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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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28th Aug 2019, 7:25 pm | #1 |
Triode
Join Date: Mar 2016
Location: Uffculme, Devon, UK.
Posts: 17
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Yaesu FRDX400
My FRDX400 decided to burn out its mains transformer last week taking out the house mains trip at the same time.
Looking at the transformer it looks to be pretty well cooked with melted varnish that has seeped out and onto the chassis. Is there any one that has a spare (perhaps from a broken for parts) receiver? or possibly someone that can rewind/rebuild the existing unit? Any help gratefully received as I don't want to scrap what is a fine and (up to the meltdown!)clean radio for the sake of a transformer. I will be replacing most of the capacitors as suggested elsewhere, but can't see any other obvious reasons for the breakdown. PS I'm also looking for a 6M converter board for the unit as well assuming it can be fixed.. Thanks in advance Glenn (G0HPS) |
28th Aug 2019, 9:27 pm | #2 |
Heptode
Join Date: Jan 2008
Location: Birchington Kent, UK.
Posts: 595
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Re: Yaesu FRDX400
Hello Glenn
I think if you put this post in the 'wanted' section of the forum, one of our resident transformer rewind experts may be able to help. Wonder what the HT & LT current requirements are? You may be able to use a fairly standard transformer from another redundant piece of equipment.
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Regards Pete |
30th Aug 2019, 12:20 pm | #3 |
Pentode
Join Date: Oct 2005
Location: Hebden Bridge, West Yorkshire, UK.
Posts: 199
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Re: Yaesu FRDX400
Hi Glenn,
I had the same problem some years ago. Spent ages looking for a replacement transformer without success. Transformer failure seems to be fairly common with the Yaesu 400 family. Eventually I built an outboard power supply and put it in the cabinet I built to hold a speaker for the receiver and was quite satisfied with the result. Still a decent receiver in my view. Good luck
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Peter G8BBZ |
30th Aug 2019, 5:33 pm | #4 |
Heptode
Join Date: Mar 2008
Location: Newmarket, Suffolk, UK.
Posts: 611
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Re: Yaesu FRDX400
Repeating my previous advice on Facebook to contact Ed Dinning (Dining?) on this Forum for a rewind
Fred |
31st Aug 2019, 3:46 pm | #5 |
Heptode
Join Date: May 2015
Location: Bradford, West Yorkshire, UK.
Posts: 510
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Re: Yaesu FRDX400
Same here, I mentioned Ed on Facebook as well, you'll find him on "services offered"
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worried about the electrons entering the circuit and the smoke leaving Andrew |
31st Aug 2019, 5:15 pm | #6 |
Heptode
Join Date: May 2015
Location: Bradford, West Yorkshire, UK.
Posts: 510
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Re: Yaesu FRDX400
It's a monstrous iron lump, rated about 500W or so, multiple taps for 800v, 300v, 150v, + others.
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worried about the electrons entering the circuit and the smoke leaving Andrew |
31st Aug 2019, 5:48 pm | #7 | |
Heptode
Join Date: Jan 2008
Location: Birchington Kent, UK.
Posts: 595
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Re: Yaesu FRDX400
Quote:
Output from the transformer appears to be: 6.3v (about 3A) 13v ( supplying a few transistors) 200v . The spec. states 50w power consumption from AC mains. On that basis, the current requirement doesn't seem particularly huge.
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Regards Pete |
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31st Aug 2019, 8:11 pm | #8 |
Nonode
Join Date: Jun 2013
Location: Surbiton, SW London, UK.
Posts: 2,801
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Re: Yaesu FRDX400
Yes it's only a receiver, not the FTDX400/500 transmitter which does have a large transformer, so HT 200V @ 100mA should suffice.
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1st Sep 2019, 11:43 am | #9 |
Heptode
Join Date: Mar 2008
Location: Newmarket, Suffolk, UK.
Posts: 611
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Re: Yaesu FRDX400
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1st Sep 2019, 1:11 pm | #10 |
Heptode
Join Date: May 2015
Location: Bradford, West Yorkshire, UK.
Posts: 510
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Re: Yaesu FRDX400
ooopps, should have read the question properly re FRDX not FTDX
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worried about the electrons entering the circuit and the smoke leaving Andrew |
1st Sep 2019, 4:25 pm | #11 |
Octode
Join Date: Feb 2009
Location: Bletchley, Buckinghamshire, UK.
Posts: 1,205
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Re: Yaesu FRDX400
I have used a couple of these receivers and noticed that the mains transformers ran extremely hot. I wonder if they were originally designed, and "value engineered" for 60 Hz mains supplies?
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1st Sep 2019, 4:37 pm | #12 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
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Re: Yaesu FRDX400
Could be - though remember that in Japan part of the country has historically been 50Hz and another part 60Hz so I guess they'd have designed to tolerate the frequency-spread.
Also looking at the schematic the primary is two windings rated for 117V which are wired in series to get 234V-compatibility. Here, the mains is never below 245V and during the day can go up to 252V - which would significantly stress a designed-for-234V setup. |