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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

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Old 20th Jan 2018, 7:06 pm   #1
Chris 1155
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Default Yaesu FT290R. Deaf Receiver.

I have a problem on my FT290r.
It works well on all function including TX but the receiver has gone deaf.
It will receive a local ie in the room signal from a handheld and open the squelch and give audio.
It will not respond to a strong external signal even when connected to my collinear. It is not a squelch problem as this is set wide open.
I suspect a RX front end problem but do not know where to start.
Does anyone have any guidance or suggestions?
Regards
Chris G4BYZ
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Old 20th Jan 2018, 8:25 pm   #2
David G4EBT
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Default Re: Yaesu FT290R. Deaf Receiver.

Given that it was such a popular rig, faults have arisen over time and many have been well documented, as here:

http://www.whelan.me.uk/radio/mods290i.htm

The only relevant comment to your problem that I can see is this:

"No Audio Output: Check audio IC Q1027. Also check to see if the reverse polarity diode is blown, as reverse polarity causes failure of this IC".

That fault is repeated on other sites, such as MODS DK:

https://www.mods.dk/view.php?Article...on-the-FT-290R

Harold Leeming, who ran a Yaesu dealership, (long since retired), occasionally writes a column on rectifying common faults on the 290 and other equipment in PW, is the acknowledged expert of the FT290, so other users on the forum may have info on the FT290 topics that he's covered over the years.

Good luck with it Chris.
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Old 20th Jan 2018, 9:07 pm   #3
G6Tanuki
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Default Re: Yaesu FT290R. Deaf Receiver.

Does it show signs of any 'mods' done to it? The FT290 was a popular target for front-end twiddlers.

"Mutek" front-ends were generally worth sticking with; there were other front-end mod-boards that you should run-away-screaming from.

Modified or not, I'd be checking the diodes in the TX/RX switching stage. If these have gone 'soft' they could be strapping the transmit PA across the receive-input and causing significant desense.
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Old 20th Jan 2018, 9:14 pm   #4
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Default Re: Yaesu FT290R. Deaf Receiver.

It may be worth checking to see if there are any protection diodes across the Rx front end (I am not familiar with the circuit of this particular rig). These are normally two diodes connected in reverse parallel across the input of the receiver, the idea being that if a nearby transmitter stuffs too much RF into the aerial it limits the power reaching the front end. In extreme cases they go short and this can effectively short out the signal path to the receiver. It was a common problem with CB sets so may be worth a check if the 290 uses the same protection. I presume there are no Tx/Rx changeover relays in that set as they can also be a source of trouble. Maybe the front end RF amp transistor has failed? Check power rails for correct voltages to front end too.
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Old 21st Jan 2018, 2:42 pm   #5
Chris 1155
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Default Re: Yaesu FT290R. Deaf Receiver.

Thank you all for your very helpful replies. I will post a message letting you all know how I get on.
G4BYZ
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Old 22nd Jan 2018, 11:54 pm   #6
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Default Re: Yaesu FT290R. Deaf Receiver.

Yes please do; there are a few owners around, so it's of interest.

B
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Old 19th Feb 2018, 7:38 pm   #7
Chris 1155
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Default Re: Yaesu FT290R. Deaf Receiver.

I have now got the 290r working very well thanks to a lot of help and advice. The actual root problem was that there was a component missing on the RF front end.
Once this was replaced the radio worked well.
I then decided to fit a CTCSS module to allow repeater access. The modification was as described in Practical Wireless February 2018 issue. Also see https://billington repairs.wprdpress.com/modifications/cttcs-for-the-yaesu-ft290r-mk1 .
During this modification I caused some damage to the internal power supply but managed to resolve this. After this I discovered some dry joints von the control board and once repairing these the radios up and working very well and I have had many contacts both on simplex and using repeaters.
I now have an FT 790r and plan to fit a CTCSS module to this. I am not sure where to inject the tone signal and wonder if anyone has an opinion or experience on this.
Any help very welcome.
I will post results.
73 Chris G4BYZ
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Old 19th Feb 2018, 11:55 pm   #8
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Default Re: Yaesu FT290R. Deaf Receiver.

Hi, normally inject the tone on the centre leg (ie wiper) of the deviation adjustment potentiometer. 73 Paul m3vuv
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Old 20th Feb 2018, 1:56 am   #9
Bazz4CQJ
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Default Re: Yaesu FT290R. Deaf Receiver.

Chris, the link you gave in Post#7 is not working. Wonder if you could post correct one?

B

postscript; ok -got it!
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Old 20th Feb 2018, 11:45 am   #10
Chris 1155
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Default Re: Yaesu FT290R. Deaf Receiver.

Sorry the link is
https://billingtonrepairs.wordpress....esu-ft290r-mk1
If this does not work just search 'ctss for ft290r' and this site should come up in the results.
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