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Re: [Amps] bandswitch repaired (photos)...now plate choke

To: Kevin Normoyle <knormoyle@comcast.net>
Subject: Re: [Amps] bandswitch repaired (photos)...now plate choke
From: Gary Schafer <garyschafer@comcast.net>
Reply-to: garyschafer@comcast.net
Date: Wed, 09 Mar 2005 11:08:32 -0500
List-post: <mailto:amps@contesting.com>
Fantastic pictures Kevin! Thanks much for taking the time to send them. 
They are very handy in seeing where everything goes.

My whole tank circuit had been disassembled and removed. Taps were moved 
around etc.
The pictures are a big help.

Looks like you did a nice job on repairing the switch too.

73
Gary  K4FMX

Kevin Normoyle wrote:
> Gary S. had asked for internal photos of a fl2100b he was repairing, so 
> I uploaded some to msn.
> (I was taking snaps to remember where everything goes)
> http://groups.msn.com/yaesurotatorphotos/yaesufl2100b.msnw
> 
> Just going to reference some bandswitch shots here.
> 
> I was dreading the bandswitch repair, but once you accept the idea
> that you have to take the whole thing out to do a good job, then
> it's not too bad.
> 
> Tools used: variable speed drill with sharp bit, dremel tool (thin 
> cutting wheel),
> brass 2-56x3/8 pan head machine screws and nuts (cut off excess length
> when done). Center punch was useful brace. (put right-sized one in rivet 
> hole on other side while
> drilling to provide steady back pressure against drilll)
> 
> There was a prior set of repairs that was pretty bad. Copper tape bent 
> around
> the ceramic wafer. See right side, middle wafer
> http://groups.msn.com/yaesurotatorphotos/yaesufl2100b.msnw?action=ShowPhoto&PhotoID=31
> 
> (it's a yaesu FL2100-B not a rotator...url was created for something 
> else originally)
> 
> Same photo you can see the 10 meter blown switch position. Lower right. 
> You can also
> see where the metal strip to the tank was blown before and repaired with 
> a soldered
> on wire instead of strip.
> 
> One thing that was interesting to me. Each position on the wafer has 4 
> wipes.
> Two on top and two on bottom. When I examined the ones that weren't 
> blown, not
> all wipes were making contact. I replaced any that seemed iffy . Was 
> thinking that
> any time you have smaller number of wipes working, you're stressing things.
> 
> Got replacement contacts from these wafers:
> http://groups.msn.com/yaesurotatorphotos/yaesufl2100b.msnw?action=ShowPhoto&PhotoID=48
> 
> Close ups of blown contacts (two top middle)
> http://groups.msn.com/yaesurotatorphotos/yaesufl2100b.msnw?action=ShowPhoto&PhotoID=50
> http://groups.msn.com/yaesurotatorphotos/yaesufl2100b.msnw?action=ShowPhoto&PhotoID=51
> 
> After repair
> http://groups.msn.com/yaesurotatorphotos/yaesufl2100b.msnw?action=ShowPhoto&PhotoID=52
> http://groups.msn.com/yaesurotatorphotos/yaesufl2100b.msnw?action=ShowPhoto&PhotoID=53
> 
> Next:  I know I should rewind this burnt plate choke.
> http://groups.msn.com/yaesurotatorphotos/yaesufl2100b.msnw?action=ShowPhoto&PhotoID=37
> 
> I measured about 64 turns/inch? That would make it 27 awg wire? As 
> anyone rewound
> a FL2100B choke? is it 27 awg or ???
> 
> Should I just mark the form and wind exactly as there already. (gaps and 
> all).
> I have a dip meter to check resonances afterwards.
> 
> I see some people saying that the gaps in the choke coil doesn't help 
> change resonances,
> 
> But then some people said that having the burning in specific places in 
> the coil, would likely
> point to specific resonances (vhf or in-band hf). Looking at the burn 
> patterns in the photo,
> it would seem like the gaps did have an effect?
> 
> Thanks,
> -Kevin
> 
> 
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