X-108 Info X-108 won't transmit

Discussion in 'X-108 TRX' started by Scott Fraser, Mar 27, 2018.

  1. Scott Fraser
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    Scott Fraser KN6F X-108 Member

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    After successfully using the X108 for FT8 on 40M and 15M the past two months, it has decided to stop transmitting.
    • No transmit on any mode or any band
    • S-meter will go to max after a few minutes. If the PTT is pressed, the S-meter will clear and go back to normal operation, then back to 60 over 9 in a minute
    • Still receiving signals and able to successfully decode
    • On Receive in AM mode, large amount of static like crinkling cellophane even when connected to dummy load.
    I'll be diving into it next week but thought I'd ask to see if these symptoms sound familiar to anyone.
    Any ideas?
    Is there a service depot for these rigs?
    Thanks
    Scott, KN6F
     
  2. Chuck
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    Chuck Chef-Boarder X-108 Member

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    Hi Scott, well today is the second time my rig has stopped transmitting, first time for about two days, then started working as normal. and now again. Emailed the guy I bought from on ebay for warranty service info and so all he said was " How about your X108G now?
    the max power should be 18W,
    and I advise you join into X108G facebook group,
    you will get more support there."
    Not much confidence in that so far, any way in same boat as you and if I hear, learn will post here and hope one of us can figure this out.. or may look for a new rig!!!
    73
    chuck
     
  3. Scott Fraser
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    Scott Fraser KN6F X-108 Member

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    Chuck, yep, looks like same boat. I have some feelers out in China and if I hear anything I'll let you know. I'm hoping their 2 year warranty applies to this unit as I purchased in in Sep 2016. I'm already looking at new rigs.
    73 Scott
     
  4. Scott Fraser
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    Scott Fraser KN6F X-108 Member

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    I haven't heard back from China and went ahead and bit the bullet and opened up the rig. Sure signs of overheating with the digital mode as the silicone grease had started to migrate around the bottom.

    I found the 16W output mosfets at hobbypcb and ordered them today. ($20 for four) They are through hole packages, so I will need to trim and form the leads for the TO-220 surface mount pads.

    I then removed the shielding from the transmit section and removed the two fets (RD16HHF1). There are a total of three in there, one driver and two outputs. I went on the premise that the driver is only working at a small percentage of its rated power so focused on the two outputs.

    I pulled them both out and sure enough, one fet failed with a drain to source short. Typical failure mode for fets.

    So now I get to wait for the replacement fets to arrive next week and hopefully will be back on the air shortly thereafter.

    Here are the parts I ordered.
    Amateur Radio : RD16HHF1 Transistor - 4 Pack

    When I put it back together, I will most likely mount a muffin fan on the bottom of the rig to keep the heatsink a bit cooler. Small cooling fins and being on the bottom without airflow convection doesn't do a great job at cooling. I did have it raised up off the desk, but that obviously didn't help much.

    KN6F
     
  5. Chuck
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    Chuck Chef-Boarder X-108 Member

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    Scott. Make sure the driver is not a RD06HHF1, notice the o in front of the 6, I also have no contact form seller or factory and a friend is looking into mine as I type this ,,, what he has found so far is no rf from main board ?? Keep me up with how it goes and good luck

    73
    chuck
     
  6. Chuck
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    Chuck Chef-Boarder X-108 Member

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    Trying to identify this part AD 831APZ #0618 886238.1 - looks like a 20 pin device - traced RF up to this device but not out. For whatever reason did get output for a brief moment then nothing..Thanks for any help identifyng this device...

    73
    chuck
     
  7. Chuck
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    Chuck Chef-Boarder X-108 Member

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    OK, found it already, PLCC on ebay around $ 9.00.

    Chuck
     
  8. Scott Fraser
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    Scott Fraser KN6F X-108 Member

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    I got the parts. Spend a bit of time getting them soldered in place. The extreme heat sinking and close quarters of the traces makes it pretty difficult. First tests, still zero output. I have to come back to it later and start probing and testing. The stacking of the boards certainly doesn't make testing any easier.
    Scott
     

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  9. Scott Fraser
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    Scott Fraser KN6F X-108 Member

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  10. Chuck
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    Chuck Chef-Boarder X-108 Member

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    Not able to identify a number of components as one schematic has numbers but missing part as found on board(s) and others show component with no number. Going to factory for repairs -

    73
    chuck
     
  11. Chuck
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    Chuck Chef-Boarder X-108 Member

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    Heads Up!

    My radio is three months old... shipping to factory for repair 70.00 and that does not include repair and parts fee. Yep I made a mistake and realized after shipping,,, I had bought my X108g from a ebay seller that was not a Xiegu authorized seller. It is in their warranty statement..so no warranty. The ebay seller just said to join facebook group for support. Just to let you know be careful where you buy a new radio etc.
     

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