The X-Cap-Files

These are directly on the power leads. I generally just cut them off. Dwight ________________________________ From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Charles via cctalk <cctalk at classiccmp.org> Sent: Tuesday, June 2, 2020 3:05 PM To: cctalk digest <cctalk at classiccmp.org>; Jon Elson <elson at pico-systems.com> Subject: The X-Cap-Files Today I was working on a new-to-me VT240 which hadn't been powered up in a long time (possibly 10 years). Hooked it up to an old 9" B&W CCTV monitor and everything was running fine for 20 minutes or so - when suddenly an astonishing amount of acrid whitish-gray smoke started pouring from the vents =8^ O So I yanked the power cord out and took the case off. Sure enough, one if not both of the 0.1 uF X-caps on the line filter had cracked open and my nose confirmed that was the source of the stench. Fortunately there is no damage to the PC board or surrounding components - even the caps don't look toasted, just split. Good thing I was sitting right there when they failed and could turn the power off immediately. I've read here and elsewhere about the spectacular failure modes of these caps, sometimes flames, but this is the first time I ever experienced it first hand. Maybe it's time for a look inside my VT220? ;) -Charles