Another Weller Question

martin griffith wrote in news: snipped-for-privacy@4ax.com:

What if it's a zero-crossing temp-controlled iron?

No problem with a straight resistance iron,but newer soldering irons are often temp-controlled.

The 24 volt Magnestat (WTCP) irons work on DC just fine (been running one on a little universal SMPSU for about a decade - lighter in the baggage and works in all countries) M

I'm thinking the thermostatic switch might suffer more from arcing perhaps on DC.

Graham

thats what i was thinking as well. Supose I'll just have to sell the campervan

martin

For AC use I soldered a diode across the switch. This minimizes duty cycle and the temperature swings. The transformer is apparently beefy enough not to saturate.

"Boris Mohar"

Sounds like a VERY bad idea !

With such a diode, power supplied to the iron cannot drop below 50% - so with a 600F or 700F tip fitted it would be *dangerously overtemp* when not in actual use.

In this condition it could NEVER cycle !!!!

You never tested it or you would know otherwise.

....... Phil

The Magnastat irons I have dismantled since the mid 1970s have had a capacitor across the switch, the earlier ones didn't.

When I first saw they had fitted it, my concern was that the switch contacts would be eroded by the discharge current of the cap. but that doesn't seem to be much of a problem (other things usually break first).

How do u test the "SWITCH" ?