Yaesu FT-840 help needed
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Yaesu FT-840 help needed
Hi guys i have a Yaesu 840 and when i turn power up above a certain level around 30 watts sometimes the tx power goes to 0 as i'm transmitting. SWR is fine and tried with a dummy load and still happening. It is a intermittent problem. Does anyone have any idea what could be causing it ? Also the signal meter on FM isn't sensitive enough is there anything i can change to make it better ? Everyone gives the same signal more or less unless they are close by me.
- Buick Mackane
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Re: Yaesu FT-840 help needed
Not familiar with the radio in question but i'd suspect a dry joint on the PA board, And there should be an adjustment for the FM RX meter
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Re: Yaesu FT-840 help needed
Nice radio but i've come to the conclusion there are too many design flaws. The Radio is now blinking and only stops when i go to the lower hf bands. Shame as i love the meter on this radio.
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Re: Yaesu FT-840 help needed
Just looked online, It's an older model, So not loaded with SMT and processors, So chances are it shouldn't be too tough to repair, I guess from looking at it it dates from the 90's, So probably needs a few electrolytic capacitors replaced.
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- Buick Mackane
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Re: Yaesu FT-840 help needed
I Dunno if nick black spirit repairs amateur gear, Only one way to fine out, Ask him 

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- Auldgeek
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Re: Yaesu FT-840 help needed
He doesn't unfortunately. Dave Woods or Geoff Castle would be my choice,Buick Mackane wrote: ↑11 Sep 2022, 13:17 I Dunno if nick black spirit repairs amateur gear, Only one way to fine out, Ask him![]()
Auldgeek - Drew
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I've changed radios so many times, I've forgotten what I have
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- ch25
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Re: Yaesu FT-840 help needed
Maybe meter is lazy because low signals incoming? Did you measure RX sensitivity?
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Re: Yaesu FT-840 help needed
Hi there i checked with a few other radios and it's only this radio. It is very lazy and hardly any difference between most signals.
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Re: Yaesu FT-840 help needed
Proper way to do it:
Or use external transmitter and try to adjust.You do not have the required permissions to view the files attached to this post.
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Re: Yaesu FT-840 help needed
Maybe i didn't explain myself clearly. On my other rigs there is 3 s points difference between 2 people,now the same people on my yaesu 840 give me the same signal or maybe a needles width difference. This only happens on fm.
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Re: Yaesu FT-840 help needed
So it sounds like FM path issue, not s-meter itself.
Chris
Chris
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