Ham Radio - Yaesu FT-991 finals replacement repair

Поделиться
HTML-код
  • Опубликовано: 29 окт 2024

Комментарии • 91

  • @cuban9splat
    @cuban9splat 7 лет назад +14

    When you changed to CW mode, the frequency jumped down to 3.499 which is below the 80 meter band. I think that may be why you had no output on 80 meters during the preliminary testing. My FT-950 does the same thing. It has not been opened up to transmit outside the ham bands. Great job on the repair! Thank you for sharing it with us. 73 DE K7RMJ Frank

    • @loughkb
      @loughkb  7 лет назад

      +cuban9splat I mentioned this in the description. I tested before filming, and had bumped it when I did the second pass for the camera..

    • @tonyatnb
      @tonyatnb 6 лет назад

      I saw that too.... but think he my realize it eventually,,,,I still stumble on that once in awhile.
      I like the band stacking storing parameters for each stacked memory

    • @ericlessard6653
      @ericlessard6653 6 лет назад

      Agree 3.499 does work unless mars cap was done so why show this

  • @chucknelson1676
    @chucknelson1676 5 лет назад +3

    Thank you very much for this video. Recently one of the finals in my FT-991 failed, which I noticed when I failed to get into a local UHF repeater. This video helped a lot to assure me that doing the task wasn't too difficult. Fortunately I have access at work to a good quality de-solder station with suction and getting the part out wasn't too difficult though getting sufficient (but not too much!) heat on it to pull up the transistor wings once the solder was all removed was difficult I should have initially left a little more solder on the connection to help with getting heat to the pad. I chose to replace only the failed part and so far that has worked out well. I was able to balance the bias very closely between the old and new part. You are very correct about the adjustment being very touchy. It appears consensus on the correct working value is 950mA each and I was able to easily set that. The initial room temperature value on the one working device was 1.7A so if the failed one was similar this shows why it failed. Back to full power and getting good signal and audio reports so I think the surgery was successful. Thanks again! 73 NC7R

  • @clays5802
    @clays5802 4 года назад +1

    Very informative and interesting. Fortunately my 991 was one of the later serials. Good view of inside and finals.

  • @dougsmith4338
    @dougsmith4338 2 года назад

    Well after watching several times I think I'll take a stab at this and replace my finals. I have all the tools you showed in your video. It'll cast me 300 in change just to mail the radio. I just bought a new 991A to replace the bad unit. 😊

  • @johncliff5417
    @johncliff5417 6 лет назад

    Hi Kevin, Nice repair done there. I did a similar thing upgrading the output stage of a cb power amp some time ago. Ended up having to fit a large fan to sit on and over the cooling fins to keep the heat down. All worked out great I ended up with nearly 500 watts PEP out with the modification. I should have saved it for 10 m use. Got rid of all the cb stuff when I got my ticket. 73 de G0WXU -John.

  • @jeromegrzelak8236
    @jeromegrzelak8236 7 лет назад +2

    GOOD JOB i think now the rig will work for a long time if the swr is low great job on the bias adjust 73 kg6mn

  • @jeromegrzelak8236
    @jeromegrzelak8236 7 лет назад +1

    same with my rig 70 bucks used my mic ptt to key the rig put them in i found no heatsink compound on mine did add some on the new ones now the radio works tnx for the info kg6mn

    • @loughkb
      @loughkb  7 лет назад

      There was a very thin film of heatsink compound on the factory finals, very thin. I painted some compound on the new finals before installing so they had a very uniform coating.

    • @jeromegrzelak8236
      @jeromegrzelak8236 7 лет назад +1

      good the compound sb put on my fets are working very well i liked your repair looking foward to your other topics jg

    • @hectorpascal
      @hectorpascal 5 лет назад

      This may well be the result of Yaesu getting sub-boards made in China. The mechanical inspection there is not as good as in Japan. The transceiver is almost certainly electrically tested in Japan before final assembly, but things like no heat sink compound can easily be missed.

  • @dxhunter5277
    @dxhunter5277 Год назад +1

    Hello Kevin thanks for your video it is very helpful.
    I still have a question from which series number of the FT 991 was this error corrected by Yaesu?

  • @Starbuckin
    @Starbuckin 5 лет назад +1

    Thanks a LOT for this video! It encouraged me to swap out my own finals on my FT-991 instead of sending it off and I saved a ton of money. It was easy to do and it's nice that the F.E.T.Finals are so accessible and easy to swap out. Also easy to set the bias on the new Transistors to where they should be.
    Thanks again, SUBBED. -73 KJ4JAE.

  • @joelflam
    @joelflam 7 лет назад +3

    Kevin who ever hired you is NOT paying you enough

  • @MrAdy1306
    @MrAdy1306 6 лет назад +12

    Who else was shouting "out of band" at the screen !!

    • @justinhellyer8892
      @justinhellyer8892 4 года назад

      Lol I. It was making me so aggravated. The TX light is blinking of course its not putting out power

  • @keneley8055
    @keneley8055 7 лет назад +1

    love watching you at work its all very interesting you are a wealth of information

  • @OctavMandru
    @OctavMandru 2 года назад +1

    wait a minute, Yaesu has not issued a recall for these units? I was considering getting one 991A but I am glad I went the 7300 route

  • @matthewstravelers
    @matthewstravelers 5 лет назад +1

    Thank you for the video, it will be very helpful. In the tech manual, it says to disconnect the coaxial cables from J4001 (PA IN), then terminate J4001 with a 50-ohm resistor. However, they don't say what power rating the resistor should have. Did you do this step, and if so, what size resistor did you use? Since it's an input to the PA, I'm guessing it's precautionary and doesn't need much.

  • @ngemin1822
    @ngemin1822 2 года назад

    Hello Sir
    I bought Yaesu FT-911A and when i joined with battery DC directly. It power never open. Please help.

  • @stevemobile1
    @stevemobile1 2 года назад +1

    excellent well presented.....thanks

  • @puretoronto
    @puretoronto 7 лет назад +4

    Yaesu should be repairing all units with this issue at no cost.

  • @dougsmith4338
    @dougsmith4338 2 года назад

    can you read the power output with the ALC meter selected? I thought you would need the power setting.. I seem to have the same problem now with my 991 although I have used it now for 7 years.

  • @flatfrog69rr71
    @flatfrog69rr71 7 лет назад +2

    Hi-can I ask !
    did you put it on the tester and check its spectrum output before giving back to the costumer?

    • @loughkb
      @loughkb  7 лет назад +3

      No. Only because it seems to be such a common and well known problem that it was a direct fix.

  • @Hillbillyshakespeare
    @Hillbillyshakespeare 2 года назад

    I have one that will not power on. What do I need to look for under the cover?

  • @philnyc
    @philnyc 6 лет назад +6

    9:15 You omitted The most important aspect of filming how you are desolder the transistor. You don't have to talk while doing precise work, but don't skip on filming it because that is why ppl actually watch these vdos.

    • @Westy-1
      @Westy-1 6 лет назад

      philnyc its probably because he never done the work himself and someone else done it then started filming again saying he's replaced the parts himself. I meen why couldn't he have filmed it its not like he had to hold the camera and try and solder at the same time. As u said this is why people watch these videos in the first place, me included. It's annoying and a complete waste of time.

  • @pudiful
    @pudiful 7 лет назад

    Good video and good multimeter. I had one of those.

  • @keithryant5779
    @keithryant5779 Год назад

    On my ft991a I checked my finals after finding out that I was using a bad antenna for about a week. Each side was set to 1.2 amps and seemed to be working. The only thing I found that is different is I am getting 7amps out when testing both together instead of the expected 2.4amps. Would you know why it would be reading higher, maybe an incorrect setting on the radio?

  • @jeffdwyer6105
    @jeffdwyer6105 3 года назад

    Question : The manual says to remove the exciter cable and put in a 50 ohm resistor and tune each Final Bias to 1.5A , you are tuning to .800A , which is it ?

    • @loughkb
      @loughkb  3 года назад +1

      I thought I mentioned it in the video. I read from more than one radio engineer that the default 1.5A bias is too high and the finals run hot even at idle. The consensus of the articles was that around 800ma seems best.

  • @richardp5161
    @richardp5161 2 года назад

    Any suggestions for the best method of removing the mounds of solder on the finals without damaging the board or close by components?

    • @loughkb
      @loughkb  2 года назад

      I sucked most of it up with a de-soldering iron and then used solder wick for the remaining. I think I remember using the tip of a razor knife and heating the tabs while gently prying them up to get them released initially. Cleaning the pads with solder wick after.

  • @Hax0rZ1
    @Hax0rZ1 4 года назад

    This is not just a problem with the old model. I have a less then a year old ft-991a at Yaesu right now for a “pa” finals being replace and rebalanced. Smoked up my whole ham shack with electrical smoke. It’s a factory defect that they are definitely not dealing with and forcing consumers to send in their equipment to fix on warranty or not warranty for some people.

    • @NealBailey
      @NealBailey 2 года назад

      I just found out my like new 991A has a bad final too. going to be sending it off to get repaired. I'm not so sure that Yaesu fixed the issue completely with the newer models.

  • @propagating-radio
    @propagating-radio 2 года назад

    Great video! Thanks!

  • @jamesoleary8687
    @jamesoleary8687 4 года назад

    I have watched the video several time's , my Bias will not adjust, what am I doing wrong?

  • @carolmartin7042
    @carolmartin7042 5 лет назад

    Great repair. Thanks. Glen M

  • @scottgarvy
    @scottgarvy 2 года назад

    My rig is putting out about 21 watts on 2 meters with two watt meters. Have any idea if this is related?

  • @clivewi9103
    @clivewi9103 4 месяца назад

    tab with the cut oou is the drain, the tab opersit is the gate.

  • @raykiii
    @raykiii 7 лет назад +1

    Kevin, did you use a vacuum pump on all that solder or did you use wick or was there another option that was more scalpel accurate?

    • @loughkb
      @loughkb  7 лет назад

      I have one of those radio shack desoldering irons with the squeeze bulb on it. It took awhile!

    • @WaterWhiteTuber
      @WaterWhiteTuber 7 лет назад

      sold-a-pults work pretty good. you can get knock offs cheap enough. I usually throw them away after the tip cracks or melts (even though you can buy new tips). Tips are available in nylon or ceramic.

  • @gertkok2113
    @gertkok2113 7 лет назад

    Hi Kevin, I have a Yeasu FT1802E/M My transmit filters are kaput on it and I am battling to find the part number. Could you perhapse see if you can point me in the right direction. Thank you so much and keep up the awesome videos - Gert de ZS2GHK 73

  • @marcinmichigan2772
    @marcinmichigan2772 4 года назад +2

    Good advertising for IC-7300's :)

  • @johnhiggins4698
    @johnhiggins4698 7 лет назад

    Hi Kevin,
    Any experience with Yaesu FT-7100 Dual Band Mobile? Mine worked fine for years then suddenly began to distort VHF audio on transmit. Hmmmnnn....seen this before?

    • @loughkb
      @loughkb  7 лет назад

      +John Higgins no, sorry. Have you tried a different mic?

    • @johnhiggins4698
      @johnhiggins4698 7 лет назад

      Kevin Loughin Yep! Got abt 13 good years on it...not ready to consign her to "parts". Might try the somewhat delicate final transistor replacement K3478...Quite a solder pond! TNX for the quick reply. 73, John/N6VTS

    • @loughkb
      @loughkb  7 лет назад +1

      Get ahold of an ESR meter and check the electrolytics in the audio chain. You might have one failing.

    • @johnhiggins4698
      @johnhiggins4698 7 лет назад

      Good Morning! I just ordered one and should be able to make those checks...thanks for the suggestion!

  • @panzerdivizzion
    @panzerdivizzion 6 лет назад

    cool you fixed it.Any chance someone tx with wrong antenna?

  • @ericalbert6954
    @ericalbert6954 4 года назад

    Merci beaucoup l'Ami !!!

  • @joedebaer2265
    @joedebaer2265 7 лет назад

    I had the same issue on my FT991. Find out that one of the final stage have a short circuit between Gate and source (like yours). How many power out you get on 80m with 12,5 V after repair?
    btw Thank for the detailed video of the repair :)

    • @loughkb
      @loughkb  7 лет назад

      Thanks for watching. It gave a full 100W on all bands with the new finals and proper biasing.

  • @PachaTip
    @PachaTip 3 года назад

    Great VDO GOOD JOB

  • @kendellinger7473
    @kendellinger7473 6 лет назад

    Kevin, maybe you are paying more attention to making a video than watching what you were doing but in your testing phase you failed to notice that you had tried to transmit out of band and an un-modified ft991 won't do that. You may have replaced finals that were perfectly good.

  • @jeromegrzelak8236
    @jeromegrzelak8236 6 лет назад

    Anyone knows what yeasue charges for this kg6mn

  • @kg5pte
    @kg5pte 2 года назад

    This radio reminds me of the first-generation XBOXES with the processor ring of death. My warranty just expired on May 20th and Yesterday May 22 my HF transmit went out. This shack in a box is junk. I never buy another one or any Yaesu product ever again.

  • @ne2i
    @ne2i 5 лет назад +1

    they should have used a 10 turn pot for the adjustment.... cost cutting strikes again....

    • @loughkb
      @loughkb  5 лет назад

      Would have been easier by far.

  • @stevenlawhon3695
    @stevenlawhon3695 5 лет назад

    5w over? finals getting hot?

  • @M0WFC
    @M0WFC 6 лет назад

    It''s about time Yaesu stopped being so tight and stingy with the amount of solder they use.

  • @terryjohnson5925
    @terryjohnson5925 5 лет назад

    A great way the remove the RF transistor would be to use a Chip Quik kit ,it is mainly used for SMD Removal watch the video link below!
    ruclips.net/video/7kyaz4Zrd78/видео.html

  • @paulhealey2984
    @paulhealey2984 7 месяцев назад

    You missed out the most important bit of the video, which was the desoldering and resoldering of components.!!

  • @ericlessard6653
    @ericlessard6653 6 лет назад

    Buddy unless mars cap 3.499.30is not 80 its below 80which mean the radio is set to not transmit. 73

    • @loughkb
      @loughkb  6 лет назад

      Yeah, obviously. I was so focused on the menus at that point I didn't notice the freq.

  • @paulhastings3109
    @paulhastings3109 3 года назад

    That had to be adjusted carefully. So if FTDX-1200 gets crazy I know who to call
    Lol 73 gd dxing

  • @joelflam
    @joelflam 7 лет назад

    So knowing this why didn't Yaseu cover the costs?

    • @loughkb
      @loughkb  7 лет назад

      From what I've read, they did, during the warranty period. I didn't run across any 'official' yaesu announcement about it, but lots of forum and blog posts about it from techs.

  • @TheSlowpC
    @TheSlowpC 7 лет назад +1

    Got to do this to my 857 here ... Lost 2m/440 power sadly :(

  • @oxfd611
    @oxfd611 7 лет назад

    How much are those parts?

    • @loughkb
      @loughkb  7 лет назад

      About $33 each

  • @rafaelpaulino462
    @rafaelpaulino462 4 года назад

    How can i contac you,im in Tampa

    • @loughkb
      @loughkb  4 года назад

      My email is good on my QRZ page.

  • @yucliffecuffie2005
    @yucliffecuffie2005 2 года назад

    My radio has a probably not working good it a ft991a

  • @jeromegrzelak8236
    @jeromegrzelak8236 6 лет назад

    Did mine works now 1.2 amp works ok kg6mn

  • @jeromegrzelak8236
    @jeromegrzelak8236 6 лет назад +1

    Path yourself on your back kevin

  • @Japik79
    @Japik79 4 года назад

    I just burned my one... :(

  • @ERICtheLATE
    @ERICtheLATE 2 года назад

    3.499 mhz....no watts out....😎

  • @chucknelson1676
    @chucknelson1676 5 лет назад +1

    Thank you very much for this video. Recently one of the finals in my FT-991 failed, which I noticed when I failed to get into a local UHF repeater. This video helped a lot to assure me that doing the task wasn't too difficult. Fortunately I have access at work to a good quality de-solder station with suction and getting the part out wasn't too difficult though getting sufficient (but not too much!) heat on it to pull up the transistor wings once the solder was all removed was difficult I should have initially left a little more solder on the connection to help with getting heat to the pad. I chose to replace only the failed part and so far that has worked out well. I was able to balance the bias very closely between the old and new part. You are very correct about the adjustment being very touchy. It appears consensus on the correct working value is 950mA each and I was able to easily set that. The initial room temperature value on the one working device was 1.7A so if the failed one was similar this shows why it failed. Back to full power and getting good signal and audio reports so I think the surgery was successful. Thanks again! 73 NC7R

    • @loughkb
      @loughkb  5 лет назад

      Good to hear of your success. Glad to know my vid helped.