Manual yaesu ft 840

Which model headset for yaesu ft840

3 Related Answers

Anonymous

298 Answers
Posted on Dec 23, 2007

you have an oscillsocope to see the
signal imposed on the output signal.or
are you talking about sound(hum)
AC line interference is usually
power supply filter caps or
output filter caps or bad
ground (ground loop)
1 check grounds
2.check for bad antenna cable
3.check power & output amp filter capacitors

Anonymous

1 Answer
Posted on Mar 28, 2009

SOURCE: yaesu Ft 2200 transceiver operators manual

Found a couple of ham radio sites that had manuals for sale or free downloads. Took several hours on net to find but it worked. had at lest 3 responses in 24 hr period of time.

thanks for yur help.

Jiri Klima

44 Answers
Posted on Dec 07, 2011

SOURCE: AC line interference

I experienced very similar or the same problem with FT-840. When power is inceased over about 50 W, an AM on RF signal arises. Even when TCVR is supplied from accu and connected to dummy load. Period of interferencing signal is about 7.5 ms (130 Hz), so it cannot be hum from mains. I have not opened the PA block yet but i guess, it could be caused by damaged capacitor(s). Jiri

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My Yaesu FT-840 tuning knob turns, but the frequency does not change can you help?

Question edited for correct spelling of Yaesu and correct forming of model number.

There is a service manual here, but you would be better to take to a service centre unless you are very skilled with electronics. It has a Lithium backup battery, and I think I would change that at the outset.

https://www.radioamatore.info/attachments/195_FT840_serv.pdf

https://www.google.com/search?q=yaesu+ft+840+service+manual

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