I have several spares of those cores. They are micrometals T225-2b cores. And
yes, overheating can crack the cores, at least a couple that I deconstructed
showed a hot spot and obvious crack. The basic problem with the way that
toroid is used is that the unused coils are shorted by the band switch, so when
you are on 40m both the 80m and 160m sections are shorted, on 80m the half of
the coils for 160m are shorted. This causes rapid heating from the high
circulating currents and in worst case scenarios the delryn (sp?) support melts
and can catch fire, as can the plate choke that is just above the toroid. For
use on 40m-10m rtty I modified one so it didn't have 80m/160m sections. For
80m I made one of them into a single band amp by removing the high band coils
and mounting two toroids in series on top of the rf deck instead of hidden
under the caps where there is very little air flow. Search for 'hf2500' on
this page for more fun stuff about that amp: http://wiki.k1ttt.net/History.ashx
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: telnet://k1ttt.net:7373
-----Original Message-----
From: Amps <amps-bounces@contesting.com> On Behalf Of gudguyham--- via Amps
Sent: Saturday, August 20, 2022 16:49
To: Amps Group <amps@contesting.com>
Subject: [Amps] Commander 2500 toroid
Folks, I’m in need of a Command Tech HF2500 low band toroid. Looks like FT8
got the best of this one. If anyone has one, knows who does, or can rewind one
please let me know. There’s a remote possibility if I take it out I can
possibly try to wind one but this thing got so hot it melted the (Teflon?)
jacket right off the wire. Question is, does the heat destroy the iron core?
Any help appreciated. Thanks, Lou
Sent from the all new AOL app for iOS
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