I can't comment specifically on the "F" version, I have never seen it or the
documentation.
I wondered about the same thing Rick, but can only report my findings. As
stated by R.Measures, it probably was the end result of some major glitch
(thinking back, I did have one - while tuning up on 10m, a BIG bang ocurred
causing my XYL to come running from the other end of the house! and a split
anode on one of the tubes (that was the end of my first set), as reported I
never got the second set to work satisfactorily).
The reason for the two decoupling caps, is probably poor RF characteristics
of the electrolytic cap (remember that the design is more than 30 years
old!)
Vy 73 de OZ1PIF, Peter
********** OZ1PIF **************
email: oz1pif(no-spam-filler)@get2net.dk
http://hjem.get2net.dk/oz1pif
Ph. +45 4619 3239
Snailmail:
Peter Frenning
Ternevej 23
DK-4130 Viby Sj.
Denmark
***********************************
----- Original Message -----
From: "R_Davis" <WD8JJA@arrl.net>
To: "H & W Electronics" <info@handwelectronics.com>;
<Fox_Tango@mailman.qth.net>; <amps@contesting.com>
Sent: Tuesday, October 28, 2003 2:51 AM
Subject: Re: [Amps] FL-2100F/B
> Very interesting, Peter,
>
> Actually, the question was proposed by "H & W Electronics" on another
> reflector; I have a 2100B with the similar symptoms, while he asked about
> the 2100F.
>
> The 2100B schematic calls for a 220pF on each grid. If only one went bad,
> wouldn't I see a different response by using only one tube and switching
it
> from one socket to the other?
> What do you think about the disc/electrolytic combination between the
> bias-set resistor and the RF choke? This may be just a filter for the
ripple
> on the half-wave rectified bias, but they are common to both tubes. so if
> one was leaking, wouldn't it pull both grids down by the same amount? I
> can't read my schematic very well, but it looks like they are a 0.01 uF
disc
> to ground in parallel with a 2 uF/25V electrolytic to ground (although the
> parts list calls it a 2.2uF/50V - more likely).
>
> The 2100F is laid out a little different, with a 10uF on the
relay/grid/bias
> board.
>
> All comments appreciated.
>
> Rick, WD8JJA.
>
>
> ----- Original Message -----
> From: "Peter Frenning, OZ1PIF" <oz1pif@get2net.dk>
> To: "R_Davis" <WD8JJA@arrl.net>; "H & W Electronics"
> <info@handwelectronics.com>; <Fox_Tango@mailman.qth.net>;
> <amps@contesting.com>
> Sent: Monday, October 27, 2003 3:32 AM
> Subject: Re: [Amps] FL-2100F
>
>
> > Hi Rick,
> >
> > Check very carefully the two caps tying the grids to ground, I believe
> they
> > are C8-9 220pF in your version.
> > I had exactly the same symptoms in my FL2000B, with a set of new
bottles,
> > and not until I took it completely apart for conversion to a QB4/1100,
did
> I
> > find that one of these caps had blown - split completely open, but
> invisible
> > from the outside!
> >
> > Vy 73 de OZ1PIF, Peter
> >
> > ********** OZ1PIF **************
> > email: oz1pif(no-spam-filler)@get2net.dk
> > http://hjem.get2net.dk/oz1pif
> > Ph. +45 4619 3239
> > Snailmail:
> > Peter Frenning
> > Ternevej 23
> > DK-4130 Viby Sj.
> > Denmark
> > ***********************************
> > ----- Original Message -----
> > From: "R_Davis" <WD8JJA@arrl.net>
> > To: "H & W Electronics" <info@handwelectronics.com>;
> > <Fox_Tango@mailman.qth.net>; <amps@contesting.com>
> > Sent: Monday, October 27, 2003 4:15 AM
> > Subject: [Amps] FL-2100F
> >
> >
> > > Copy to AMPS reflector.
> > >
> > > H & W Electronics <info@handwelectronics.com>:
> > >
> > > Did you get a satisfactory answer to this, yet?
> > >
> > > I have an FL-2100B with similar symptoms.
> > > I used to have normal (~.090) bias, was able to drive it to > 500mils,
> and
> > > it put out 700 - 800 watts peak normally (more if I crowded it). Now
I
> > get
> > > only about 60 mA bias, can only drive it to 250-300 mA, and get 300
> watts
> > > out, at best. Also, driving it real hard, the LOAD control stays at
or
> > near
> > > 0.
> > > Those are my symptoms.
> > >
> > > Possible related causes: One time, I accidentally was tuning into the
> > > internal dummy load of my Dentron MT-3000A which is rated for 200
watts
> > and
> > > is protected by an internal fuse. I popped the fuse, but quit as soon
as
> I
> > > saw the SWR skyrocket.
> > > On another occasion, and I cannot remember if it was before or after,
I
> > > heard a "TINK" from the amp.
> > > Neither time did I notice these symptoms immediately, but it has only
> been
> > a
> > > few months since the blown fuse and the "TINK".
> > >
> > > Is the concensus that the tubes are now soft? Funny thing, I checked
it
> > > with one tube at a time, and with either tube in either socket, I can
> > drive
> > > it to over 200 mA, maybe even 250 with my FT-101E. But I can't get
500
> mA
> > > with both tubes in. HV still looks good @ 2400V, dropping to around
2200
> > > under load. ALC action looks normal, but at only about 300 watts out.
I
> > > haven't cut the ALC line yet to see if it is holding it back. I don't
> > think
> > > it is since I.C. on the exciter looks normal.
> > >
> > > Any suggestions before I by a new set of bottles??
> > >
> > > Rick, WD8JJA.
> > > ----- Original Message -----
> > > From: "H & W Electronics" <info@handwelectronics.com>
> > > To: <Fox_Tango@mailman.qth.net>
> > > Sent: Monday, October 20, 2003 11:29 PM
> > > Subject: [Fox_Tango] FL-2100F
> > >
> > >
> > > > Hi All!
> > > > Anyone ever had low reading on the bias current? This one does
only
> > > > .06 while spec is .09. What gives?
> > > >
> > > > Now, more than ever, QSL.NET is in urgent need of your financial
> > support.
> > > >
> > > > Please help QSL.NET by sending a donation now.
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> >
> >
> >
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