Yaesu FTDX-400

Discussion in '"Boat Anchor" & Classic Equipment' started by AF6LJ, Aug 18, 2011.

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  1. AF6LJ

    AF6LJ Ham Member QRZ Page

    I don't know why I have this thing for old rice boxes, but I do.
    The Tempo-One was a good example of how cheap can our friends across the pond build a radio and still work. And it does work reasonable well, after an hour warm up. :)

    A while back I had the chance to acquire a non working FDDX-400 I remember reading reviews of this radio and wondered how well they preformed. Well here it is forty years later and I have one heating up mu room.

    The radio came well packed and I must admit I was a little surprised how heavy it was.
    After opening the radio the first thing I noticed was there are no tube shields, so that is on my list of things to acquire. Next I noticed there is no PA shield, I'll have to get or make one of those also. Well with that out of the way time to grab my headphones and fire it up to see just how much work there really is to get this radio back on the air.

    At first all I could hear was a weak calibrator signal, no pre selector setting would improve things.....
    Well after several tests on each band I found that the bandswitch knob was three positions off. Reindexing the switch fixed that and with nothing more than my IFR I verified the receive on all five bands. An actual sensitivity measurement on seventy five gave me a receiver sensitivity of about a microvolt for ten DB.....
    The S-meter was zeroed and it was time to see what was going on with the transmitter...

    The transmitter didn't fair so well.......
    While I have a good functional exciter, and I get useful drive at the grids of the two 6KD6s (30VPP) there is something very wrong with the PA. Could be tubes but I am not going to jump to t6hat conclusion just yet.

    First thing that needs done is to go and download a manual. There are three versions of this radio, thankfully I have a gift for being able to figure things out with a minimum or even partially correct documentation. That skill will be pressed into service on this radio.



    While I was taking a few photos I happened to notice something
    As can be seen above there is a brown wire that has been unsoldered and capped with heat shrink tubing. Well a few resistance measurements later and a quick power on test revealed that someone had disconnected the high voltage secondary terminal from the transformer.
    Well that explains why there is no PA output. :)
    The radio has a proper fuse so the next step will be to give it a smoke test.

    More to follow for now I have other things that need my attention.

    Stay Tuned...
  2. W5WPL

    W5WPL Ham Member QRZ Page

    Looking furd to seeing hot dawgs grillin on the top of that thang
  3. AF9J

    AF9J Ham Member QRZ Page

    It didn't take you too long to find things I missed on it. As I told you ages ago, don't be surprised if you have to use that spare set of 6KD6s you have. The guy who sold it to me at the swapfest a couple of years ago, told me that the finals were weak. I'm glad to see you've got the radio running better than I did. :) As I told you, don't trust the BAMA manual - it's for a different mark/version of this radio. I found out on a website, that there were 4 marks of the FTdx-400. From the photos I looked at, it seems to be the Mark III version:


    Good Luck, and have fun with it Sue! :)

    Ellen - AF9j
    Last edited: Aug 18, 2011
  4. WA7KKP

    WA7KKP Ham Member QRZ Page

    If you didn't know, the FTDX-400 and the Tempo-1 are both Yaesu products. Henry Radio just contracted to have the Yaesu FT-200 built with the Tempo name on it.

    Your rig is one of the chrome plated tube transceivers that Yaesu first penetrated the US ham market (look at the FTDX-560 and the 401 to see the family resemblance. Put a whisper fan on it to keep the boards cool; heat was the major destroyer of those PC boards.

    The disconnected HV lead makes me wonder if a CBer might have tweaked it. Check the hetrodyne crystals for 10 meters and make sure they are correct for 10 meters.

    Gary WA7KKP
  5. AF6LJ

    AF6LJ Ham Member QRZ Page

    The good news is; the radio didn't go up in smoke when I connected the brown lead back up to the transformer. The not so good news is on some bands the radio puts out ten watts on others it puts out maybe fifteen watts. And in other news it looks like based on the link you provided Ellen and a little other information I have scrounged up I'll be using a 400 and a 560 manual as a guide for any repairs needed.
    The FTDX560's board layout resembles the radio more than the MK-1 FTDX400 manual.

    Oh and the other good news......
    It looks like little if any tweaking was done on the main board the inspection paint is still intace on most all the coils that have protruding slugs.
  6. W5WPL

    W5WPL Ham Member QRZ Page

    Hey!!! I made a funny
    And you didn't say anythang.
    I want sum atentshun
    I want sum atentshun

    no bodie loves me.
  7. AF6LJ

    AF6LJ Ham Member QRZ Page

    It should do that just fine.
    My Tempo-One has a warming function for hot dogs. :D
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I LOVED the FTDX-400. I had one when it was new and I thought it was a "great" rig, at the time (it was).

    Get it going, Sue, you're on the jazz.

    It'll blow the doors off a Tempo-One -- way better rig in many respects.

    I think it's a "classic," as is the FTDX-560. Back then, there was a "war of Watts" going on to see who could push sweep tubes harder.;) Drake was conservative with them, but many others just went full-blown nuts.

    At the same time, Heath and Collins just stuck with 6146's and rated them at 160W PEP "input" power, which was about 100W PEP output. But I sure remember the Watts Wars between Swan, Yaesu, Hallicrafters and a few others...

    JA1MP would be proud.
  9. AF9J

    AF9J Ham Member QRZ Page

    Told you the sweeps were bad! ;)
  10. AF6LJ

    AF6LJ Ham Member QRZ Page

    Speaking of watts wars....
    One of these days I'm going to get my hands on a 500CX.
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