G3YRO's FT-101 Series Tips

Discussion in '"Boat Anchor" & Classic Equipment' started by KB3GWQ, Jul 8, 2018.

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  1. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Roger, G3YRO, is the resident FT-101 man and he has some good advice that I have not seen in the service manuals and get's buried in these threads. I think it would be a good idea to have it all in one thread on the first post and just edit it accordingly with any additional tips so this stuff doesn't get lost forever and we can just reference this thread accordingly. Roger if there's any stuff here you want to add/edit/etc. let me know.

    * Adjust SSB Crystals on PB-1184
    1) Go to USB. Turn on 100hz calibrator.
    2) Rotate dial so the tone is about 1000hz.
    3) Adjust preselector for S9+ 10dB.
    4) Rotate tuning dial to lower the tone and STOP at S9.
    5) Adjust USB variable cap to shift the tune to 200hz (it may have been higher
    or lower than this to start with).
    6) Repeat 4 and 5 in the LSB position, and adjust the LSB Trimmer.

    * S-Meter Calibration
    1) Turn the Calibrator to the 100kHz position.
    2) Tune in the signal so the tone is around 1kHz on 14.200.
    3) Peak the Calibrator (making sure you have a Dummy Load connected, or else it
    will read incorrectly).
    4) Set the S Meter pre-set so it reads S9+25dB.

    * Power Output and Alignment (Re-check every ~5 years and when changing tubes)
    To adjust these Trimmers, tune up in the normal way, then reduce the Carrier
    knob so that you only have around 100mA PA current... then peak the
    trimmers for maximum current on the meter (that equals maximum drive).

    So it's best to do one band at a time. The best way to do this is in the
    middle of each band, with a Dummy Load connected, and using the Calibrator
    on receive, and adjusting the power level to 100mA, as above.
    Turn the Carrier control back down if the current gets higher while adjusting.

    1) Peak the calibrator signal on the Preselector (to give you a starting
    2) Transmit, and peak the Band Crystal Osc Trimmer for that band for max
    3) Transmit, and adjust the Preselector Knob for max current.
    4) Transmit, and adjust the Grid Trimmer for that band for max current
    (careful not to short the trimmer to the screening plate,
    as there is high voltage on it!).
    5) Transmit, and peak the Mixer Trimmer for max current
    6) On receive, peak the RF Stage Trimmer for maximum S Meter.
    7) Go to the next band and do it all again.

    Note: On 10m, there is NO Grid Trimmer... so ignore Step 4... Do Step 5...
    but then try re-adjusting the Preselector knob to see if you get more
    Current (Step 3)... if it increased, you will then have to re-peak the
    Mixer Trimmer again, and repeat these two steps until there is no improvement
    in the power level. This 'juggling' will only be necessary if the Valves you
    are using have very different internal capacitance to the original ones.

    * Tuning Up
    1) Once on the part of the band you want to operate on, tune in the Calibrator
    and peak the Pre-selector on Recive for max S Meter.
    2) Set the PA Tune capacitor roughly where that band is marked, set the
    Load capacitor to 0.

    (with a few seconds gap between each transmit burst)
    3) On Tune position, go to transmit (using the PTT so you can do it in short
    bursts) - start with the Carrier level low (Number 3) and peak the
    PA Current for max using the Preselector.
    4) Next, rotate the Tune control for a Dip, ie minimum current.
    This should also correspond with a peak in output on your external
    Power Meter.
    5) Now turn the Carrier level up full and see what the PA Current is reading.
    When the PA is properly Loaded, you should end up with nearly
    400mA dipped current.
    6) Presuming the dipped current is still low, advance the Load control
    one notch, then re-dip the PA current using the Tune control.
    7) Keep repeating the last step, one notch at a time (in short bursts)
    until you no longer get a proper Dip. So then go back one notch on
    the Load control. This should also correspond with maximum RF Output power
    on your external meter.

    * Misc Stuff
    - If calibrator signal is weak Antenna Relay is not at fault as that goes in AFTER the relay.
    - FT-101 series uses Grid Block Keying.
    - To test other rigs for grid block keying or cathode keying:
    use a multimeter across the end of a cable plugged into the Key socket.
    Switch to Transmit and then read the open circuit voltage.
    Then with your meter on a Current range, switch to Transmit and
    measure the current it takes to short out the line.
  2. KE4CQ

    KE4CQ Ham Member QRZ Page

    Great summary! I plan to work on my new FT101E this weekend.

    You mention that the 10m band does not have a grid trimmer. I show that it has a grid trimmer (TC5) but not a plate circuit trimmer. Maybe I am looking at this incorrectly?

  3. G3YRO

    G3YRO Ham Member QRZ Page

    The Trimmers that ONLY affect the transmitter are in the Grid of the PA Valves, or the Anode of the Driver Valve, which ever way you care to look at it ! (so I have called them Grid Trimmers)

    So there is no Grid Trimmer for 10m.

    TC5 is the 10m MIXER Trimmer.(as are the corresponding trimmers for the other bands)

    The Mixer trimmers affect Tx and Rx (but more critical on Tx) . . . the RF Stage trimmers only affect the Rx.

    Many thanks to KB3GWQ for editing and re-posting some of my advice from various threads on here . . . at some point I will create a proper page on my website with FT101 advice (and make some of the instructions a bit more clear)!

    Roger G3YRO
    W1BR likes this.
  4. KE4CQ

    KE4CQ Ham Member QRZ Page

    Thanks, Roger!
    A spreadsheet type doc showing each band and corresponding trimmer ID would be awesome to have using your procedure! Looking forward to getting mine done...

    Last edited: Aug 10, 2018
  5. G3YRO

    G3YRO Ham Member QRZ Page

    The whole way the Handbook describes aligning these circuits is absurd !

    It would make sense if you had just built the rig, or replaced ALL the coils etc . . . but normally you DON'T want to touch ANY of the coils . . . just peak the Preselctor on each band on Transmit for max drive . . . and then leave it that position and peak each of the trimmers, band by band.

    (all you're doing is very slight adjustment to allow for ageing, and/or new Driver or PA Valves.)

    Roger G3YRO
  6. N2EY

    N2EY Premium Subscriber QRZ Page

    When you say "Handbook" - do you mean what would be called an "instruction manual" on this side of the pond?


    Here's another possible trick:

    The FT-101 family uses 6JS6 finals, but can easily be modified to work with 12JS6 tubes by wiring the heaters in parallel (they are in series in the FT-101E family - check other models). However, if this is done, be SURE that the mod is documented somewhere highly visible on the rig, because if someone puts 6JS6s in the sockets, they will have a short life....

    31JS6 tubes can also be used, but the task is a bit more complex. The simplest way is to add an external transformer, fed through the accessory socket, to power the tube heaters.

    73 de Jim, N2EY
  7. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    You can get 6LB6 tubes for half the cost of the original tubes and they are a drop-in replacement. You just have to realign it slightly. Power output is not exactly the same, but pretty close. I get over 120w out on all bands after realignment. Don't fudge the radio up with different types of tubes that require changing a bunch of components and changing the wiring if you can help it.
  8. G3YRO

    G3YRO Ham Member QRZ Page

    To be honest, I've never had to use anything other than the Toshiba 6JS6C valves that Yaesu used (still have some brand new ones)

    Do the 6LB6s work as well on the higher frequencies? (I always presumed Yaesu chose the 6JS6s for a reason)

    Roger G3YRO
  9. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Yes, after you gave me the alignment procedures I can get at least 120w on 10m. I seem to get about 125-135w on 20-40-80. Rolls off more towards 120w or so on the other bands. Maybe you get a bit more on the originals, but I'd say 120w or so is pretty darn good. There's very little improvement I'd imagine on getting potentially 140-160w (or whatever it is stock).
  10. G3YRO

    G3YRO Ham Member QRZ Page

    No, stock is 130 watts maximum output on all bands except 10m, about 120 watts. (with an accurate power meter)

    So that's pretty good (and the difference is negligable)

    Roger G3YRO

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