Trimmer capacitors yaesu ft 101e

Discussion in 'Radio Circuits, Repair & Performance' started by KM4YTW, Jun 30, 2019.

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  1. KM4YTW

    KM4YTW Ham Member QRZ Page

    Hello, another problem i have caused i believe with my 101e is i had a bad 20 meter crystal trimmer on the trimmer deck . The plastic in the trimmer cap i guess was brittle and started coming apart. So i changed it , during removing it from a parts board and installing in my board i think it may have gotten too hot as i heard a funny noise as i was desoldering it . Now i have no output on 20 meters and just yesterday 40 and 80 meters stopped working . The rest of the bands work fine. Any idea whats going on here?
    Thank you.
     
  2. G3YRO

    G3YRO Ham Member QRZ Page

    So you're talking about the trimmers that resonate the Heterodyne Oscillator circuit on each band?

    Only the 160m trimmer has plastic in it (as this is a compression type trimmer) - the others are ceramic trimmers.

    Firstly - does the Receiver still work OK on the affected bands?

    Secondly - check you haven't snapped off any of the wires going to the bandswitch (easily done when hinging out the board to re-solder any trimmers or fixed padders.)

    Roger G3YRO
     
  3. KM4YTW

    KM4YTW Ham Member QRZ Page

    HI Rodger, yes that's the ones. Well the one for 20 meters had a thin layer of something working it's way out of it where I adjusted it, I guess it was a layer of thin gray plastic. Receive works very good on all bands . But 20 meters does have a very narrow area on the pre select. I was thinking along those lines also about pulling the wires off the band switch. I'll check that later today. It's a lot of wires in a tight area.
     
  4. KM4YTW

    KM4YTW Ham Member QRZ Page

    Ok i checked for broken wires , none. With calibrator 100khz i can only get a s9 on 80 meters with the preselector set to 10 meters . I have to set 20 and 40 meters preselector to 160 meter position to get an audiable with the calibrator on 20 meters but i get 10 over s9 on 40 in this position. Sounds like its way out of alignment. But i still dont get any output on 20 or 80 meters. Where would you start with alignment with something this far out.
    Thanks
     
  5. G3YRO

    G3YRO Ham Member QRZ Page

    The first question is - has this suddenly gone wrong?

    Or have you just obtained this rig in this condition?

    My suggested re-alignment procedure for the FT101 is much simpler than that suggested in the Yaesu Manual . . . however, it's for a rig that hasn't been messed with.

    It sounds like yours HAS been messed about with . . . so you are probably best following the procedure in the Manual (which basically explains how to align the RF circuits as if the rig has just been assembled).

    But the good news is that all you need to align these rigs (on Receive and Transmit) is a Dummy Load . . .you just use the Calibrator as a signal source.

    Roger G3YRO
     
    Last edited: Jul 3, 2019
  6. KM4YTW

    KM4YTW Ham Member QRZ Page

    Rodger that Rodger, ill do that and see what i come up with. Is there a test point i can trace the signal for 80 meters? Besides pin 2 of the 12by7. It has been messed with mostly by me! Lol.
    Thanks for your expertise
     
  7. G3YRO

    G3YRO Ham Member QRZ Page

    You really shouldn't need to use ANY test points . . .

    Just follow the alignment procedure and see what happens

    Just peak everything on Receive first before worrying about Tx.

    Using the Calibrator and the S Meter, start with peaking the Het Osc for each band . . . then the RF stage and mixer trimmers.

    (I would at least presume nobody has messed with any of the two IF circuits . . . so leave those alone)

    Roger G3YRO
     
  8. KM4YTW

    KM4YTW Ham Member QRZ Page

    Ok, i followed the service manual and aligned it following your directions. As before 10-15 meters tunes up dandy. I get nothing on 80, 20 and not much on 40. Also on receive for 80 meters i have to crank the preselector to the 10 meter setting to get the strongest signal .
    On 40 receive i have to turn the preselector to 160 meter to get the strongest signal. 20 meters i just get nothing. Also on these bands the 100khz calibrator does not work. The 25khz does work. 100khz calibrator works fine on 10-15 meters. I dont understand why i cant get the preselector back to where it needs to be on receive. .
     
  9. G3YRO

    G3YRO Ham Member QRZ Page

    You didn't answer my question . . .

    Have these faults suddenly started happening? Or have you just acquired this rig?

    What you are saying about the Calibrator doesn't make sense . . . if the 100kHz signal is there on SOME bands, it MUST be there on ALL the bands that are working! Ie it won't just work in the 25kHz position. (unless that band isn't working at all)

    If a band isn't working at all, I suspect the Band Crystal isn't oscillating. Each one will only start oscillating when its Tuned Circuit (resonated with that band's oscillator trimmer) is near resonance - this may be your problem on the various bands that aren't working.

    Bear in mind that if the Band Crystal ISN'T working you MAY hear some signals/band noise if you turn the Preselector to completely the wrong place - this is because you will be resonating the RF circuits to the 1st IF frequency (around 5 MHz)

    So the first thing to check is whether each of your Band Crystals (Het Osc) are working properly.

    Roger G3YRO
     
  10. KM4YTW

    KM4YTW Ham Member QRZ Page

    The problems started after i replaced the 20 meter crystal trimmer on the pb 1188. I agree it doesnt make sense for me to pick up the 25khz and not the 100khz calibrator signal. Checking the het osc crystals is looking for the .3 volt dc on each band from tp1 on the RF board? Or is there another way? I can say i was able to align all the crystal trimmers except the 20 meter. Then i replaced the 20 meter trimmer and here came all the problems. I tried to align them again after the issues and now all i can get from tp1 on the rf board is 2mv . Most of the bands all i can get is 1.7mv . Maybe i can post a video .
     

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