Yaesu FT-840 help needed

[LondonCbRadio]

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]

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

[LondonCbRadio]

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.

[Buick Mackane]

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.

[LondonCbRadio]

Thanks mate i'll keep trying until i get there.

[Buick Mackane]

I Dunno if nick black spirit repairs amateur gear, Only one way to fine out, Ask him

[Auldgeek]

I Dunno if nick black spirit repairs amateur gear, Only one way to fine out, Ask him

He doesn't unfortunately. Dave Woods or Geoff Castle would be my choice,

[LondonCbRadio]

Anyone have any idea on how to make the meter more sensitive ?

[ch25]

Maybe meter is lazy because low signals incoming? Did you measure RX sensitivity?

[LondonCbRadio]

Maybe meter is lazy because low signals incoming? Did you measure RX sensitivity?

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.

[ch25]

Proper way to do it:

840.jpg

Or use external transmitter and try to adjust.

[LondonCbRadio]

Proper way to do it:
840.jpg

Or use external transmitter and try to adjust.

I've done that and it's still the same.

[LondonCbRadio]

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.

[ch25]

So it sounds like FM path issue, not s-meter itself.
Chris

[LondonCbRadio]

So it sounds like FM path issue, not s-meter itself.
Chris

Yeah i agree. Is there a solution ?