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Search results

  1. nomadradio

    Gloden falcon? 1×3×6

    I came to think of this amplifier as "a bridge too far". The designer found the upper limits for this kind of design by going beyond them. There was never a schematic diagram published for it. It used a seemingly-wrong combination of tube types. Had one pair of tubes in parallel, but each...
  2. nomadradio

    President washington

    Would be helpful to know what your test setup is. Do you have an external frequency counter that shows the frequency of the AM transmit carrier? When you said "upper and lower" do you mean USB and LSB on the mode selector? If what you mean is that there is no transmit in AM mode, please fill...
  3. nomadradio

    galaxy dx 33 hp2 problems

    Pin 9 is being fed from one of the two 4008 chips. If that voltage is wrong, this is where it comes from. Question is why? I'm used to watching the VCO tuning voltage on the 'scope while changing bands. You might want to see if the voltage at pin 9 changes when the band switch is changed. If...
  4. nomadradio


    The PLL in that radio requires both a new crystal and an oscillator circuit for that crystal. In addition, the kit's oscillator must contain its own clarifier circuit. The factory clarifier will not function properly by itself outside the 40 CB channels. The internal frequency feeds into pin 4...
  5. nomadradio


    And maybe the spectrum coming out of the radio contains some energy that's not exactly on the channel selected? If it does, the SWR will read high, since all the RF energy at frequencies out in left field gets reflected. The radio's internal SWR meter just adds all those frequencies together...
  6. nomadradio


    Good question. You would have to program it to jump frequency 455 kHz when the mike is keyed. That's what the factory PLL chip does. 73
  7. nomadradio

    Troubleshooting Muddy buzzing receive D&A Mavrick

    Hmm. Might start with narrowing down which specific amplifier this is. The MDX was an attempt to get the thing sold under the FCC radar by pretending it was a crystal-controlled ham CW-only transmitter. Not so different from what Texas Star does these days. Didn't work. D&A closed anyway. The...
  8. nomadradio


    I have heard that, too. Bought some to play with a while back. I should see if I can find them and see if they baffle the chinesium tester the same way. 73
  9. nomadradio


    So it's a good thing I decided to just knock off at the end of a long Saturday with the 69 base. A fresh look reveals this black jumper plug. Pull it off, and a spare 2-pin 2.5mm plug is used to put the current meter in line with the two left-hand RF transistors. The plug used for the internal...
  10. nomadradio


    Well, I misspoke about this radio. It was the black radio that was fixed before this one Saturday that needed the modulator transistors. They were okay in this one. Turns out that setting the bias trimmer pots for zero Volts will get you zero Watts. That's where I had preset the trimmer pots...
  11. nomadradio


    Ah, okay. So what's wrong with this picture? This is the tester we use to match Vth every batch of IRF520 and FQP13N10 parts. Yes, it's a new unused RT1 MOSFET. And yeah, both the testers like this one that we use show the same result. My intuitive guess is that the gate-voltage...
  12. nomadradio

    found this on youtube on how to test new final

    Simple way? Yeah. The width of the package. A real Mitsu 1969 is skinnier than the standard TO-220 metal-tab transistor package. Can't remember the exact dimensions. But it's visibly thinner than every TO-220 part. Easy to see in the thumbnail pic above. The skinny gray one on the left is the...
  13. nomadradio


    Before you can check a transformer, whether at normal or reduced voltage you need to unhook the shorted circuit that's overloading the transformer. The filter capacitors are usually only good for 20 or 30 years, tops. An amplifier that had low mileage might get closer to 40 years from those...
  14. nomadradio

    Pdc250 frequency counter on Uniden washington

    There was a different model, the PDC256 that was built with an internal offset feature. It had no antenna-coax sockets since it was built to tap directly into the radio's VCO the way you hooked up this one. There were four so-called "DIP" switches that served to select the frequency offset. This...
  15. nomadradio

    FL-2000B High input SWR on 10 and 20m

    Okay, the killer "B". 73
  16. nomadradio

    Older Connex 3300HP-ZX mod identification?

    Two chains in that radio. Removing TR32 severs both. TR53 only one of them. Still only a lesser evil. This radio has a little more going on in it than a Cobra 29. 73
  17. nomadradio

    FL-2000B High input SWR on 10 and 20m

    Ended up on a tangent about the FL2000 and the sweep tubes it used. Then I figured out you're discussing a FL2100. Oops. 73
  18. nomadradio

    Older Connex 3300HP-ZX mod identification?

    You could pull out TR53 and move it to the empty TR32 spot. TR32 has two limiting functions, TR53 is used for only one of the two. Installing TR32 will allow the mike amp to hold its own output below the distortion level, even though the AM mod limiter will still be missing. A lesser evil if...
  19. nomadradio

    Older Connex 3300HP-ZX mod identification?

    On the inside it's pretty much a Galaxy DX33HML with a different name badge. The ID number on the front edge of the circuit board isn't terribly clear in the pic, but looks like "EPT3600-14C". This was the last revision before the lead-free rules kicked in. It's documented here, along with the...
  20. nomadradio

    Texas Star 250/350 pill mount

    It's an american-size allen wrench, but I can't remember the exact size. The screw thread is #4, 40-pitch thread. Every set of small american-size allen wrenches we have included this one. Whichever it is. 73