Yaesu 857d Zebra Stripe Problem Fixed?

Discussion in 'Ham Radio Discussions' started by AJ2I, Oct 4, 2019.

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  1. AA7EJ

    AA7EJ Ham Member QRZ Page

    OK, I shall engage in a discussion.
    I made few attempts to obtain faulty control head from operators who where replacing it and had no use for the faulty one.
    Obviously I was not successful.
    It would be nice to have an actual detailed picture of the LCD to PCB hardware, just to have some base for speculating what could be wrong.
    Of course my first speculation is - this is NOT LCD substrate problem - it is a mechanical / connection of the LCD to PCB.
    But I could be wrong.
    However, when LCD was first introduced as a ( mass produced and used ) display component it was known that the substrate MECHANICAL / pressure connections WERE / ARE an issue. There is no soldering, to my knowledge, just a pressure connection carrying minuscule current.

    As far as rig's fans goes - the control head has NO indirect or direct way to benefit from the running fans.
    It would probably make things even worse.
    Again speculation.

    It woudl benefit the community if some users of REMOTE control head chimed in with their experience.


    Back to "vendor's issue" - if they were really interested in resolving this OUT of warranty (!) issue, they could provide detailed instruction / pictures / procedures how to fix it . Enough said.

    So - my original offer still stands - I'll buy your stripped , discarded FT 857 control head, and will attempt to REAL fix it.

    73 Shirley
     
    SA6CKE likes this.
  2. VK4XJB

    VK4XJB Ham Member QRZ Page

    My control head is still needed to run the radio. A very rough summary and a link to a couple of pics from a local forum.

    This is a post someone made on an Australian forum with 2 pictures of the pcb + ribbon + lcd. It shows the black blob in the middle of the ribbon. The 2 theories I know of are temperature and humidity make what is holding the ribbon in place to fail and bad joints with the chip in the middle of the ribbon.

    I have measured the temperature of the case and lcd. On mine the lcd stays with in 1 to 2c of the case. At the moment 27c in this room. The radio case is 37c and the lcd 35c. The temperature of the head unit follows the temperature of the radio. If I force the fans on the radio will cool and the lcd slowly follows. The radio seems to settle 10c above ambient. In summer room temp varies from around 20c to 38c and in winter about 10c to just over 30c. The humidity gets reported anywhere from 7% to 100%. The high humidity days the fog is think enough can not see any neighbours. The other never mobile 857d has had similar temperature and humidity.

    What I have seen with mine the number of dead lines changes as the temperature changes. The number of dead lines change as the ribbon is moved. That tells me there is intermittent joint but I never isolated it to the either end of the ribbon or the chip in the middle. The other person thought he had isolated his to 1 end of the ribbon and added some packing to apply pressure. Every time he tried that any good results were only temporary.

    At the moment mine only has 13 lines dead which is unusual. It can get bad enough I lose the mode, part of the s meter, part of the voltage reading and 2 of the frequency digits. When it gets worse I use cat control to know what mode and frequency it is set to. Tonight is the 1st time in a few years I can remember it cleanly showing 13.8V. The vertical line in the middle of the 8 was the 1st to go but is back tonight.

    Something came up last night so only hitting post reply the following morning. The radio is currently 23c instead of last nights 37c and a lot more lines have gone with the radio cooled down. If you do have ideas that do not involved spending over 1/4 the price of a new 857d I can think of a few people that would be interested.
     
  3. KD0CAC

    KD0CAC Ham Member QRZ Page

    How about a link ?
     
  4. VK4XJB

    VK4XJB Ham Member QRZ Page

  5. KD0CAC

    KD0CAC Ham Member QRZ Page

    Thanks
    I worked on some products that there was just the LCD laying on top of connector , and over time there was shrinkage / what ever and made little to no contact , I cut thin cardboard spacers that acted like a window - let readings to be read , and then put added pressure on LCD to contacts , worked good .
    Obviously not the same with the 857 , but many time we can find a way ;)
     
  6. AA7EJ

    AA7EJ Ham Member QRZ Page

    Most LCD input (multiplexed , common ) connection to processor then there is as an actual LCD controller - usually unlabeled black "blob".
    From the controller "blob" there should be multitude of "traces" to the LCD substrate,
    From posted pictures - it looks as there is a ribbon edge connector at the end of the ribbon cable.
    If it is indeed an edge connector - it should be removable.
    That woudl be the ONLY mechanical / friction connection in the setup and possible source of the problem.
    We are talking about multitude of connections - these are in no longer simple multiplexed signals, but we know the problem affect the VERTICAL enabling "trace(s) ".

    The LCD is essentially x * y matrix of dots.

    Perhaps actual LCD part #, NOT the # of the control head , from Yaesu woudl also help.
    That could narrow the problem area down.

    Keep in mind that control head has is own (micro) processor and is powered with +8V from main PCB.
     
  7. VK4XJB

    VK4XJB Ham Member QRZ Page

    There is no edge connector that can be taken apart and put back together. Just took my control head apart and the ribbon is connected to the pcb as per the photo in the link I pasted. That photo shows the ribbon connected to the pcb.
     
  8. AA7EJ

    AA7EJ Ham Member QRZ Page

    OK,
    cannot argue with what you are observing, but that makes no sense.

    The ribbon has to have TWO ends , one appears to be soldered to the PCB and the other somehow connected to the glass LCD substrate.

    In theory LCD glass end SHOULD not have a solder connection on it.

    There exists a detailed shop manual and I will be searching for it , maybe it will help.
    But I do not recall many mechanical details in it , including the control head.
     
  9. AA7EJ

    AA7EJ Ham Member QRZ Page

  10. WA6MHZ

    WA6MHZ Subscriber QRZ Page

    I bought a 857D hoping to replace the war surplus ICOM 706 in my car. But after discovering the Zebra Stripes issue the radio was put in a go kit. Stripes still emerged. Not too bad, but annoying. Not worth it to spend several Hundred bucks for a replacement module. I will just hafta LIVE with it! Too bad too! The 857D is a really nice rig! But that flaw nixes making it usable. We oughta get a CLASS ACTION SUIT Against Yaesu for this one! LAWYERS??
     

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