Thanks to all that offered suggestions. It turns out to be a silly thing as
I thought.
When I pulled the two 200pf doorknobs for 160 tuning and put in a single
500pf
it left a mounting hole that I decided to use the additional doorknob for
the loading
on 160. It turns out that the mounting hole was on the hot side of the
tuning cap - I
was thinking it was on the cold side. Needless to say it really messes up
the output
network. All is well now.
73, Larry W6NWS
----- Original Message -----
From: "Larry" <lknain@nc.rr.com>
To: "Amps" <amps@contesting.com>
Sent: Wednesday, November 17, 2010 8:17 PM
Subject: Re: [Amps] Suggestions - I broke my amp - part 2
> Not that I know of. The amp was working except it needed new parasitic
> suppressors. I
> replaced the suppressors, the plate RFC, and the plate blocking cap. The
> output network
> itself was not touched except that I changed a pair of doorknobs (200pf
> each) with a 500pf
> doorknob that gets switched in parallel with the tuning cap for 160. I
> also added an additional
> 200pf doorknob that gets switched in parallel with the loading cap for
> 160. They look correct
> with an ohmmeter.
>
> I am going over things yet again and reheating solder connections just in
> case I missed something.
>
> 73, Larry W6NWS
> ----- Original Message -----
> From: Dave M
> To: w6nws@arrl.net ; amps@contesting.com
> Sent: Wednesday, November 17, 2010 7:15 PM
> Subject: RE: [Amps] Suggestions - I broke my amp - part 2
>
>
> Possible arc over and short of the tune cap ??
>
>
>
> ......................................................................................................
>
> 73 VE3DV , Dave
>
>
>
>
>
>
> > From: lknain@nc.rr.com
> > To: amps@contesting.com
> > Date: Wed, 17 Nov 2010 18:42:29 -0500
> > Subject: Re: [Amps] Suggestions - I broke my amp - part 2
> >
> > It turns out it doesn't matter about the bandswitch position - same
> result
> > in all positions regardless
> > of the transmitter freq. The bandswitch seems OK by visual inspection
> and
> > with an ohmmeter.
> > I have to wonder where the power is going. No arcing, no noticeable
> heating
> > so far but I
> > don't run it too long since it is obviously not working correctly.
> >
> > 73, Larry W6NWS
> > ----- Original Message -----
> > From: "Gary Schafer" <garyschafer@comcast.net>
> > To: <n8de@thepoint.net>; "'Larry'" <w6nws@arrl.net>; "'Larry'"
> > <lknain@nc.rr.com>
> > Cc: "'Amps'" <amps@contesting.com>
> > Sent: Tuesday, November 16, 2010 10:17 PM
> > Subject: RE: [Amps] Suggestions - I broke my amp - part 2
> >
> >
> > > If the output relay was open there would be a large dip in plate
> current
> > > when the tune control was tuned with drive applied.
> > >
> > > Open bandswitch or switch on the wrong band is most likely. Try
> another
> > > band.
> > >
> > > 73
> > > Gary K4FMX
> > >
> > >> -----Original Message-----
> > >> From: amps-bounces@contesting.com
> [mailto:amps-bounces@contesting.com] On
> > >> Behalf Of n8de@thepoint.net
> > >> Sent: Tuesday, November 16, 2010 7:53 PM
> > >> To: Larry; Larry
> > >> Cc: Amps
> > >> Subject: Re: [Amps] Suggestions - I broke my amp - part 2
> > >>
> > >> One thought:
> > >>
> > >> Have you checked the output relay to see if it makes contact when
> fired?
> > >>
> > >> If the output of the amp wasn't making it to the antenna, the
> symptoms
> > >> you describe would be happening. No RF getting past the relay due to
> > >> the relay NOT closing properly would give no output to your RF
> meter,
> > >> right?
> > >>
> > >> 73
> > >> Don
> > >> N8DE
> > >>
> > >>
> > >> Quoting Larry <lknain@nc.rr.com>:
> > >>
> > >> > A number of you offered suggestions a couple of weeks ago and I
> checked
> > >> those
> > >> > suggestions a couple of times. I have finally got back to trying
> to
> > >> > track down what
> > >> > is probably a silly error on my part that has broken my
> > >> > Clipperton-L. The mods were
> > >> > triggered by the destruction of the original parasitic
> suppressors.
> > >> > The amp was
> > >> > working - just not well in all conditions.
> > >> >
> > >> > I replaced the power supply board (just an upgrade to better
> > >> > supply), replaced the
> > >> > plate RFC to an Ameritron AL-572 RFC along with the parasitic
> > >> > suppressor board,
> > >> > changed the plate bypass cap at the power supply side of the plate
> > >> > RFC to a 0.002uf
> > >> > value, changed the plate blocking cap to 0.002uf, changed the
> > >> > filament RFC to a
> > >> > bigger unit, and changed a couple of doorknobs for 160 (unrelated
> to
> > >> > the original
> > >> > problem of the parasitic suppressors). I haven't gotten to 160
> yet.
> > >> > The current effort
> > >> > is using 40. The current result is still no output
> > >> >
> > >> > 1. There is plate current (as measured by the panel meter) and
> there
> > >> > is plate voltage.
> > >> >
> > >> > 2. I don't have a HV probe but I could measure at the plate
> voltage
> > >> > (at the plate caps)
> > >> > as the voltage was dropping after turning off the power switch and
> > >> > it tracked with the
> > >> > panel meter.
> > >> >
> > >> > 3. The idle current seems OK.
> > >> >
> > >> > 4. The plate current follows keying. The plate current changes as
> it
> > >> > should as the driving
> > >> > power is increased or decreased.
> > >> >
> > >> > 5. Adjusting the output cap controls has no noticeable effect on
> the
> > >> > plate current (no dip
> > >> > etc).
> > >> >
> > >> > 6. Using an ohmmeter there is continuity (short) from the output
> > >> > network side of the plate
> > >> > blocking cap (on the cap lead) to the output connector. From the
> > >> > other side of the
> > >> > plate blocking cap (on the cap lead) to the power supply there is
> > >> > continuity (short).
> > >> > Thinking perhaps the new blocking cap might be bad I replaced it
> > >> > with a pair of 0.001uf
> > >> > in parallel but still have the same result. (I remeasured the
> shorts
> > >> > after replacing the
> > >> > blocking cap.)
> > >> >
> > >> > 7. The output relay is switching as it should. None of the wiring
> to
> > >> > the relay was touched
> > >> > in this mod.
> > >> >
> > >> > It has been a long time since I worked on an amp. I am sure I am
> > >> > overlooking something
> > >> > small and silly. I was hoping one of the gurus here might have a
> > >> > pointer or suggestion of
> > >> > something I might have missed.
> > >> >
> > >> > Thanks
> > >> >
> > >> > 73, Larry W6NWS
> > >> > _______________________________________________
> > >> > Amps mailing list
> > >> > Amps@contesting.com
> > >> > http://lists.contesting.com/mailman/listinfo/amps
> > >> >
> > >>
> > >>
> > >>
> > >> _______________________________________________
> > >> Amps mailing list
> > >> Amps@contesting.com
> > >> http://lists.contesting.com/mailman/listinfo/amps
> > >
> > >
> >
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|