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Heathkit Apache TX1 Saga

Discussion in '"Boat Anchor" & Classic Equipment' started by ZL3OF, Feb 22, 2017.

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  1. ZL3OF

    ZL3OF Ham Member QRZ Page

    Well there were a couple more issues to solve, a lot of hum on a.m. mode, and could only achieve around 60% modulation. Tracked down the hum to the 12AX7 speech amplifier stage and all attempts to solve it failed, so I cheated and reconfigured the 12AX7 heater for 12 volts and supplied it with 12 volts d.c. from a small switched mode power supply which now also supplies the LED panel lights. Voila, no more hum.

    Taking a punt on the 60% maximum modulation problem possibly being caused by soft EL 34 modulator valves, but having no convenient way to check them, I purchased the cheapest EL 34s that I could find. Chinese manufactured EL 34s from Ali-Express for about NZ$15 delivered did the trick, I now have as much modulation as I want. I wonder how long they will last. For comparison name brand EL 34s cost about NZ$60 each.

    Well I promised a picture of the Apache in it's final position in the "Vintage Section" of the shack, and here it is along with it's proud owner.


    The wooden broadcast radio is a family heirloom that I restored. It was purchased by my parents in 1948 as a gift to my grandparents on the occasion of their 50th wedding anniversary.
    I was lucky to acquire the Heathkit SB 610 station monitor recently as they are not common in ZL. It has proved to be very useful with the Apache.
    The ATU was home brewed from ARC 5 components sometime around 1980. I might change the knobs to something older looking.
    The modern Daiwa cross needle meter looks out of place, I shall look for a "period" swr meter.
    The diecast enclosure under the desk houses the 230/110 volt transformer and circuit breaker supplying the Apache.
    The Telex microphone (Turner in the U.S.A. I believe) is actually an electet with a home brew pre-amp in the base.
    The morse key is just for show. The only time I have used it was to get my h.f. licence but you never know, I might use it again one day.
    The headphones are good old fashioned balanced armature inserts. Anyone remember them? Very sensitive in their day I understand.
    The book is an Eddystone publication "Better Radio Reception Information on securing the Best Results From Your Receiver" Price One Shilling.
    And then there is the Eddystone S888A ham band only receiver with outboard S meter and speaker which is the next restoration project. Currently it is as deaf as a post, the only thing it receives is the nearby TS590 @ 100 watts but oddly enough, it is precisely on frequency.

  2. N3DT

    N3DT Ham Member QRZ Page

    I have an AM-2 and an HM-11 SWR meters which are basically the same thing. I'll send you one if you want it. The HM-11 is the better looking of the 2. I can send you pics if you like.
  3. ZL3OF

    ZL3OF Ham Member QRZ Page

    Thank you so much for your kind offer but I think you will find that the cost to ship to New Zealand will be prohibitive unfortunately. I should be able to find something appropriate in New Zealand.

  4. K4RT

    K4RT Ham Member QRZ Page


    Great job working through your TX-1 issues. Nice looking station. I also have an SB-61o I use with my TX-1.

    Brad K4RT
  5. W9GB

    W9GB Ham Member QRZ Page

    Telex purchased the Turner company (1930-1979) in 1979. Cedar Rapids, IA headquarters and factory was closed shortly after.

    Your microphone is the Turner 250 series (25x models).
    Here are High Quality PDF of Turner Microphone Catalogs

    1962? Turner Microphone catalog (12 pages)
    250 series on first pages

    1972 Turner Microphone catalog (24 pages)
    250 series on page 13
    Last edited: Jan 13, 2018
  6. W9GB

    W9GB Ham Member QRZ Page

    1956? Turner Microphone Catalog (PDF) — 16 pages, Attached

    Attached Files:

  7. KL7KN

    KL7KN Ham Member QRZ Page

    Thank you for taking the time to document both your troubleshooting steps/results and the fix to cure. Also, love the photos of the vintage Eddystone, I look forward to you sharing that journey.

    Best of luck with your new-old station
  8. W9GB

    W9GB Ham Member QRZ Page

    Turner served as the OEM supplier for other electronics manufacturers (primarily radio and PA system mfg.). McMartin, based in Omaha, Nebraska (USA), sourced the Turner’s 250 desk microphone for their PA product lines.
    Here is the McMartin 250 specification sheet (2 pages, PDF)
  9. ZL3OF

    ZL3OF Ham Member QRZ Page

    Thanks for the info, always interesting to have some background on older equipment.

    Don, I suspect that the Eddystone will prove to be quite a journey. The Apache took me over a year. I learnt, or re-learnt a lot and quite enjoyed the ride. As a bonus it was completed on my 64th birthday which was a nice present to myself.
    A Heathkit restoration is a good place to start because of the readily available documentation and the online help available from others. It has provided good training for tackling the Eddystone which is not a suitable project for beginners.

    My h.f. antenna is an 80 metre doublet fed with 300 ohm t.v. ribbon to an SG 239 auto tuner where it enters the shack and then coax to the TS590. The SG 239 is not rated for 100W a.m. so probably would not survive the Apache at full power. Just for grins and a bit of whimsy I have decided to switch the 300 ohm line with a home brew knife switch made out of ....... errr......... knives.


    I could have switched at 50 ohms but that would be boring. The idea is to go "old school" so no change-over relays or ptt arrangement either. The ideal would be separate transmit and receive antenna but that might not be practical at my QTH.

    Last edited: Jan 14, 2018
    KP4SX and AD5HR like this.

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