specmaster:
As floobydust mentioned in an earlier post and on your other thread (not too sure why you opened another thread for this), Quicko says T12-943 must be limited to 25VDC max. input voltage and the type of PSU you are using has low current AC voltage of upto 90V leaking onto the DC output and it is this that has possibly caused your problem. As I mention on the other thread, I believe the solution is either feed the iron with pure 24V from a battery or to replace the whole unit with a Quicko T12-952 with the dedicated Quicko PSU built in the case. |
| floobydust:
We don't know what Quicko T12-943 parts are failing, draza did not mention. Let's assume it is sensitive to overvoltage transients on DC power. The DC on/off switch would cause a power on spike and is trouble. Consider: LT AN88 Ceramic Input Capacitors Can Cause Overvoltage Transients for detailed analysis and notice the spikes can approach 41Vpk. |
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