So I Bought A Swan 350

Discussion in '"Boat Anchor" & Classic Equipment' started by AF6LJ, Jul 11, 2014.

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  1. AF6LJ

    AF6LJ Ham Member QRZ Page

    A few weeks back an offer was extended to me by a Zedder who had heard my interest in acquiring a Swan 350, an original not the one that came toward the end of the company's life. Sometime later I picked up a Swan 117XC power supply, while not the power supply that originally sold with the radio, it is for the most part the same supply with a few minor changes in its appearance.

    Okay so why a Swan and why one now?
    The simple answer is just because....
    Actually I am looking for an easy "daily driver" to get on the air for my 75 and 40 meter activities while I preform some overdue maintenance on my other gear. In addition I like the sound of those old Swans, they have good audio on TX, RX audio is nice but not great, good enough for comfortable listening anyway....

    The radio was powered up after verifying the power supply wouldn't self-destruct when mains power was applied.
    At first nothing.....
    Then the AC cord was removed and the pins on the back of the power supply were twisted slightly in order to assure good positive contact. Upon re installation of the cord power was applied and the lights and filaments came on. Audio..... Nope.......

    A little tapping reveled intermittent relay contacts. Well I happened to have a new never used 4 pole, double poll relay with the proper coil voltage and resistance and just dropped it in, that fixed all the intermittent issues.
    In spite of higher than normal ripple in the power supply some tests were conducted...

    The receiver appeared to be a little numb although it could hear a half microvolt. There is an AGC issue and no S meter indication until a lot of RF is applied to the antenna connector, a lot in like .5mw....
    Reception on the air on twenty and forty meters was fair to good in spite of the AGC issue...
    The radio was very solid after a half hour warm up.

    On the transmitter side...
    The radio loaded up and put out 200W with little effort in the CW mode on 40 meters. The carrier could be nulled and the transmitter audio was not distorted in spite of higher than normal hum levels on the audio. The cathode current meter works just fine, it will be checked to make sure it is somewhat accurate.

    I had another project I needed to order parts for, I also like to buy a few extra in order to expand my available stock of new parts so a decent sized order was placed to Mouser, that order came in last Wednesday.

    A very decent quality printed copy of the manual was generated along with the pages from the Swan 500C manual regarding the 117XC power supply....

    Sorry for the less than sharp picture, they will get better, I took this one in a hurry this morning.

    Stay Tuned.................
  2. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Lookin' good!
  3. WA6MHZ

    WA6MHZ Ham Member QRZ Page

    I hava coupla Three drifties, and a coupla 500CXs, and a 700CX and more Swans as well. The only one I am short are the 600T & 600R
  4. AF6LJ

    AF6LJ Ham Member QRZ Page

    With any repair / reiteration project the electronic portion always begins with the power supply, it is not possible to effectively troubleshoot a piece of gear without establishing that the power supplies are healthy.
    So this is where we begin.....
    This power supply has that old gear smell, old caps, old resistors and the smell of well aged transformer pitch...
    The compact design of this supply requires dissassembly in order to replace the caps, besides this will enable a little clean up and wire replacement where necessary.
    A little dried rat snot indicating it is well past time for an overhaul.

    Plenty of photos have been taken in order to ease reassembly...........
    Stay tuned......
  5. N2EY

    N2EY Ham Member QRZ Page

    I don't see any pictures yet but that may be settings on my end.

    All the electrolytics are almost certainly "tired", of course, even if they aren't completely bad. Same for PS diodes, plus all the usual suspects - carbon comps, wax paper caps, tubes, etc. (You know all this, of course, but some readers may wonder exactly what gets changed out).

    The good news is that there obviously isn't anything REALLY BIG wrong. Just a lot of little bits here and there. Will probably be a good rig when all is said and done.

    What will be REALLY interesting is seeing how bad the drift really is, particularly once things are shipshape.


    There IS a way to fix the drift on Swans, Eico 753s, NCX-3s and similar early rigs. But it's a bit drastic.....

    What is done is to tear out the original VFO and install a DDS VFO kit such as N3ZN sells. Digital readout, stable as a rock, plus features such as memories and RIT. Of course the kit represents a considerable amount of money, and unless you put it in an external box the rig will have to be torn up a bit to install it - not the path for a nice old rig. But if one happens upon, say, a 753 with a messed-up VFO, it could be a path to investigate.

    Good luck!
  6. W9GB

    W9GB Ham Member QRZ Page

    Morris Dillingham, KI4IUA installed the Cambria X-Lock into the Swan model 270B (Cygnet).

    Cambria X-Lock 3 VFO Stabilizer

    Cambria X-Lock Solutions
    Specific details on installation in older radios

    Kevin Rea, K6REA did offer a replacement single-sided HV board for the Swan 117X HV supply.

    Stephen, KB7BGS also offers a replacement double-sided HV board for Swan 117X/117XC power supply, kit for $75.

    Swan Power Supply 117X
    Introduced in 1965, the Swan 117X universal power supply remained in production for more than a dozen years. Without any change in design it was produced longer and in greater numbers than any other Swan product. The "universal" meant it was capable of both AC and DC operation. In order to accomplish each mode using a single power supply, a rather interesting power transformer was required.
    In this case, the 117 VAC primary and high, medium and bias voltage secondary are of standard construction. The low voltage winding, however, is actually an 18 VAC secondary with 9 VAC and 12 VAC taps. With AC operation, the 12 VAC tap is selected through connections at the 15 pin Jones connector and feeds filament, lamp and relay current to the appropriate output terminals.

    Attached Files:

    Last edited: Jul 11, 2014
  7. N2EY

    N2EY Ham Member QRZ Page

  8. W9GB

    W9GB Ham Member QRZ Page

    Jim -

    Go to Dale, W4OP web page of classic radio restorations.
    Dale used the X-Lock for his 2012 restoration of the Hallicrafters FPM-300 MK II transceiver (photo attached).

    You will see that Dale has used the Cambria X-Lock 4 on many of these vintage radio restorations.

    The Cambria X-Lock is the latest derivation from the original Huff-N-Puff designs by Klaas Spaargaren, PA0KSB (SK).
    Klaas first wrote about his design in the RSGB RadCom magazine in July 1973.
    Jim Fisk, W1HR/W1DTY (SK, 1980), then editor of Ham Radio magazine, featured this approach later in 1970s

    The Huff-Puff technique is a method of stabilising the frequency of ordinary L-C VFO's.
    Most VFO constructors will have experienced great difficulty obtaining a stable frequency,
    at least without careful attention to temperature compensated capacitors etc.

    The Huff-Puff approach, pioneered by the late Klaas Spaargaren PA0KSB in 1973,
    resulted in a rock-stable VFO effectively locked to a crystal-derived reference frequency.
    Over the years several magazine articles (RadCom, Ham Radio, QEX) have appeared describing
    both the original circuit and subsequent enhancements.

    Attached Files:

    Last edited: Jul 11, 2014
  9. AF6LJ

    AF6LJ Ham Member QRZ Page

    The pictures are there Jim, they may take a while to load depending on your Internet connection.
    The carbon comps, electrolytic caps, and diodes will all be replaced.
    For those following along who are as technically savvy as some of us; the reason for replacing the above mentioned parts is because they deteriorate with age. The Electrolydic capacitors dry out and are no longer effective at filtering the ripple out of the DC. The diodes are of an older technology and were not intended to last this long, even though the majority of them do, they get leaky over time and will eventually short out. The carbon composition resistors change value with age, they are simply clay mixed with carbon pressed into a form with wires on each end and there are much better technologies now.

    As for the drift, I don't expect it to be very bad on seventy five and forty meters, however the best way in my opinion to deal with the drift would be to use an external DDS VFO and leave the radio as is. An eight pin keyed plug and socket can be obtained added to the radio just like in the later model Swans, there is a punch out with a cover in the back where the External VFO connector is supposed to be. So that is really no big deal...

    The +12V relay supply has been rebuilt, and the+300V supply has new diodes. All the bleeders have been replaced, and I shall confess my sin up front. The original bleeders were 150K 2W comps, I replaced them with 100K 3W resistors, they will do fine.
    Forgive me Father for I have sinned, I have failed to comply with your holy configuration controls, please have mercy on my soul and abilities as a technician. :D

    Well time for lunch and to rest my already strained eyes. :)

    More to follow after lunch....
  10. N2EY

    N2EY Ham Member QRZ Page

    I was familiar with the HuffPuff stabilizer, but the X-Lock kit is a new one on me. It appears to be relatively simple, inexpensive and easy to apply - or remove.

    Thanks again!
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