75A-4 mods: 1s that work well

Discussion in '"Boat Anchor" & Classic Equipment' started by W5INC, Jan 25, 2015.

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  1. KA9JLM

    KA9JLM Ham Member QRZ Page

    That is interesting. Nice find.

    My Twins were special order and came from Collins with the 4CX250B tubes.

    I could not imagine building one, But it is all hand made and easy to work on.

    Smells good too.

    Enjoy your project.
  2. W5INC

    W5INC Ham Member QRZ Page

    Could I trouble you Mr. Don, for some pics of your KWS-1 and the PS, so I can have a go by to what the factory assembly procedures looked like, since yours is a known factory produced piece? That would sure make for a very good benchmark, to see if a unit I am thinking about purchasing is factory assembled or a piece that young Tom Edison cobbled together. IMO, the factory assembled piece would have more value to it, then a piece put together outside of the factory by a unknown individual. Hard to beat the QC aspects that happens with inspections at the factory. Along with the practical assembly knowledge of the folks who actually put the units together originally, everyday at work. :)
  3. K9STH

    K9STH Ham Member QRZ Page

    The "kits" were not down to the component level! They were just complete sub assemblies that could be combined to make a total package.

    Collins originally advertised the 32W-1 exciter which could be combined with the amplifier / power supply to make the complete transmitter. However, the 32W-1 was never produced outside of a few prototypes. In fact, the KWS-1 was originally called the 30L-1 and was advertised as such.

    30L-1 1a.JPG 30L-1 2a.JPG 30L-1 3a.JPG 30L-1 4a.JPG

    Between the time that the advertising campaign began, and the actual availability of the equipment for general sale, Art Collins decided to change the name of the transmitter to KWS-1 and not to produce the 32W-1. If one looks close at the early KWS-1 advertisements, it can be seen that the pictured unit still has 30L-1 on the escutcheon! Since the 32W-1 was not manufactured, there were no "kits" actually sold that I know of.

    The "kits" were like the Johnson Invader 200 / Invader 2000. One could purchase the exciter and then, at a later date, add the amplifier.

    Even if a few "kits" were actually sold, it would be virtually impossible to tell the difference between a "kit" and a factory assembled KWS-1 because the basic units were assembled at the Collins factory.

    Glen, K9STH
    Technical Adviser
    Collins Collectors' Association
  4. W5INC

    W5INC Ham Member QRZ Page

    So if the KWS-1s themselves were built at the factory in component/stages that could be added at a later time, how did the PS kit come Mr. Glenn? Did the PS cabinet have the holes drilled for the lights, hinges and handle for the door? Was the transformer already mounted in the cabinet along with the wiring harness being in place already? Or did some boxes come to the QTH, with all of the parts inside to make the PS with the same parts the factory used and you put it together? Back at this snap shot in time, folks were a lot more hands on in construction projects then they are in today's AR market.

    For future reference there Mr. Glenn are you a single malt Scotch person? Just in case you get unlucky enough in the future, to cross my path sometime, to where I could possibly buy you a palliative drink at that time. Thanks once again for sharing your knowledge with the Forum here. :)
  5. K9STH

    K9STH Ham Member QRZ Page

    There were really not any of the "kits" shipped since none of the 32W-1 exciters were sold to the public. There may have been a couple of prototypes made. However, finding one of those assembled kits would be basically impossible. I had not even heard of these kits. I was still in elementary school when they were proposed and definitely did not have an amateur radio operator's license.

    Art Collins was famous for dropping projects in mid-stream, for all sorts of "strange" ideas, for making modifications to designs that really were not needed, etc.

    An example is the KWM-3 transceiver. This was to be basically a 718-T commercial SSB transceiver with the frequency coverage moved down from 2000 kHz to 1800 kHz. The first time I met Art Collins was my 2nd week of working for Collins, here at the "new" corporate headquarters in Richardson, Texas, straight out of college. Eric Tedley's industrial design group was part of Process Division in which I was employed. That group had been charged with coming up for cabinet designs which would then be approved by Art. One of the assistant division directors knew that I was an amateur radio operator and invited me to this unveiling.

    Art looked at the various designs and then said he would make a decision later. It was not long before the KWM-3 project was dropped and no new amateur radio equipment was designed until the KWM-380 which was a completely different design.

    Art had a bad habit of making very minor design changes to equipment and insisting that these changes be made before the unit left the plant. Then, before the units all got modified, he would come up with more changes. The result was that no equipment was being shipped and, therefore, there was no income to the company. To combat this, every division had an "Art project" to keep him occupied. Basically, none of this equipment was ever intended to ship. But, by keeping Art Collins occupied, other units could be shipped and the money kept coming into the company.

    In the mid 1960s, there was an article in the Wall Street Journal about the Collins Radio Company. That article basically stated that the company survived "in spite of" and not "because of" Art Collins. Needless to say, the WSJ was not popular, by decree from Art, around the Collins Radio Company.

    There are a number of different happenings, with Art Collins, that I am aware of and those situations would "fill a book"!

    Glen, K9STH
  6. KA9JLM

    KA9JLM Ham Member QRZ Page

    I will see if I can take some pictures.

    It is a work of Art

    Enjoy your project, take some pictures if you can.
  7. W5INC

    W5INC Ham Member QRZ Page

    I sure appreciate the help Mr. Don! I will be getting with my powder coat guy and see if they can match the original color of the A Line pieces. They do have a computer color matching system so they should get it close I am thinking. The front panel's lettering is clean and very crisp so no work needed on that area of the cabinet. The very back of the top lid has some slight rub marks that have wore thru the paint, but if powder coat color isn't dead on, I will simply leave it alone. I have garnered rather large amounts of 6BA6 / 6AL5 Phillips JAN tubes for the project and should have more then enough to last a few lifetimes. I sure don't want to go in the tube biz but if any of the BA folks who have posted answers in this thread need either of these variations of tubes send me a PM and you can have them at my cost. Much better price then the tube vendors out there. I was looking around in the tube bin and ran across some 12AX7s I was going to use for the SB #1 mod. It is a tube made in Russia and can't remember how I acquired these tubes years ago. I am guessing here the tubes made in UA land are good quality pieces, or at least I am hoping so. :)

  8. K9STH

    K9STH Ham Member QRZ Page

    The formula for the St. James gray paint used on the Collins "A-Line" is the first one listed at:


    Of course, there were slight variations in the exact color due to "batch" considerations. However, the paint, using this formula, is "spot on" when compared to a number of cabinets where the original paint from areas of the cabinet that have not been exposed to "the elements" for decades.

    I have paint "matched" from areas of the cabinet that are protected from the sun, etc., like the "lip" where the rack panel is in contact with the cabinet itself. The who idea of restoring the paint is to get the color when the unit was new, not the color after decades of exposure.

    The formulas are from Sherwin-Williams. However, any good paint store can use these formulas because the colorants are "industry standard".

    Glen, K9STH
  9. W5INC

    W5INC Ham Member QRZ Page

    Going to be carving some time out on Sunday mornings to get this 75A-4 back to being squared away. 1st pic is the back of the top lid and the paint loss that is there. I will simply get some paint and touch that area up as the rest of the cabinet's paint is very good. Will worry about powder coating the cabinet at a later date. The second pic will show the inside chassis of the radio, that is dusty but in very good shape other wise. It will take a little elbow grease to get the unit back to being guised up and in clean shape once again. It will be more then worth while once completed. I diluted some Windex in warm water and used a tooth brush and paper towels to clean up the dust deposits on the chassis. I dilute the Windex so there is no problems with rubbing off any of the ink that is printed on the chassis at the present time.




    I am waiting to take the side panels off before I clean the rest of the chassis. I will do the cap replacements and SB mod work 1st, which is all under the bottom cover of the rig. These radios are built like a tank and have plenty of attachment points for the cabinet covers. A sturdy box to say the least. Looking around the bottom of the 75A-4 I can see that the S meter mod is done, which is a great relief to me. Sure didn't want to have to gather the 2 potentiometers which might not have been to bad, but the standoffs holding the mounting plate up for the potentiometers might have been a different kettle of fish. The hum mod hasn't been done to the radio as of yet, which shields the wires going from the power transformer T6 to the rectifier tube V17. I think I have some old mic wire that is shielded and will pull the mic wires out of that shielding and see if I can use this to preform the mod with. This shield wire from a mic cord might be to large in diameter to work for the mod, but I shall see. I will be checking what other parts are needed to complete the SB mods that then hit Mouser on Monday to order the caps and SB mods up, all at 1 time. I really got that blast of BA scent when removing the bottom cover of this rig and looking forward to hearing some noise coming out of the BA box here in the near future. :)

  10. W5INC

    W5INC Ham Member QRZ Page

    Got some of the tubes I ordered and still waiting on a few more tubes that were bad when tested on the TV-7. The 5Y3GTs, 0A2s and the 12AT7s I am still waiting on & should have more then enough 6BA6s and 6AL5s. All JAN tubes except for the Russian 12AX7 which did test perfect in the TV-7 so it should be fine, I reckon. It seems that GE is back to making some vacuum tubes in of all places of Uruguay for some strange reason. I guess GE moved their tube manufacturing plants to SA for labor and material costs. But at least some new tubes are making their way back to the market place, which is a good thing. :)

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