WX0B relays are pretty tough, I have had many direct lightning strikes and
no relay damage - even with no MOV protection near the relay.
I have had MOV's short after a direct hit, so sometimes they fail closed. I
always replaced any that were obviously burnt even if open.
Subject: [TowerTalk] MOVs in Stackmatch
From: Pete Smith <firstname.lastname@example.org>
Date: Wed, 03 Jun 2009 17:15:40 -0400
I am repairing a Stackmatch that was damaged by voltage induced on
the control lines by a nearby lightning hit. Most of the traces
going from the terminal strip to the hot side of the MOVs protecting
the relay coils are gone. Do MOVs fail open or closed? Is there any
way with minimal equipment to see if an MOV is still good? The relay
coils all appear OK, so I guess they did their job.
73, Pete N4ZR
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