FT-101E Intermittent Audio level/S-Meter level

Discussion in '"Boat Anchor" & Classic Equipment' started by KB3GWQ, Jun 26, 2018.

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  1. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Well, looks like I spoke too soon now the thing is really quiet again and it's not the bulb or RF ATT switch. Even the tone generator is pretty much S0 on the meter. I'm really not sure what's going on here. I don't think it's that transistor because if I remove that transistor then there's no 25/100 tone tester working and I can't hear any signals just noise.
     
  2. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Did some testing on the fet with some probes and G1 is reading 12V instead of 1.9V. I can't test G2 just dont have a probe long and narrow enough but the others are close within spec I would think. D is about 12-13V. S is about 3.3V. I think this would normal for a rig this old. So now what?
     
  3. G3YRO

    G3YRO Ham Member QRZ Page

    OK . . .

    Based on your symptoms, I doubt very much whether you have an actual component or device fault.

    I presume you cleaned the edge connections on the RF Board?

    Does this happen the same on all bands?

    If so, I would unplug the 2nd IF Board (the one with the crystal filters on) and clean the edge connections . . . and if that doesn't fix it, do the same on the 1st IF Board - the one in the can in the middle of the rig.

    (All these plug-in boards should all be given a quick unplug and clean every 5 years . . . chances are it's never been done)

    Roger G3YRO
     
  4. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Hi Roger,

    Yes, this problem is the same across all bands. I can try cleaning the card edge connectors on the 1st and 2nd IF boards. Maybe it is the one in the can. I have never removed that board. I actually didn't know there was a PCB inside it.
     
  5. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Roger, just removed and cleaned both boards and it made no difference. Right now I'm listening to a 599 CW signal on 40m and it's peaking at like S2-S2. I didn't screw down the 1st IF board in the can back down and if I wiggle it there's a little bit of microphonics but doesn't change anything. Rocking the ALC/BM board with the 3 80m crystals on it doesn't appear to make any difference.
     
  6. KA9JLM

    KA9JLM Ham Member QRZ Page

    A good starting point, Is to measure the power supply voltages.

    I think that radio has 3 main supply voltages. Look at ripple voltage on them.

    Then you can go from there.

    Have you cleaned the band switch ?

    How does a S2 get a 599 report on CW ? :rolleyes:

    Good Luck.
     
    Last edited: Jun 28, 2018
  7. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    What I mean by 599 (I can't tell if you're just being funny here) is that normally it would be a whopping 599 real loud on any other rig, but looking at the S-Meter it's only hitting about S2 and the volume output is low when the knob is maxed out.

    I have not cleaned the band switch, but I'd be surprised if this was the cause as I did try rotating through the whole thing multiple times to see if that affected it and it doesn't. I know the S-Meter works as well because I can transmit and tune-up just fine. So we know the preselector knobs and friends are working OK too. There is a 10uf 50V electrolytic inside that 1st IF that I never knew was in there, but I'd doubt that would have anything to do with this problem. Looks like it could be real fun to change it hi. I did remove the side cover to that can and the joints all look OK. There's a little bit of browning in the big spots where they soldered the tabs but it doesn't look real bad. I can do a continuity test but I don't think this is the problem either.
     
  8. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    One of the pins on the 1st IF can (on the card edge SOCKET on the rig itself) has a little bit of green corrosion on it. I didn't do anything to it as Roger said these are supposed to be gold(?) contacts if that's the case I may end up making it worse later on. Maybe cleaning this would be a start though. Forgot to mention that I did do a quick check with a flash light to make sure there wasn't something stupid like a solder blob, stray thin wire debris, "tin whiskers", etc. on it.
     
  9. G3YRO

    G3YRO Ham Member QRZ Page

    OK . . . well the last board in the signal path is the Noise Blanker . . . so try unplugging and cleaning that.

    Odd to see any corrosion on the gold contacts, but you could try gently scraping that green with a tiny screwdriver (watchmaker's size)

    It won't be the power supply . . . there's a 13V unregulated supply that supplies everything except the VFO, which has a 6V regulated line. If the receiver is basically working, and especially as the Tx is working, that's not the problem.

    It COULD simply be a bad connection on the bandswitch . . . as the Tx is OK, it will only be the wafer that connects to the front end Rx Trimmers. They used solid wires, so you CAN end up with a broken solder joint on the switch that is just touching like a cat's whisker (and hence intermittent). So check that - in fact re-solder the Common wire that goes to the coil anyway.

    Roger G3YRO
     
  10. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Roger,

    OK. Will check these things out. Also, I'm guessing it is NOT related to the Antenna Relay? I did take that out a few days ago and clean the contacts and put it back in there, but didn't notice a difference.

    By the way, the problem is no longer intermittent it is now permanently much quieter.
     

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