[Amps] Commander 2500 toroid

[k1ttt.dave at gmail.com]

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 at arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: telnet://k1ttt.net:7373


-----Original Message-----
From: Amps <amps-bounces at contesting.com> On Behalf Of gudguyham--- via Amps
Sent: Saturday, August 20, 2022 16:49
To: Amps Group <amps at 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


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