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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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7th Apr 2019, 6:45 am | #1 |
Triode
Join Date: Apr 2019
Location: Nowra, New South Wales, Australia
Posts: 10
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Yaesu FT7 Dead on 20m
Trying to sort out an old FT7. It operates well on other bands except 20m. When switched to 20m I get the same as if I went to use a Fixed Crystal channel with no crystal in it. I am leaning towards replacing the 28.5Mhz crystal, however finding one seems to be a bit of a problem. Would anyone have any other ideas of what I should look at before trying to obtain another 7 for parts? Thanks in advance. Cheers
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7th Apr 2019, 12:14 pm | #2 |
Heptode
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 773
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Re: Yaesu FT7 Dead on 20m
Hi,
There's a chap here in the UK who advertises crystals occasionally in the classified Ads section of Radcom magazine and who I've heard good reports of. His e-mail is voyjako@gmail.com and I believe he is on ebay but I don't have his user name to hand. Hope this helps, Roger |
7th Apr 2019, 4:15 pm | #3 |
Heptode
Join Date: Mar 2008
Location: Newmarket, Suffolk, UK.
Posts: 612
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Re: Yaesu FT7 Dead on 20m
Also Quarzstlab wil make you a crystal
quartslab@aol.com Dave – GW4AKY QuartSLab www.quartslab.com Email: sales2@quartslab.com Tel. 020 7100 6357 Mobile: 07496 177 157 73 Fred G4BWP |
7th Apr 2019, 9:09 pm | #4 |
Rest in Peace
Join Date: Feb 2004
Location: Hexham, Northumberland, UK.
Posts: 2,234
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Re: Yaesu FT7 Dead on 20m
Might be worth checking the original crystal is working by trying to pick up the 28.5MHz signal radiated from it on a scanner or something similar tuned to the frequency. Could save you some trouble.
Alan. |
8th Apr 2019, 5:18 am | #5 |
Nonode
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,340
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Re: Yaesu FT7 Dead on 20m
If you have the service manual, page 22 will give you the test point (TP1901 on the Local unit) where you can measure with an RF probe for a 50mV signal in each band.
If you have no signal, then either the crystal is crook or it's associated trim cap is faulty (there can be other causes but they are the two most common). |
8th Apr 2019, 8:31 am | #6 |
Heptode
Join Date: Mar 2008
Location: Newmarket, Suffolk, UK.
Posts: 612
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Re: Yaesu FT7 Dead on 20m
If you dont there is a nice copy but for the FT7B here
http://www.radiomanual.info/schemi/Y.../FT-7_user.pdf 73 Fred G4BWP |
8th Apr 2019, 12:31 pm | #7 |
Nonode
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,340
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Re: Yaesu FT7 Dead on 20m
I've got the FT7 one but is too big to post here.
Let me know if you need a copy. |
8th Apr 2019, 1:31 pm | #8 |
Dekatron
Join Date: Jun 2016
Location: London, UK.
Posts: 3,687
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Re: Yaesu FT7 Dead on 20m
I'd ram another crystal (any old thing - 10mhz - 16mhz) in there and see if it works or not first. Might be another component in the oscillator. Old trimcaps are notorious for going wonky.
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8th Apr 2019, 4:14 pm | #9 |
Dekatron
Join Date: Jul 2008
Location: Charmouth, Dorset, UK.
Posts: 3,601
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Re: Yaesu FT7 Dead on 20m
I had this problem on 40m on an FT101 and it was a crystal failure.
Peter |