ad: portazero-1

DX-60 Initial Test Problem - Tune Level and Final Tuning Problems

Discussion in '"Boat Anchor" & Classic Equipment' started by W1FMX, Jul 30, 2021.

ad: L-HROutlet
ad: l-rl
ad: L-MFJ
ad: abrind-2
ad: Left-2
ad: L-Geochron
ad: Left-3
  1. W1FMX

    W1FMX Ham Member QRZ Page

    Hi, Pheel.

    About L1, I was responding to your earlier comment, "I think what you heard sizzling was the L1 coil." So, that is why I spoke about trying to find another L1 just in case it has also may have a problem. But, I get resistance when I check L1 with a DMM and moving the core does get results, so I expect it may be o.k.

    Sorry that I was not clearer , but L1 is not open.

    It is the RF Choke that appears to be open.

    Thanks for the info on RF Choke - will look at Mouser again and order a replacement for the RFC.


  2. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    Ok, time out.

    I was thinking more about L1, the Driver Plate coil (part #40-337)...will try to get one, too.

    L1 is NOT the Drive Plate coil, so I am at a loss as to where you came up with this conclusion. The Driver Plate Coil is obviously L2.

    The Hammond choke I recommended was as a replacement for L1. L1 is a choke, a variable choke which is almost unobtanium, its value is approx. 100uH. So we have to replace it with a "Fixed" inductor choke. Simply because L1 shows resistance does not mean it is ok. When you get your LC meter take it out of circuit and measure it.

    Now you mentioned another choke - which one is it? Again be specific.

    There are three other chokes in this transmitter:
    1) the V2 grid choke which is 1 mH
    2) the V3 grid choke which is 1 mH
    3) the V3 plate choke which is 0.425 mH or 425 uH.

    From recent resistance tests, the V1 plate choke L1 and the V2 grid choke appeared to be functional.

    Last edited: Sep 13, 2021
  3. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

  4. KM4OZ

    KM4OZ XML Subscriber QRZ Page

    This makes for interesting reading and will likely come in useful when I restore my original sloppy 13 yr-old built (me) DX-60 B in my upcoming, but not-soon-enough-retirement. My problem like many others is not having crystals and reading many different things on availability and function. I would love to have a decent functional XTAL for one freq each for on 80 40 and 15 and open to sources, and also preferred frequencies where the cw slower speed boat-anchor crowd congregates. Somebody who could produce and sell such an affordable "3 pack" for the DX60 and related nostalgia crowd might stand to make dozens of dollars!
  5. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    I had published a 5-part series on a Screen Modulated 3-Band build from scratch on QRZ. I thought I had placed it in the QRZ AM Forum but cannot locate it.

    If anyone is interested in drilling, punching and soldering a build from scratch, I can send them the files, which includes chassis data, theory, parts lists, and schematics.

    As for crystals, WD8DAS has resumed operation of the AF4K crystals business.

    Last edited: Sep 15, 2021
  6. KM4OZ

    KM4OZ XML Subscriber QRZ Page

    Great, thanks, and thanks.
  7. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    OK, found the thread.

    It was originally started as a Holding thread to preserve circuit schematics relating to the AM mode but got hijacked by other postings; imagine that. :rolleyes:

    I still have a hard time wondering why people can't upload a schematic package as simple as LTSpice (takes about 0 minutes to learn) and preserve those old schematics.

  8. W1FMX

    W1FMX Ham Member QRZ Page

    Hi, Pheel and All.
    Wanted to follow-up on the status of this project. The DX-60 is working again - what turned out to be the problem? It was R13. When I restored the rig, I had replaced the "out of spec" R13 (8.2 Ohms) with two resistors in series that equaled 8.2 Ohms. A friend looked at the rig and found the problem that I missed. It turned out that one of those two new resistors used to replace R13 had failed - I never re-checked them as I assumed they were good. Learned a lesson - even though they checked out before I installed them, I won't assume that any part is still good later. Thank you again for your patience and help as I worked on this radio!
    N2EY likes this.

Share This Page