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Different versions of Dentron Clipperton-L........help!

Discussion in 'Amateur Radio Amplifiers' started by G4JBH, Feb 11, 2019.

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  1. G4JBH

    G4JBH Ham Member QRZ Page

    I need some advice please guys!

    I was in the process of restoring an early Clipperton-L with a serial number of 0745. So far, so good.

    Just bought a second one as a source of spares with a serial number of 3734. The owner had changed the meter, disabled the meter switch so it just reads anode current and messed around with it a bit, hence my logic in using this one for spares.

    Removed the lid and it has some major differences to my early one:

    1. A whole PCB attached to the valve bases rather than the tag strips.

    2. Different coils and doorknob capacitors in the PA compartment.

    3. Longer choke feeding the anodes with much shorter chokes running to the anode caps.

    4. The transformer is physically slightly smaller.

    Now I don't know what to do - could the anode connections be directly swapped over for starters?

    Is anyone familiar with the differences? Now I need to work out if the circuit diagram I have in the .pdf manual is for an early or late amplifier.
     

    Attached Files:

  2. G4JBH

    G4JBH Ham Member QRZ Page

    The plot thickens!

    Just made another search on the Internet and it looks like the PCB is the one used in the final Clipperton QRO.

    There are some other similarities like the larger silver capacitors on the HT board and a multi-core cable running from the PCB to the band switch.

    I've attached another photo - the PCB has been bodged-up a bit with an extra relay added by the look of it.

    Have I somehow bought a Clipperton QRO in a Clipperton-L case! Either way, it doesn't have the tuned input board, but not bothered as good old eBay found me a CM-1.
     

    Attached Files:

  3. KE0ZU

    KE0ZU Ham Member QRZ Page

    Just got the new issue of Electric Radio magazine today and there is a rather lengthy article by George Misic, KE8RN, about "Dentron" with some interesting information you might well find interesting. The fellow writing the article was the Chief engineer at Dentron for a couple years.

    You might contact him at KE9RN@comcast.net.
     
  4. N8CMQ

    N8CMQ XML Subscriber QRZ Page

    I like the early unit over the later one, as the PC board and other improvements were not really improvements in my book.

    The RF choke that the parasitic suppressors are on are not a problem other than there should be gaps breaking up the resonant frequency on the choke.
    The suppressors have a resistor in the RFC, and they should be outside the coil on the newer unit, the resistors should be added to the older unit.

    The caps and other parts change due to supply or cost, but should be interchangeable if the values are the same or close.

    These amps, if found cheap, are fun projects that add a good kick to the ego as well as the signal.
     
  5. KE0ZU

    KE0ZU Ham Member QRZ Page

    I bought mine for cheap several years ago because it didn't work. I found the CM-1 board had been field installed and done erroneously, and it had a new set of 572Bs. Who could ask for more? Fixed the field mod install, and its been a very good amplifier ever since.
     

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