Reconversion from 11M Local Oscillator alignment
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I have a FT-101ZD late Mk2 that had been converted to 11M years ago.? I recently got around to locating the correct crystals and have aligned the TX mixer, driver and RX front end stages per the service manual.? I get good output on all bands and good sensitivity as well.?? However, when transmitting on 15, 12 and 10 meters with more than a few watts of output, the VFO shows an incorrect frequency - several MHz low, not always the same.? Checking the output on another radio shows the transmitted signal is where it should be, so it's the VFO that is displaying the wrong frequency.?? I suspect I need to align the premix local board where the proper crystals have been installed, but the service manual is a bit brief in it's description of the process.?? Does anyone have a "cheat sheet" for this, or perhaps someone has done a video?? I have an oscilloscope, and could whip up a simple RF probe if needed.?? |
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I’m pretty sure if it is showing MHz ?off, but is actually transmitting and receiving at the right frequency … it has nothing to do with the new 10m crystals.? The older display units had toggle switches on them that mix signals to give you the right offset displays.? Maybe better check that out in case it is adjustable.? |
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Would that be the case for a 101ZD MkII?? I've never seen any toggle switches on the VFO although they could be inside the housing. ---------- Forwarded message --------- From: Bruce Collins via <kb0tj1=[email protected]> Date: Wed, Jun 19, 2024 at 12:40?PM Subject: Re: [Yaesu-FT-101] Reconversion from 11M Local Oscillator alignment To: <[email protected]> I’m pretty sure if it is showing MHz ?off, but is actually transmitting and receiving at the right frequency … it has nothing to do with the new 10m crystals.? The older display units had toggle switches on them that mix signals to give you the right offset displays.? Maybe better check that out in case it is adjustable.? |
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Thanks for that - is it any clue that this only happens when transmitting and the power is increased?? I was suspecting a supply voltage issue perhaps with the additional drain on TX. On Wed, Jun 19, 2024 at 12:49?PM Bruce Collins via <kb0tj1=[email protected]> wrote:
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Unplug the two wire harnesses from the display unit and clean the male pins. Plug them back in a few times to make sure all of them or connecting well. Retest.? If no good: As lame?as it sounds, I’d buy a new display unit on eBay, swap it out with the one in the radio now and if still no difference, put it back on eBay! You won’t get stuck with it, they sell fairly easily.? On Thu, Jun 20, 2024 at 5:40?AM Chuck, WS1L via <chandlerusm=[email protected]> wrote:
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Only the older ZD models have the display unit with the toggle switches. I can’t remember when the switched over to the later model.? On Thu, Jun 20, 2024 at 5:40?AM Chuck, WS1L via <chandlerusm=[email protected]> wrote:
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Chuck, WS1L
Bruce Collins