*Circa August 13, 2005
Today in the middle of a FB QSO with K1MVP the plate blocking capacitor in my 32V crapped out.
This was evidenced by an immediate loss of RF, a loud hum and the telltale pegged plate current meter. Even my trusty old buzzard RF indictor, a large neon bulb JS lashed onto to my balanced feedline terminals, showed no glowage, a very bad sign. When something like this happens out of the blue, a thousand thoughts run through your mind. Is it the final tube, did I inadvertently hit some knob, did the modulator transformer give up the ghost? I quickly unkeyed the transmitter thinking my antenna relay had stuck, as Dowkeys sometimes do. A check of the relay showed that all was intact and the fault must lie elsewhere. Switching between bands or from Fone to CW had no effect, still a pegged plate meter. I considered that something may have happened to my antenna or feedline, but transmitting into the dummy load brought the same result.
I should mention that this was my Elmer’s, W2UJR – now a Silent Key, former transmitter, so the thought of some major failure made my heart sink. When I obtained the unit from Dick’s estate, I had brought it back to life by replacing a stubborn failed screen bypass capacitor on the 4D32 final tube. Since that time it had run flawlessly, despite the somewhat troublesome reputation of the 32V series. The unit had followed me from Buffalo when I moved to Maine and had become my backup 75 meter transmitter at the office. Rumor had it that Dick only ran it on CW as he did not care for the lack of civility on 75 meter Fone.
Ironically I had just been on the telephone earlier in the day speaking to my friend and fellow Collins enthusiast, Bill K2LNU. Bill shared that, after he had spent countless hours working on them, he was now seriously considering selling some of his Collins 32V transmitters because they were such a project to service. With that cheery thought in mind it was out of the cabinet with the 110 lb transmitter, an exercise which had become an all too common event.
I say common as for most of the proceeding week I had been working on a new acquisition to the W1UJR hamshack. A exceptionally recalcitrant Collins 32V3 which displayed a most troubling linearity fault with the Permeability Tuned Oscillator (PTO). It was only after multiple attempts to diligently adjust the linearity, as specified in the service manual, each involving a trip in and then out of the cabinet, that I discovered that the linearity simply could not be restored to the 50 year old PTO. A returned call from Collins guru Howard Mills W3HM confirmed this and I was informed that some years back Dallas Langford had discovered that the ferrite compound used by Collins in the PTO changed its molecular structure with time. So it seems that unlike wine, ferrite does not improve with age, hence the PTO would no longer track properly. As the PTO was a relatively recent invention at the time, Collins had no way of knowing of this during the initial design of the 32V series. Indeed its doubtful they anticipated their handiwork would still be in used half a century later, so no provision was included in the PTO design to compensate for the ferrite change. Anyway, back to our story.
With my failed 32V on the bench I did a quick check of the mica capacitors used in the output loading network. In the 32V series these capacitors are always suspect and have a high failure rate, especially when used with non-resonant antennas. Still, each of the mica loading capacitors checked fine with the DVM, not a fault among them. This meant that I had to dig digger, or in other words this going to take some time. The next step was to remove the plate connector from the top of 4D32 final tube and see what happened with the plate current. I suspected that the tube had perhaps experienced some catastrophic internal failure. Yet again I was stymied, the tube tested out fine, and I still found pegged plate current with the tube plate capacitor removed.
Curiosity got the better of me and I then removed the tube completely from the socket and applied plate current, same result, pegged plate meter. Since the final tube was entirely out of circuit and I still had excessive plate current, as a quick test I removed the coax connector from the rear of the transmitter, Eureka, plate current was now at zero. I now knew that a fault existed in the output network, but where? The 32V series is one of the most tightly packed and difficult transmitters which I have worked on. Despite Collins excellent manuals and documentation, service on these units requires both a great deal of patience and dexterity.
At that very moment I was on the air with Larry NE1S, yes, multitasking. Carrying out a QSO and checking for plate voltage may not be the wisest course if one wants to enjoy a long life. However, in this case it had a payoff. I described the fault to him and explained my findings. Larry confidently asserted that, given my symptoms, it could only be one thing, a failed plate blocking capacitor. With the transmitter keyed, I checked for plate voltage at the RF connector, 890 volts! Sure enough, the plate blocking capacitor was allowing full plate voltage to show up on the output of the antenna! Instead of blocking the plate DC, it was in fact conducting it! Not exactly a safe thing, in fact it was downright dangerous. If I had not had the tuner in line, full plate voltage would be applied to the antenna feedline and leads, ready to zap some unsuspecting passerby. So with that discovery, the next logical step was to unsolder one lead of the plate blocking capacitor. A resistance check showed that my plate blocking capacitor was now a resistor, reading about 23 ohms on the trusty Fluke meter.
The capacitor in question is one of the older square mica capacitors that you see in transmitter output networks, with two mounting holes and solder tabs on the end. This capacitor in particular was rated at 2500 working volts and 5000 test with a value of .001. It displayed no visual sign of failure, no burn marks, case swelling or discoloration. For all intents it looked like a good capacitor, in fact it looked new.
As I mentioned before, the 32Vs are a real challenge to service.
If you have ever had the joy of replacing the plate blocking capacitor in a 32V, heck if you have done any service at all on these 32V series rigs at all, you know what a project this was. A quick check of the spare parts bin yielded the needed capacitor, those $5 coffee cans of parts dug out from under tables at hamfests sure do pay off.
However, finding the capacitor was the simple part. It took me nearly 90 minutes to remove two screws and solder connections on the failed capacitor and install the replacement. The Collins design team had conveniently located the plate blocking capacitor about 3/8 of an inch from a large wound loading coil. Since access to the Phillips head screws which retained the plate capacitor was simply not possible with a screwdriver, I had to settle for turning each screw 1/8 of a turn at a time with a pair of needle nose pliers. So to say things are tight inside the 32V is a major understatement.
Curiosity and abundant spare time got the better of me and I decided to open the defective capacitor up for an examination. After all, things that zorch out are often pretty interesting to look at. By examining the exterior of the capacitor I could see a manufacturing molding line around the upper edge of the case.
Using a bench grinder, I carefully ground away the edges of the case, removing the bonding joint of the upper and lower sections. A small chisel was then used to split the case halves open for a visual inspection. It was quickly apparent what had failed on the capacitor. The center section of the mica had been carbonized from end to end, essentially creating a carbon composition resistor. No wonder at all that I measured 23 ohms of resistance across what was once a capacitor.
So, can those more knowledgeable than I, which is probably a good number of you out there, offer up an explanation why this occurred? Operating plate current was normal, perhaps a tad conservative before the failure as this is my Elmer�s former TX and I run her lightly.
Did the 50 years finally catch up with the capacitor, or did the Zorch Gods just decide it was time? Are there other causes for this? If so I’d like correct them so I don’t have to replace another.
It had been talked about for months, and now the day was here. I found myself in a rented cargo van, with only 3 hours of sleep, at 4:15AM, headed off to the Rochester, NY hamfest. A Collins KW-1, URT-368 transmitter and a heavy-duty generator strapped securely in the rear.
Let me backtrack. Last August, Tom W2KBW and I had been discussing the merits of running an AM Special Event Station at the Greater Buffalo, NY Hamfest. Consisting of my trusty T-368/R390A combo, it was a smashing success, and stirred a great deal of local interest in AM and vintage gear in general. It was only natural for Tom and I to decide to see if we could make lighting strike twice. So we planned to offer the same station line-up at one of the largest hamfests in the Northeast, Rochester, NY held June 4-6.
It was not all that easy however. An early call placed to the hamfest director offered us free space, but inside the Dome. For those who have never attended Rochester, the Dome stadium is a rather imposing structure of steel and concrete, not something that radiates RF very well. Thanks to the efforts of Paul WB3VJB, this matter was dealt with, and we were cleared, and even encouraged to operate outside.
Our plan had called for using the T-368 and R390A in the back of a rented cargo van, for shelter and ease of setup. The T-3 would have been fun, but unbeknownst to me, something bigger and better was an about to happen. The weekend before the hamfest, I was in Syracuse visiting with Tim WA1HLR while he converted a 50KW transmitter for use on the shortwave bands. Tim skills had been hard at work bringing a Collins KW-1 back to life for an owner in New England. I had often admired the transmitter on previous visits. This time however, I did more than admire. The devious gears clicked and whirled in my brain, and before I could think about it I found myself asking “Hey Tim, what about bringing the KW-1 out to Rochester?” Before Tim could say “No”, I was offering a solution to every possible rejection, “Yes, I would pick the receiver up at the shop”, “The hamfest would provide a great sales venue”, “It would be safe and secure in the van”, and yes, a free dinner would be proffered!
And now, here I was, with both the T-3 and the KW-1 on my way to the hamfest. Tim had done a remarkable job of “strapping down” the unit to operate on the weak 120 volt service the site offered. RF output was a fraction of the true power of the beast, at 250 watts. Tim’s magic worked well, and those 250 watts were more than enough to be heard throughout the east cost, and into the Midwest.
Station operation commenced at 10:00AM Friday June 4. The layout consisted of a KW-1, a R390A receiver, RCA BC-7 Broadcast Board, Symetrix 528e Voice Processor. The antenna was an 80-meter dipole feed with balanced line.
I had brought the URT-368 along as a backup transmitter, but it was unneeded. The KW-1 functioned flawlessly throughout the two-day event; in fact the entire station suffered no problems whatsoever! (Not bad considering it was operated near non-stop 10 hours a day in 80+ degree heat!) The only problem we did experience was RF getting back into the audio when we first used the RCA board. Tim quickly cured this by grounding the truck, turning the entire structure into a Faraday shield!
We had a great site, not the one that I had originally picked, but in retrospect it was actually better. The station was located on what came to be called the “grassy knoll” directly in front of the Dome building. Aside from having a higher elevation that the proposed site, two power poles and a tree provided ideal antenna supports. The AMI (Amplitude Modulation Incorporated) banner was attached to the antenna, and fluttered high above the station, visible through the fest.
The station was graced with some special visitors’ early Saturday afternoon; Kay Cragie and Bernie Fuller, Atlantic division directors from the ARRL stopped by for a photo op. Of course the AWA contingent was present as well, Bob W2ZM, Mike W2ZE, and Manny stopped by and joined in the festivities.
We did not have a sign in log, but I would estimate that well over 250 people stopped by to check out the station, and perhaps 50 or so of those were actually drafted to become operators. The station crew was very friendly, inviting anyone into the van to view the layout. We were even able to persuade a couple of fellow hams XYLs to grace the airwaves.
Watching passersby over the two day event, I would see them walk by, do a double take at the sight of the KW-1 on the rear of the truck. Then their face would break out with a large smile, and they would walk up to the station. Tom W2KBW had provided a large monitor speaker, and those gathered outside could hear the melodious tones of AM quite clearly. It was a common sight to see 15-20 people huddled around the station speaker, listing to those on the air holding forth. It was especially interesting to hear the stories from the old timers who had owned or operated a KW-1 at sometime in the past. I simply could not think of a more pleasant way to spend a weekend.
Although the event was most enjoyable, we had another agenda to fulfill that of promoting AM to the “great unwashed”. So often we hear comments that AM equates to Ancient Modulation, wastes band space, is technologically backward, offensive and even boring. We know that nothing could be further from the truth! Not one person that stopped by had anyone but praise for the operation, and for AM. Indeed, I heard more than one ham mention that he planned to dust off his old gear on join us on the air! And those simple words made the entire effort worthwhile.
We broke camp about 5:30PM on Saturday, having filled near 4 pages in the log with AM contacts, making many new friends, and enjoying old ones.
More information, along with copies of the log, audio clips and photos are available at the Buffalo AM website, http://hamgate1.sunyerie.edu/~buffaloam.
Many thanks to those who helped throughout the event, Tim WA1HLR, Tom W2KBW, Bill K2LNU, “Marathon Man’ Russ WB3FAU, and the numerous operators who provided some of the most enjoyable QSOs of my amateur experience.
This is the rig which formally belonged to Bill Orr W6SAI, the well known author and a former editor of the “West Coast Radio Handbook”.
Born May 27, 1924, John enjoyed a very full life, as member of the US Army during the occupation of Japan, as a petroleum geologist, traveling throughout the work, as a private pilot who had owned several plans over his lifetime – holding an instrument rating, a most skilled gunsmith and nationally ranked pistol champion, and finally as a ham, with a life long interest and love of radio. It is in the radio context that many of us many have encountered John, and his creations. He was both well known and very well regarded with the vintage radio community, perhaps best remembered for his wonderful home-brew rigs, often built on cherry wood.
He was also an amazingly generous man, happy to answer any technical question, and frequently giving out gear to others, with the only request that they use it on the air. I was recipient of John’s kindness, with the gift of the W2ER rig, a transmitter that John built some years back for Marshall W2ER SK.
I had the privilege of finishing up the Linc Cundell Contest report for John during his illness. While reviewing the logs, it became quite clear how well regarded he was, almost every log entry included a personal letter or card wishing John the best, and thanking him for
73 Bruce W1UJR
This was written by Tim, W1GIG. (Thanks Tim!):
John passed away on March 18, 2008. It was 11 years ago that Bruce Kelly asked John to take over the Amateur Radio column in the OTB as Bruce himself was winding down. John was a man of many talents and had a most interesting life. Because he was always so busy helping others, he rarely took time to talk about himself, so I am going to take this opportunity to tell you a bit more about him.
John was born in Guatemala of American parents where his father worked for United Fruit Company (think bananas). At an early age, his father died of malaria and his mother moved the family back to New England. He also lived with an Aunt and later with his much older brother, an airline pilot, who lived on Long Island. As a teenager John discovered radio and his brother bought him a $5.00 two tube regenerative radio kit to build. John built the kit, but it was another 6 months before he got another kit for the power supply. With the help of a ham who lived nearby, he got the radio working which opened up a whole new world for him. John was in High School when his brother went with him into NYC to test for a ham license at the FCC Field Office. For the next couple of years he was active on 40 M. CW using the regen receiver and a Hartley oscillator.
At this point, WW II got in the way. John enlisted in the Army and was trained in radio repair, shipped off to New Guinea, and assigned to be a telephone lineman. The Army moved John steadily North to the Philippines and then to Japan where he was finally sent back to the States for discharge. John enrolled at the University of New Hampshire where he discovered his love of geology. He liked it so much he went on to get a Masters at the University of Nebraska and several years later, a Doctorate also from the University of Nebraska. He continued to work for Chevron exploring for oil in Africa, Madagascar, Spain, Denmark and many other countries including the US.
While he was in college, John remembered his love of radio, but unfortunately his ham license had expired, so he went back in 1954 to test again receiving the call W1FPZ which he held ever since. Later, he tested for his ham license in Madagascar (in French) and in Uruguay (in Spanish). Not many of us have tested for our licenses in three languages! While he was in Madagascar he built many of the transmitters that are still in use at his home. He even wound his own power and filament transformers to get the voltages he wanted.
John also discovered that he was an excellent pistol marksman, but that his results could be substantially improved by reworking the guns themselves, so he taught himself to be a gunsmith. His skills at woodworking, carving, machining, precision casting of bullets and loading target shells were such that this became a major hobby business for him which he pursued right up to recent months.
John was a survivor. While in the Army he survived a major brush with a 3,300 volt power line and later a plane crash while in Africa. Since small planes were the only way for John to get to his job sites, he decided that he’d rather trust his own skills as a pilot than relyon the brush pilots that the oil company had hired. Back in the States, recuperating from his injuries, he got a private pilot’s license, then went on to a multi-engine commercial license with full instrument ratings. Just before he retired, he was working out of Denver and flying his own twin engine Queen Air to Maine to work on his retirement home. He even flew from Maine to the AWA conference one year picking up MarshallEtter, W2ER from Long Island on the way.
Preparing for retirement, John and his wife Liz doubled the size of their new home in Maine. As part of the project, John wanted reliable ham communications with his friends around the world. Limited by normal power regulations, he decided to build a BIG antenna. His final choice was a horizontal V beam aimed at the Southeast. The beam legs were 1,100 feet long and supported on three 100 foot towers. Looking for wire strong enough to span the distance he ran across an ad for #6 phosphor bronze wire run by Marshall, W2ER who had salvaged the wire when he was closing the RCA site at Rocky Point. The two men became fast friends and co-conspirators. Marshall provided quality parts left over from RCA and John, using his metal and woodworking skills, customized the parts to suit his projects. The result was a long series of radio projects that he gave to friends with the caveat that they were required to use them on the air in AWA events.
John always had a fascination with the products of Jerry Gross of NYC. He built a Gross replica transmitter for Marshall who used it for many years. Parker Heinemann, W1YG found an original Gross and had John restore it along with the receiver, station monitor and antenna tuner. They set up an entry in the 1991 AWA contest that exactly duplicated a Gross add from the 30’s and took first place. After the conference, John got a call from Bill Orr who offered John his Gross if John would restore it. That transmitter is part of John’s home station.
Not satisfied with the Hartley oscillator, John discovered that if he used the Colpitts circuit with a split stator condenser and grounded rotor, he could eliminate the hand capacity effect. One of his last projects was to set up the tuned circuit for me and share several of his other construction secrets. The circuit is rock stable on 40 meters.
Thanks for the opportunity to fill you in on some of the less well known aspects of John’s life. It was an honor to know him and he will be missed by all.
Two Stage Telegraph and Telephone Transmitter built by AB9ZG.
One of my antique radio friends built this transmitter some years back, a very true and authentic reproduction. I admired it at the time, not sure I ever worked him with it, but remembered it fondly.
Jon, the builder, kindly entrusted it to me as the caretaker, and looks like, given the weekend weather, I’ve finally got time to get it unpacked, tested, fired up, and on the air. Long, cold winter nights in Maine are ideal for radio.
I was therefore delighted to be contacted a few weeks by Jon, asking if I had interest in his creation. In any case, wanted to share Jon’s handiwork with my radio, and non-radio friends.
It is crystal controlled, you can see the xtal on the right of the upper deck.
The upper desk is the RF section, and the lower deck the power supply and modulator.
Ideally I’d like to find or build an old table so I can set up a replica 1920/30s station, complete with one of the early National SW-3 receivers.
I’ll post more as I get it on the air and operating!
– Bruce W1UJR
Ham Radio QSL Cards – In the early days of ham radio, when making shortwave contact with a station across the state was a novelty, across the country was astounding, and transoceanic contacts where nearly unheard of, hams would confirm contact by sending each other QSL, or confirmation of contact, cards. This tradition continues today, but I today’s mass produced cards are often far less interesting than their early counterparts.
Early QSL cards were often handmade, and frequently included a cartoon, photo or information about the ham’s station, or humorous line art sketch. As both a fellow ham, my FCC issued callsign is W1UJR, and a student of history, I find the early cards very interesting, and have posted a short collection of some of my more intriguing cards
I was fascinated with the “Chair Warmers Club” card, a group of early handicapped hams who met regularly on the air. Back in the day, before telephones and the internet, ham radio was the only real contact these folks had with the “outside world”. W1CJD is “Gil” Gildersleeve, and as you might surmise from his card, the famous artist of hundreds of cartoons in radio magazines of the era.
I found the W8CFD card particularly intriguing, for it appears to the photo show a young ham, along with the caption of “”Believe It or Not” — That’s me over there….”. I looked up Wilven Hagerty of Honesdale, PA, not much found using Google, seems the 81 passing years have largely erased the traces of this fellow.
The W8ECA and W3HVD cards are quite interesting, I have soft spot for cards which appear to be homemade. The W8ECA card in particular looks like someone colored it in with crayons! The other cards for areas near where I grew up – Walton and Norwich, NY or cities where I once lived, Buffalo, NY.
The first thing I like to undertake when staring a restoration is to decide if I am restoring or repairing. For me a restoration is to make the unit look, and function as new again, with correct period parts and repair techniques.
A “repair” means that I am going in to do targeted repairs to make the unit work and play correctly, but not necessarily make it look like new again. This involves cleaning cosmetically of dirt, dust, debris, and whatever else as found it’s way into the set over the last 50 years. For me, this set was worthy of a restoration, at least as much possible, some components, like the old chassis mounted electrolytic capacitors are hard to come by now, and any NOS units are likely to be nonfunctional.
The next step is to document known problems with the set. Fortunately this one played, so that made things easy. Right away I noted the s meter was not operating properly, a common issue with the early National sets, noted some loud 60 cycle hum when the audio was turned down, likely a failed filter cap, and the sensitivity seems low, likely a leaking wax paper cap, and this set has a number of them. So here is where I might differ from the purist. I’ll replace the wax paper caps, and install “orange drops”, without a moments hesitation. While I admire those who will heat the old wax paper caps and hide modern caps inside, I really don’t like to take the time for this, I understand their point, but for me, I’d rather make the set look and play as well as possible.
Someone had removed, and incorrectly installed the HRO dial, a common finding, and the controls needed a general cleaning and lubrication, not unexpected after 80 years.
So my restoration plan for this set went something like this:
- Remove from cabinet, photo document any wire and components
- Check tube voltages to chart, check caps for leakage, plan on replacing all
- Thoroughly clean of the accumulated dust and grime
- Remove and test all the tubes
- Clean and lubricate the HRO dial and gearbox
- Reset the HRO dial properly
- Replace all caps needed
- Recheck voltages
- Check/adjust set alignment
- Play outside the cabinet for a few days to test, then reinstall
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