My trusty Metcal iron ( 20 yrs old) is causing problems. I have a small PCB with a PIC and a couple of LEDs. No power to the board... If I touch the cathode on the LEDs, they light up!!!!( anode goes to 1k and then to IO pins on the PIC. WHY??? HOW?? RF injection? It's just the board on the bench...
Strange Metcal problem
Oct 28, 2026
Last reply: 4 hours ago
4 Replies
Unlike most irons with ceramic elements, Metcal uses RF for heating. It sounds like you have some kind of leakage from the iron to the board. I expect they would normally want to keep the tip isolated, but perhaps that's broken down? Try an insulation resistance tester between the metal outer and the pins of the handpiece cable.
To avoid further troubles I'll probably look at replacing the cartridge - unlike the irons, they aren't super expensive.
Theo
Thx I'll try that. I have lots of other tips I can try...
Fun! Scope it.
The combination of Mantis and Metcal and Dremel is wonderful.
John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
I probed my Metcal tip and saw some wimpy spikes, probably not enough to light an LED.
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