Ft101e someone modified the n.b. board. What is this?

Discussion in '"Boat Anchor" & Classic Equipment' started by KG7HVR, Dec 25, 2018.

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  1. KG7HVR

    KG7HVR Ham Member QRZ Page

    I got this radio in a trade. Seems to work good but the noise blanker is terrible on the 10m band. I did some investigating and found that the noise blanker unit has been modified.
    I swapped out the pb1292 board from my 101 Bravo and it works a lot better. A interesting thing to note when the noise blanker isn't even on with the other board it's quieter then the modified board. then when you turn it on it's even more quiet. this modified one does work but it doesn't work as good in either radio. Here are some pictures of the board. a trace has been cut, a jumper has been added and it looks likely at one point cut another teace and two resistors have been added. I don't see where the diode has been changed that people were talking about online. I can't really find any information on this modification on the internet.
    73 all
    Happy holidays. 20181224_172010.jpg 20181224_172018.jpg

    Attached Files:

  2. KG7HVR

    KG7HVR Ham Member QRZ Page

    No one?
  3. G3YRO

    G3YRO Ham Member QRZ Page

    There were LOTS of modifications to the Noise Blanker circuit across the different FT101 models . . .

    Some of those will include extra wires or components on the back of the PCB too . . . so it's likely the modification you have shown was done at the factory by Yaesu during production.

    The very last of the original FT101 series, the FT101F, even converted the 3.180 MHz IF frequency on the Noise Blanker board down to 455 kHz for some reason !

    Also bear in mind that most FT101Fs sold outside Japan were still badged as FT101Es . . . so I have an FT101E and an FT101F, although both say FT101E on the front panel !

    Anyway . . . coming back to your question, what do you mean when you say that the board is "terrible" on the 10m band?

    Bear in mind that the FT101 was designed as a Mobile rig . . . so these Noise Blankers were only EVER designed to take out short pulse interference - like you get from interference from vehicles' spark plugs. (igntion noise). They are brilliant at completely removing that, even if it's VERY strong. However, they WON'T do anything to reduce ordinary electrical or band noise.

    Roger G3YRO
    W1TRY, WA7PRC, W7UUU and 1 other person like this.
  4. KG7HVR

    KG7HVR Ham Member QRZ Page

    How do I tell if mines a F model?
    These mods look sloppy to me.
    The board in my 101B has the same number on it but is silver not copper in color. It works better. Is it possibly the older IF 3.180mhz ?
    After careful adjustment I got it to work better. Its still doesnt compare to the unit from my 101B.
    On 10m i get alot of noise. Just steady noise not really anything impulse. With the 101b board mostly its gone.
  5. W9GB

    W9GB Ham Member QRZ Page

  6. K7MEM

    K7MEM Ham Member QRZ Page

    I can agree with that. I worked for 5 years in a production test area. A change like that would have never made it out of the test area. There is a capacitor on the board that appears to be factory installed.
  7. G3YRO

    G3YRO Ham Member QRZ Page

    To be an FT101F, it would have ALL THREE of the following:

    1. A Speech Processor board with a front-panel output level control around the clarifier (PB1534) (earlier versions just had a pre-set on the board)

    2. A Crystal Calibrator that DOESN'T use a tall 100kHz crystal. (PB1547)

    3. A Noise Blanker that has a conversion crystal osc that converts the noise signal down to 455 kHz. (PB1582)

    If it has LESS than all three of the above, I guess it's an FT101E . . . but if it has ALL THREE then it's really an FT101F (even though it's probably badged as an E.)

    Regarding your noise comparing your two Noise Blanker boards, are you saying that ONE of the Boards reduces the noise when the NB is switched on, but the other one doesn't? If so, have you tried adjusting the pre-set on the top?

    Also, have you checked that both of these boards are working the same with the NB off . . . i.e. using the Calibrator as a reference signal, is it the same strength on the S Meter with EITHER board plugged in?

    Roger G3YRO
    Last edited: Jan 3, 2019
  8. KG7HVR

    KG7HVR Ham Member QRZ Page

    Ive been through all that. They are same board number but ones copper ones solder color
  9. KG7HVR

    KG7HVR Ham Member QRZ Page

    It has that processor at least. Have to check the rest.
    The boards do sound different with the nb off also. They both are a pb1292
    The earlier one works alot better. I adjusted the other and its better but not as good.
  10. G3YRO

    G3YRO Ham Member QRZ Page

    Yes it's strange how the finish on the boards vary . . . some have all the copper tinned, on both sides of the board.

    Others leave the copper bare on the top, but covered in green lacquer on the bottom.

    But they vary between the two, regardless of how old the rig is ! So, for example, you will find FT101Bs with both styles of boards, the same with FT101Es. (But normally the same style of board throughout each rig, unless they have been replaced)

    Personally I prefer the all-tinned style, as they're easier to work on (that's what my FT101E has)

    Roger G3YRO

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