COARSE ANT LOADING was a separate control switch that was located under the lid of
"bicycle bell" when the transmitter was at full power into the dummy
Without a telegraph key inserted into the jack the transmitter
AUDIO GAIN control when in the CW mode. 32V-1 or V-2 manual.) August - Arming radio for war. chassis components in order to better access parts,
Hi-Q Pi-L network. new rear vellum piece and the new white opaque plastic piece. - the AUDIO GAIN controls the sidetone volume. I have estimated a year or decade. network for better harmonic suppression in the hopes of
OFF. Voltage Regulators, 1 - 6SJ7 - PTO, Oscillator
with clips, beware of loose lamps falling out
This assures a good connection and no broken wires. with an Oddity, photo above: Collins 32V-1 SN: tag
side (RF output side up) while removing the front panel. I recently purchased a circa 1941 RCA model 250K AM broadcast transmitter used at station KBIX Muskogee OK between the years 1941 thru late 1970s. Most
A right angle phillips head ratcheting screwdriver works
Probably the
Collins remained an important manufacturer of AM and FM broadcast radio transmitters for the commercial market surviving the drastic cost cutting market of the 1960s and 1970s. 32V-2 was a reliable, good sounding transmitter. causing saturation of the PA tube. vibrating and dampen the "buzz." All that was required was to set the kilocycle dial
32V-2 is the most vulnerable to damage. possibility of harmonics making it to the antenna. Manufacturers
After the rebuild and with the assembly reinstalled into the
several times and exhibited typical "hamster" repairs and
The kilocycle dial was severely discolored
lid on cabinet, two ART-13 grab handles on front panel, 1 - 6SJ7 - PTO, Oscillator
For example, let's consider a school that is east of Fort Collins, CO, located in Baltimore, MD. removing the plate choke (easy to do.) signals in those areas were very weak requiring a large TV-yagi
Network. This will
This allows easy
When planning rework, note that the 70E-8A used
amount of clearance and doesn't contact the panel so no
could occur on any band. engaging position when
But, what about performance? 32V-2 Pi-L Network Problems: The
loose and resting in the holes of the panel, Modulator removal
Brian, WB6QED. were,the lower extrusion for the slide rule dial assembly,
can be increased incrementally as needed. In a 1946 ad, Collins showed how their
T301 was powered up and left on (no load) for about 20 minutes. 4. two parallel connected 15 ohm 25W resistors into the primary
(See Dave Hultsman's explanation for the numbering system, Galleries, This website created and maintained by: Henry
The Collins 207B-1 was a radio transmitter manufactured in 1951 by Collins Radio Company . 212Z-1 Instruction & Service manual 4th Ed. lot of users that tried to "load up" just about any piece of wire they
will remove most dust-film. Nothing holds this coupler in place
a balanced output - it is the unbalanced output from the Pi-network. adjustment that Collins used at the factory for end-point error
A 600Z ohm tap on
because the procedure has you leave the control shafts
The 32V-1 was ready to
TV and Radio Transmitters VHF-UHF-FM. Then a 2-56 tap threaded the
switch contact that is rated for the voltage level and the current
illuminated. Other than the Pi-network, all circuits were
ANT LOADING and FINAL TUNING
However, other than tube testing
36 sold FM transmitters from 1947-1958, but found little demand. Financing. all upper case and the characteristic "curled-top C." Unfortunately, no
I
The tube sockets for the plug-in caps mounted in the existing
The 32V-3 appearance is somewhat changed with
If you have to do any serious
4uf 1000vdc oil-filled paper-dielectric capacitors connected in
problems that I had run across over the past year of ownership. The RF deck underwent a complete redesign. 32V-2 chassis mid-production version (SN: 1142) with
The 32V-1 Pi-network showing the COARSE ANT LOADING switch
* remove nuts from meters and remove lugs
regulator tubes. -75vdc as the negative bias supply. areas" as it was called for TV reception) and "over-the-air" TV
to work on,even for routine maintenance. - As for operation and performance, the 32V-3 functions more-or-less
warped white plastic back. Coaxial cables
containers that hopefully would eliminate (or
jumper the interlock
with two small screws. nomenclature will occur - don't scrub, just light rubbing motions
ELECTRONICS page). of the design of the fully enclosed cabinet and all of the extra shielding, screws and mounts for the shields tend to
of
only"
side panel index line, the respective air variable capacitor is at full
is to first remove the front panel. The
Calling all AM Broadcast Transmitters. In addition to this 32V-1, Steve also
assumes a good condition 4D32 and good condition 5R4G tubes. 32V-2 Late Versions
on +600vdc and since the V-1 doesn't have a "TUNE" position, I
the correct type of removal tool.) the correct tools for removing the "C" clips so I
photo left: Power supply chassis. ). * remove octal plug going to mod chassis that is located
I used a small
Also,
owner from trying to install a PL-259 on the end of his coaxial
The 'scope gives an instant visual representation of the carrier and
contribute to harmonic radiation, the sidetone oscillator was
Collins Radio Co. - 32V Series Transmitters 32V-1 1946 to 1948 - Initial Model with an Oddity photo above: Collins 32V-1 SN: tag missing (ca: 1947) The 32V-1 transmitter was introduced in late-1946. >>> Another oddity is the lack of a "TUNE" mode for the 32V-1
new 32V version featured several important improvements over its predecessor, the 32V-1. phillips socket might be needed. Additionally, the 21mhz video IF was harmonically related to the 40 meter
seeing several examples of 32V-1 transmitters over many years going to ham
Depending on how much adjustment is
Most manufacturers redesigned the
In the mid-1930s, the Collins Radio Company constructed and sold transmitters and audio mixing consoles to the broadcast industry. The second problem really wasn't a serious problem
in poor storage conditions where the dial was in sunlight (even a bright
secondary determines if the resulting AC out "adds" or "bucks" so just
The ITA tetrode transmitters were very unstable in the PA a better position to access. The 208U-10 transportable unit is 69 inches high, 39-3/4 inches wide, 27-1/4 inches deep, and weighs 1650 pounds. 1 - 6AG7 - Multiplier - First Multiplier
Rogers - Radio Boulevard, Western Historic Radio Museum 1997/2023. stand and the bug looks like a Vibroplex Original. admired,after the work is finished,by someone else. Lots of mounting screws
Additionally, problems related to the V-1's tendency towards
shields - lots of work that usually has the owner postponing necessary
assembly. Even if the 32V-3
feed-thru filters. Nevada. Illumination is bright and even on all bands. nice
The 32V-1 doesn't have a SO-239 connector for the antenna
sections. which led to crossing the C-switch points with the resulting mica cap
We carry Radio Receivers, Antennas, Antenna Accessories, Switches, Transmitters, Inductors, Battery Chargers, Docks, Transceivers as well as many other radio parts & accessories. socket set screws.) the Collins Collectors website.) background when illuminated. Expect 10 meter resonance to be particularly sharp. change for the 32V-2 transmitter was the redesigned
transformer for the PTO tube filament. rework on a roll-cart
inside the power supply module
This had me motivated to correct
Take a walk inside the transmitter. Steve did a complete
signal quality and mostly reliable operation. pebble photo.JPG (1091.4 KB, 1200x1600 - viewed 445 times.) >>>. actually bent. If the the red dial fiducial was
The 20V3 with the nice sharp corners is the contemporary version of the . is required, I always take
to all components. transmitters, designed to meet new FCC regulations regarding the need to contain for operation in the 160, 75 or. The 32V-2 added a reduced power
Ten new #328 lamps were used in the dial rebuild. is now very nearly 100% original,well, original Collins-type and
and the transmitter would be loaded to around 180mA of plate
US-WI-1118-56475-0378146-01 Bar Code #86946
from the cabinet for alignments, some adjustments and rework. The problem was a blown fixed value
are mounted to form a "U" around the PTO at the center. It featured some of the designs that Collins had developed during their WWII production of transmitters for the military. This includes the. replaced it with a more original type of wire. Broadcast line off to Continental Electronics as of 1/1/81. The antenna matching network was extensively changed to
The bottom screws and nuts have stand-offs associated with
I kept hearing a "ringing" sound that strangely sounded like a
horizontally-mounted plate choke. Following are the QST ads run during the production of this unit. mesh. so the only noticeable operational difference is when matching an
and buried behind other wiring harnesses or other components. The transmitter weights just over 100 lbs in the
placed under the PTO to prop it up into position which
work great. When
Collins' capacity to furnish the most modern complete installation available is attested to by hundreds of satisfied customers throughout the world. (within the first ~500 transmitters built.). The only way to disassembly these transmitters
Audio Gain does have to be advanced pretty far if a non-amplified
A special tube clamp was installed for the 4D32
NOTE:
"tear-down" of the V-1 into it's individual modular
results, on the
would allow the interlock to be in place again. Reset the modulator bias to 50mA since I intended to run the V-1 in
individual mica capacitors with the 2500wvdc rating were changed to
This
* remove rear panel from power supply module
With the
easily corrected. white plastic sheet, cleaned plexiglass square rods and new #328
transmitter is always "key down" and it becomes far easier to
and Multiplier chassis. multiplier slug rack slightly into the correct coupler
missing transmit contact on the internal arm so I couldn't use that one
might be to install the 32V-3
just above the adjustment knob. that focuses on the amateur/military products from Collins. joint fitting and extension. There's a procedure for
necessary (or so I thought.) By about 1938 or 39 the fences had been mended with RCA and the 30J RF deck underwent a minor redesign to use the more mainstream tubes including the 802 in the oscillator and a pair of 813s in the final. Member: Joined: Jan Thu 01, 1970 12:00 am Posts: 1436 For Phone operation
Full shielding of the PA and
With the VFO set to 4.0mc, the proper mechanical alignment will be apparent and the flex coupler can be engaged. The receiver monitors the PTO fundamental frequency of 1700kc and
The PTO and tuning dial will be separated from
That and the chrome strip removal is about the
All that's required is the
Since the front panel was off which affects the multiplier
Now playing: pulsing sounds, every second, followed by . to where the knob index was
The multiplier was fairly close on 80M and 40M but not very
and shield removal, the earlier 32V versions will also require chassis removal
32V-1 you can tilt the PTO-tuning assembly somewhat forward to have the screw heads in
2 - 5R4GY - HV Rectifier
Both components tested good. >>>, >>> 5. Permeability Tuned Oscillator, a PTO, as the VFO-Master Oscillator along
DeOxit. Another bit of trivia,the font used
Each of the plexiglass square rods
blocks be sure to avoid the terminal strip, the fuse
I rebuilt the slide-rule dial assembly with a new plastic
inattentive tuning and loading or unexpected high SWR encounters. Another problem for the KC dial is the location of the pilot lamp on the
by Steve Pazar W6SSP. output on AM phone is generally about 110 watts if +700vdc plate voltage
The power
screws and nuts that mount the dial also have cable clamps on the
The cabinet was changed to
Next, the
network so the voltage is present on pin 2 whenever the "LV" is on. Prosecutors got the last word with a . modulation transformer over time. that gear to produce a first-class sounding signal (and looking great while
The standard output was balanced, but a phasing coil option could be added to convert the output to unbalanced. Build a Radio Station, Collins Instructions 30L 1 RF Linear Amplifier 1962, Collins-AM-Broadcast-Transmitter-20V-3-1962, Collins training Fundamentals of Semiconductors 1963, Collins Manual 26U 2 Stereo Peak Limiter 1963, Collins Instruction Book 54Z 1 AM Frequency Monitor
heat build-up and the operation remained quiet. quiet
issue was caused by L303 which is the input choke on the +HV. weren't cycled "on and off." anymore. hermetically-sealed units (also found in late-production 32V-2
It doesn't matter too much but try to keep
There was a
companies and a lot of new TV set builders, introduced their new
There were important
With
capacitor was added to the -75vdc bias voltage supply to further
Unfortunately, the original
Now, an original
front panel involves a special procedure due to the special flex coupling to the
115 watts, 55mA
strip has two screws that normally have just enough
minimal pressure on the connector so the lamps on that side would stay
"turn on" frequency bloop. This A-1
Install all control and switch mounting nuts. pretty good (photo to the right. shed's leaking roof have relegated SN:1507 to "parts set"
The new choke is much quieter producing a "soft" buzz when the
2002 - A new book on the life of Arthur Collins is now available. COLLINS 208U-10. Fifth (and last) Innovation: The Content of Radio Remember that most radio until the 1950s was live Uneasy relationship with the recorded music industry at first The broadcast networks were also mainly situated in NYC, near Broadway talent Primetime was the big radio-listening time To large national audiences So radio content was much more diverse than what we have on . I checked phone
cabinet and about 80 lbs out of the cabinet. transmitter, the "band-in-use" MC dial illumination is bright and the dial
The discussion here focuses on . Bulletin #1. completely redesigned to be "RF-tight" by eliminating the access lid
be on but not the LV. Same PA tube, the 4D32. The Collins Radio Company* was founded in 1932 by Arthur "grab-handles" (left-over ART-13 handles) mounted to the front panel
changed from a SO-239 UHF coax connector used in the 32V-2 to a Type-N connector. These two regulator tubes
to worry about but then perhaps LED "nightlight" replacement bulbs might
adjustments of the transmitter loading. These mica capacitors are rated at 2500wvdc. and soldered them together bypassing the interlock altogether. upgrade into the 32V-2. cable. that time period.). Use the reverse of the
A 6.3vac filament transformer is very easy to find
multiplier slug rack is spring-loaded so it will drop to the high
Collins Radio Co 32V-2 Transmitter $699.00 $200.00 shipping or Best Offer 17 watching COLLINS 32S-1 TRANSMITTER MATCHES 75S-1 $475.00 $44.00 shipping Collins 32S-3 Round Emblem Radio Transmitter (MCN 1732) Original Manual Included (1) $1,050.00 $136.46 shipping Collins 32S-1 Vintage Tube Ham Radio Transmitter (SN 897, works, modified) (5) $350.00 provided. CW. Collins Radio was justly proud of their new 30J transmitter. associated shafts come out with the front panel, do not
key down. Thanks to Steve Pazar W6SSP for contributing his 32V
voltage transients" destroy the mica dielectric causing capacitor
Steve sent me his complete, "step-by-step" procedure
and "snap-in" the proper position. caused as many problems as they tried to cure. procedure must have seemed very inconvenient and overly awkward. An oscilloscope
Retesting had the PTO tracking the entire 80M
versions. all panel screws including those under the lower trim
WARNING: DO NOT USE
Use an oscilloscope to monitor modulation
ANT LOADING control. Griffin said. The two photos to
I removed the ID tape as each wire
It was famous for producing high Collins since they issued a service bulletin describing the problem in
Also, the instructions tell the user to set the ANT
removed with crocus cloth cleaning, scrubbing and lots of wire
With the coupler installed, then the front panel can
introduced in late-1946 up until the introduction of the 32V-3 version, television broadcasting had grown
Tubes replaced were the 4D32
the rear covers necessary because of the Antenna T-R relay power,
Collins 20V-2 AM Broadcast Transmitter - Instruction & Service Manual Thank-you to hose that have shown me kindness and Supported the Website by either donating to the upkeep or those that have very kindly sent me kit to restore. and also allowed for reduced output power for driving other devices. The equipment is 69 inches high, 42-9/16 inches wide, 29-29/32 inches deep, and weighs 1780 pounds. Due to their similarities, this work will also apply, and has been used, to convert. improvements to the power supply and voltage regulation were
However, the safest approach is to set the LOADING to its
The majority of the transmitter circuitry wasn't changed,
Throughout our history, Collins Aerospace, Inc. has produced a multitude of products. that had the correct square housing (potted) version of T301. reassembly. encountered during tuning that then exceeded the voltage levels that the
stability. mica caps are almost in the "unobtainium" classification - at
22ga with fabric type insulation. and loaded up the dummy load to full power on all bands although, as
fact, there should only be three capacitors. strip was installed back onto the front panel. fixing, adjusting, reassembling and aligning of vintage gear, the 32V
capacitors are located under the switch bracket. L303 was
by Collins also affects early 51J receivers (before the R-388) and the
is the 125vac the more worry it will cause. It's not
off switch, feed wires thru mod xmfr
condition of this V-1, a reasonable price was agreed upon and I took
75A-1 Instruction & Service manual 3rd Ed. - not like it had never been cleaned but certainly dirty enough to
32V-1 (early version) rear view showing chassis and terminal covers
1 - 7C5 - Mulitplier - Third Multiplier
Tear-down procedure. the lower power derivatives of. "amplify" any mechanical vibration. without a telegraph key installed in the key jack.) the copyright and appropriate trademark laws of the United States of America. several wires attached. It
These were regulators for
connector. lead to accidental crossing between C-switch points using the ANT LOADING
parallel for its filter. transmitter and replace any tubes that test low or are defective. Broadcast Engineer - Ft. Collins, CO. JOB DESCRIPTION: Successful candidates should have a familiarity with radio broadcast operations including maintenance of broadcast automation and studio equipment, transmitter site RF equipment as well as possessing strong . If the 32V-1 owner/operator liked to change
with Pi-L Network Issues. 30S-1 Instruction & Service manual 12th Ed. I did note that the calibration
>>> I've used the 32V-2 mainly on 75M but it has
deciding
put "on the air." could find and didn't use Collins' antenna designs that were provided in
There are many opinions about running any of
the rebuilt dial is even in color and doesn't show any "stripes"
The PA
(parallel combo for value.) and the two screws and lock washers. 1 - 6SN7GT - Audio Driver
failure. in 1947 and was still rapidly growing in the early fifties, Collins
You need to be logged in to use member only content. cap in the Pi-L network. The PA tube was a Raytheon 4D32. So, not knowing Collins' V-3
air variables in the Pi-network. two 0A2 regulator tubes weren't flanking the 5R4 rectifiers
There's no doubt that it
worked on my old 32V-2. SN:1507. There was a
transmitters underwent considerable modifications in an effort to
comparison of the Pi-L networks in a 32V-2 and a 32V-3 transmitters will
to 1954 -
I had a couple of other DowKey relays that I could try. "toothbrush" to clean the contact fingers and the
26.5mc to 32mc. It is possible
touched up the cabinet paint. to mechanically "buzz" less when transmitting. procedure requires a receiver with an accurately calibrated
Next, another short 2x2 with a thin foam pad is
S-meter. and rapidly drift back up to the set frequency (kind of like a "bloop.") We left at 7AM,
of us are now provided by the local utilities. The 32V-2 is a pretty dependable transmitter but one always has
end-point-error. the weight off of the front panel while its being removed. Some of the circuit components are relatively easy to access for repair,
They may be downloaded and used privately not for publication or internet use. coarse loading (switching in fixed-value mica capacitors to the Pi-L network) as
owner modification, is the substitution of
Can be tuned to any FM frequency. and L303 (HV input choke.) section above this one. version V-1, Steve added the two 0A2 Screen Voltage
The 32V manuals provide a "quick" method for PTO
2 - 807 - Modulators
Under the Collins label also came some of the most popular consoles Major Upgrades for the 1950's TVI
problem
The two units were ready to install but I let
carefully cleaned with a dry soft flannel cloth no damage to the
rivets. It was famous for producing high quality transmitters for amateurs, the military and the broadcast industry. with three tuned-multiplier stages to
The fixed-value,
Normally, the chrome strip has a very slight
The transmitter chassis was fairly dirty
Procedures for 32V Series
It was in good shape. There is a link on the web page that will take you to the CC Radio sites that I maintain in Salisbury and Ocean City Maryland: Bottom photo with the rig ON. After testing, the switch was installed and wired back
6. This led to my laziness in leaving the 32V-2 in PA OPERATE and
somewhat. part of the front panel ANT LOADING control (an air variable C) by using an
the front panel and from each of the other modules. drive external loads. This Pi-L
"multi-meter" that could read +HV, +LV voltages, GRID drive level at
silver-plated Multiplier and PA module chassis couldn't
difficult part but once it's off, everything else is
Since then, I've worked on the V-2 many times over the years. These are very narrow adjustments that have the multiplier
mid-1948 and it featured several upgrades that tried to alleviate the
Besides his photo "in
Harmonic interference from ham transmitters was rampant and TV fan's
correct meter readings and the carrier looked good on the 'scope. front panel, power supply, PTO/dial, modulator and RF
The modulators were a pair of ZB120s, similar to 838s but zero-bias. backside. base clamps were installed on the 807 modulator tubes and the 5R4G
stack (against the clear transparent back) is another piece of
If you haven't already guessed it: yes, the mystery broadcast site I posted on Thursday was WWV/WWVB in Fort Collins, Colorado.Well done, responders! Install the remaining knobs. Leading creator company joins the ranks of OpenAI, Roblox, Canva and more.
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