Youkits HB-1B MK3 issues

Discussion in 'QRP Corner' started by WM7WM, Sep 16, 2018.

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  1. WM7WM

    WM7WM Premium Subscriber QRZ Page

    Hello all:

    I have a new 2018 HB-1B MK3 transceiver with factory issues and wonder is I’m not alone.

    First issue, which Yimin suggested a fix, is a barely audible Morse notifications that play when you hold down CQ/SET key. The fix is a 4.7K resister soldered on the circuit board. I wish he suggested I send the unit back for a replacement that has the fix but, alas, the Chinese radio downfall. Has anyone had to fix theirs? Does the fix work? I’ll try this coming week and report back. (The photo of the repair/mod is posted in my eBay review)

    Secondly, the CW pitch is way, and I mean way to high. Almost 3600 hz vs the 700 advertised and well above the 600 hz I prefer. The manual states rotate VC1 to adjust the cw pitch. In my unit, there is zero effect on the CW pitch turning VC1 in any direction. Has anyone had a similar problem or experience?

    Otherwise, this is a great travel rig that really is a pleasure to own and operate. I really need the above problems fixed though to really have what I thought I was paying for. If fixed, the value at $299 (I paid $270) is outstanding.

    73

    Wes/WM7WM
     
    KL7KN likes this.
  2. KL7KN

    KL7KN Ham Member QRZ Page

    Given that the MFJ-9200 is the HS-1A - derived from the HB-1A //and the HS-1B is now sold as the HB-1B(2018)

    [​IMG]
    HS-1B 2 (see lower RH corner) This image is for you to compare to your YHB-1B main board

    The above is because I don't have access to an image of the HB-1B(2018) w/o the relay stack daughter board pulled - but, I believe you will fin d the HS-1B and HB-1B(2018) have the same mother board.

    My point - I don't believe the VC will change the CW sidetone (on TX) because VC is used to adjust the BFO xtal frequency - this to 'center' the incoming signal in the crystal ladder filter pass-band.

    The keyer chip (IC7) generates sidetone out of PIN 7 of the chip. This looks to be the same setup as in the -9200 You also indicate barely audible CW annunciation, which further leads me to believe the keyer chip iis the cause of your issue

    The chip is the same, the designer is the same, mfj is the same as used for the 9200 - hence, this most likely the same setup for your HB-1B(2018). BTW - the keyer chip is the same across the entire HS//HB series. tHIS CHIP is also used the CR kits cr-10X QRP RADIOS.

    upload_2018-9-17_10-39-57.png
    as you can see, there is no VC as part of the circuit.


    upload_2018-9-17_10-44-18.png

    here is the BFO (on the -9200) and VC (marked as CV) - so there you are.

    BTW - the schematic was drawn by Steve, KD1JV - thanks again to hom for his work on this.

    This does fix the high pitched sidetone issue - but I believe it explains why adjusting the VC will not provide a fix.

    And now you should go back and check how the signal is applied tot he ladder filer as it is not likely out of adjustment.

    See my manual for the adjustment procedure - http://www.ok1in.cz/userfiles/downloads/08_25_`17_MFJ9200_Troubleshooting_guide.pdf

    (yes, this guy posted my copyrighted material w/o permission) So, use his bandwidth.

    Fianlly, I could be completely wrong, but the Vendor has no English language technical material or even a schematic available, I can only guess based on the above description

    Hope this helps.
     
    Last edited: Sep 17, 2018
    W4CDO likes this.
  3. KL7KN

    KL7KN Ham Member QRZ Page

    Also - Wes, you were kind enough to post pics of your DCW-1 - how about some pics of the HB-1B board with and without the relay deck and SWR sensor?

    thx
     
  4. WM7WM

    WM7WM Premium Subscriber QRZ Page

    Ugh.

    Thanks for the research and education.

    Sure, I will post photos as able. I’m flying tomorrow and waiting for the 4.7k resister for the fix Yimin suggested. I’ll report on both and post photos.

    BTW, I’m going to sell both DC-1’s dirt cheap. One works completely, the other, mostly. The second one has the tuner card but it doesn’t work. They were fun to play with but now time to move on. I’ll post on eBay soon.

    Thanks,

    Wes/WM7WM
     
  5. WM7WM

    WM7WM Premium Subscriber QRZ Page

    As promised, a few photos of the inside including one of the Mod for audio menu weakness. I'm happy to report that the Mod worked very well and the Morse Audio Menu Notifications are loud and clear. I considered throwing my Heathkit resister substitution box across the fixes ( in lieu of a variable resister to test for the best result), but, alas, I was nervous even putting heat to an SMD of a new radio from China as I'd be on my own if anything went wrong. Speaking of China, Yimin and Shawn are MIA on these threads, emails, inquiries, etc. Zero support from Youkits. I have had mild success in the past. Maybe they want MFJ to takeover but they haven't chimed in either. Oh, well. Buyer beware. Still, the HB-1B is in fine order and look forward to getting on the air. There is a Youkits Yahoo group that I think I'm the only contributor. moving on, now.

    73 all.

    Wes/WM7WM

    PS DCW-1's both sold.
     

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  6. OH7XM

    OH7XM XML Subscriber QRZ Page

    Wes
    Do you have scematic for HB-1B?
    Have got to repair one where rx/tx doesnt work, and pin 5 stays high all time,, believe that keyer ic is broken, and dont know, where find that PIC (programmed one:) )
    Arno OH7XM
     
  7. KB4MNG

    KB4MNG Ham Member QRZ Page

    I had a very bad experience with a you kits radio just out of warranty. Worked great except the keyer went south. Seems like it was a mcu(?) known problem. The guy that frequents the forums said he would look for the part but never got back with me on it. I was offered a new one at half price, which was pretty good but I moved on....
     

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