[ForSale-Swap] For Sale - Partially Completed 2 Meter Kilowatt Amp & Pwr Supply

[Bob Kocisko]

Hello:

This message pertains to a partially completed homebrew 2m kilowatt pwr amp
(PA) + pwr supply (PS) that I hv for sale.  In the May 1975 QST, W9OJI
described a 2 meter version of the K2RIW amp using 2 x 4CX250B's in parallel
with a 0.25 WL stripline for the anode & a 0.5 WL stripline for the grid
ckts.  I purchased this partially completed project fm a ham with the intent
of using much of the RF deck & many parts of the HV, screen & bias supplies
but rebuilding them so they will look vy professional in my 6 foot rack
cabinet.  I intended to re-build a heavy duty HV pwr supply (using the big &
heavy xfmr included), & screen, bias & filament supplies that would pwr this
tetrode PA on 2m + a 70cm tetrode PA.  I purchased this partially completed
PA & PS for $300 abt 4 years ago strictly for the parts & am offering it in
the same condition as when I purchased it for the same $300.  This will
probably need to be a pick-up only due to the size & weight.  Based on the
value of the parts alone, I think this price represents xlnt value.  I hv
several buyers for a similar partially completed 70cm PA + PS that is being
sold for $350.  So, if you're interested in this project & hv the ability &
desire to complete it, pse read on for a detailed description.  Otherwise,
tnx for reading & go ahead & delete this long message now.

73,
Bob, K6PF
DM13ar

Detailed information for those of you who are interested follows.

WHAT IS INCLUDED:

The RF deck consists of two 17x7x3" aluminum chassis mounted back to back.
The 2 tube sockets are part of an assembled unit which was removed fm some
other equipment.  It is mounted along with 2 x 4CX250B's.  The 0.25 WL brass
stripline plate circuit & plate blocking cap are mfg'd & installed.  The
plate tuning vane (cap) is also mfg'd & mounted with a large venier & knob
on the exterior of the chassis.  The RFC is wound but not installed.  The
output coupling probe has not been made yet & the output coaxial connector &
HV connector & feedthru cap need to be installed.  The 0.5 WL brass
stripline for the grid ckt has bn mfg'd & installed & attached to a tuning
cap.  The capacitive input probe needs to be mfg'd & the tube sockets need
to be wired up.  THe input coaxial connector, RFC & feedthru cap all need to
be installed yet.  I would estimate that the RF deck is abt 60 to 65%
completed.  Agn, the hard part has bn done.  A blower was not included but
will be needed & the airflow system will need to be completed.  I think
attaching this RF deck to a rack mount panel would add a nice touch & any
extra holes in the chassis can be plugged up.

A copy of the May 1975 QST article is included along with another article by
W2GN in October 1977 which described another version of the K2RIW PA for 2m.
That article included a pwr supply schematic.

There is a separate 17x6x3 chassis & cover plate that has 3 meters mounted
on it.  One is 0-6V & labelled filaments, another meter is 0-1ma. for grid
current & the third meter is a 0-50ma. for screen current.  There are
connectors on the rear of the chassis & some interconnecting cables.  If the
RF deck is rack mounted, I think these 3 meters could all neatly be mounted
on the same panel.

The pwr supplies are mounted on a 17x13x3" chassis attached to a 12" rack
panel.  On the panel are 3 additional meters labelled 0-2.5KV plate voltage,
0-500ma. plate current & 0-10v filament voltage.  Thr are also 2 toggle
switches (one is on/off & one is unlabeled), a rheostat to adjust the
filament voltage & a pot to adjust the grid bias.  There is another pot
unlabeled & not connected to anything.  Mounted on top of this chassis are
the HV diodes, HV electrolytic caps, HV metering ckt, screen supply & 2
relays (one is a time delay).  Another hvy duty relay & small xfmr(bias
supply?) are located underneath the chassis.  I never traced this ckt out
since I never intended to use this pwr supply as constructed. My intent was
to use it as an xlnt & inexpensive source of parts to rebuild it the way I
wanted.  Potentially, all of the pwr supplies are completed but I hv no idea
whether they work properly or not.

An old 36"Hx20.5"Wx15"D standard rack cabinet on castors is included.  It
needs paint & does not hv a rear door.  A huge plate xfmr (14"Lx9"Wx7"H) is
mounted on the bottom of the rack cabinet.  It probably weights 75-100 lbs.
This xfmr is labeled 230 VAC primary & 2260V secondary @ 2.1 KVA (almost 1
amp).  There are some interconnecting cables included.  There are 2 of old
pieces of aluminum with various holes that serve as panels to fill up the
space on the front of the rack cabinet.

All of the above is being offered for $300 on a pickup only basis.  I will
sell it without the rack cabinet for $265 since I hv someone that is
interested in the cabinet.

I do hv a couple of optional item I can sell if someone is interested.  I
was going to build a vy well regulated HVPS using choke input filtering.  I
purchased the following additional parts for the HVPS & will sell them for
what I paid.  THey include: 2 separate 35uf, 4KV oil filled caps that look
brand new ($35 each) + a used swinging choke (5-30 Hy, 750-75 ma., 10KV
test) for $40.  The choke also is vy heavy.  So, if interested, I will
include these 3 additional HVPS items for an additional $110 but they are an
option.  I won't sell them separately unless the PA & PS sell first & the
buyer doesn't hv an interest in these optional items.  I also was thinking
of using 2 x 4CX350A's instead of the 4CX250B's.  WOuld get a little higher
pwr out with higher anode voltage.  Also, the 4CX250R's may be a btr choice
than the 4CX250B's.  I may hv 2 or 3 of these tubes available for sale if
interested.

I hv 9 photos (.jpgs) scanned into my computer & can email them to anyone
interested.

Pse let me know if you hv any interest.  Agn, if you got this far, many tnx
for reading this message.

73,
Bob, K6PF
DM13ar