TS100 issue. Inconsistent bit power?

[Hughieandrolf]

Hi. has anyone any idea what may be going on here?
I recently bought a TS100 soldering iron which came supplied with an angle cut  pointed bit. I bought an 2 additional chisel bits but I can't always get the chisel bits to to work reliably :-
When using my small "Portable" old HP laptop brick PSU rated 19V 1.58A (30W) The supplied angle bit works fine but when using the chisel bits, switching on from standby the iron "browns out" and reboots every second or so.  I tried 3 x 18650s in series and the iron works with all bits as it does with a 24V 4A  chassis supply  but it's not really portable. I tried measuring the current on a boost buck CC/CV PSU module with integral meter and the meter display just randomly flashes. https://www.eevblog.com/forum/Smileys/default/confused0024.gif   
Thanks

Steve

[Gyro]

It sounds as if your HP laptop brick is simply not up to the job and is going into an over-current protection /shutdown cycle. It is probably right on the limit with the original bit and just over with the new ones, especially when the tips are cold and it is running at 100% duty cycle.

If you look at the TS100 manual, it specifies a PSU current rating of 2.1A for 19V supply (40W), so you're a fair bit short of that.

I believe there has been to odd occurrence of a faulty, shorted element but the fact that they both work fine with Lithium cells and the 4A PSU seems to eliminate that.

It would probably be best not to use it with a repeatedly browning out PSU, worst case it might cause damage to the switching FET or  possibly even corrupt the firmware.


P.S. You're probably having no luck with your current measurement because the element is controlled by PWM switching and the duty cycle will be changing as the tip warms up.

[Hughieandrolf]

Excellent. Thank you Chris. A case of RTFM. 
Steve.