Yaesu FT-101E Intermittent Transmit

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

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  1. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    On my never-ending journey with this FT-101e... it's been working good for a while now thanks to Roger, G3YRO... but now what happens is when I transmit power output will be 0 for about 5-10 seconds and if I continue holding it in then the power comes back. It's not the relays as I cleaned them and they were cleaned a few months ago. It's not the carrier knob as I tried moving it around a lot and sometimes the transmit problem will try and go to where t needs to be and bounce back to 0 multiple times when this happens if I move the carrier it will "peak" at where it's resting.

    I tried cleaning the pins on the driver tube and rocking it, etc. and it's not that either. It's not band specific so we can rule out the trimmers on the bottom of the board. It's not Tune/CW/AM specific either. I tried rotating the mode and band switches many times while it's going on.

    My guess at this point would be a solder joint or component that is going bad in the HV cage that is exposed to the high temperature?
  2. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Okay. So I took the whole thing apart and cleaned the actual tube sockets and pins (and the top pin not sure what this is called?) on the final tubes and also cleaned the 12v relay socket (cleaned that relay itself last week) by using a kebab skewer with some deoxit on it. The pins were all coming up black and one of the tubes was kind of loose when I took it apart. So far, it's holding the power properly now. I also noticed now I'm getting 125w instead of 100w out now that I cleaned these things in the HV cage.

    Did a quick inspection around all the stuff in and below the HV cage (with covers off) and didn't see anything really scary. So maybe it was just the one tube being loose and pins being dirty? Will update again after I've left it on for an hour with heaters on and doing some CW work.
  3. G3YRO

    G3YRO Ham Member QRZ Page

    OK, cleaning the Valve Pins is no bad thing, if they looked tarnished . . .

    However, completely losing Tx output is FAR more likely to be something early on in the transmitter circuit, rather than something at the end (like the Output Valves).

    I know you said you previously cleaned the main Tx Relay contacts . . . but 99% of problems on these rigs is due to dirty relay contacts.

    Worth taking the relay apart and doing it again. Use postcard-thickness card, cut into strips, and soaked in switch cleaner. Press the relay contacts together as you drag the strips between the contacts several times on each pair, and certainly until all traces of black stop coming off.

    Roger G3YRO
  4. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Well, the relay I cleaned today was the one by the VFO. And even after that it made no change. I cleaned the "Antenna" relay last week during the whole intermittent RX problem. So far rig is still working made a few contacts, but will keep you posted.
  5. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    OK, well I just did the SKCC CW club's weekend-sprint for the past 2 hours and it was fine. This was without the main gray covers on, put them back on so I guess we'll find out if it's still good a little later. I guess the combo of cleaning the pins, sockets and reseating everything fixed it.
  6. HAMHOCK75

    HAMHOCK75 QRZ Member

    G3YRO may disagree but I found cleaning RL1 every month a bit much. The problem is that there is no way of knowing whether a previous owner cleaned it properly or improperly. I replaced it with a different relay that required some rewiring as described in the Fox Tango site. Never had a problem since.
    Last edited: Jul 9, 2018
  7. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    I'm not so sure it was relay. I really think it was something with the tubes just needing cleaned and reseated. But, who knows. I'll keep it in mind for the future though if/when the time comes with replacing the relay.
  8. G3YRO

    G3YRO Ham Member QRZ Page

    I have never suggested that !

    But it is certainly worth giving it a proper clean every 5 years, if you want trouble-free operation of your FT101.

    The problem is that if you buy a secondhand rig, it may NEVER have been cleaned . . . so cleaning it PROPERLY can take some time (and what I was suggesting to the OP was that although he said he had already cleaned it, it might still be causing a problem if it hadn't been done well enough)

    Anyway . . . let's hope the intermittent Tx fault has gone now.

    Roger G3YRO
  9. HAMHOCK75

    HAMHOCK75 QRZ Member

    You did not suggest that. I had to do it every month because it would fail in the middle of a QSO every month. It was always the same set of contacts too. These relays have been out of production for some time so replacements are rare although not impossible to get. I decided that to replace with a new relay since there was no way of knowing how a used replacement rely might have been treated.
    KB3GWQ likes this.
  10. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Lol, sorry to hear it was literally a monthly thing. I notice that pots get intermittent if you only CLEAN them but don't apply any lubricant afterwards. But, it sounds like you know what you're doing so I assume you were also using lubricant to protect it from flash tarnishing again. In that case, then yeah unfortunately it would have to be replaced and you're right you'll never know if the previous owner took sandpaper to it and ruined it.

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