Kenwood TS530s LSB issue

Discussion in 'Radio Circuits, Repair & Performance' started by KM4YTW, Oct 3, 2019.

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  1. KM4YTW

    KM4YTW Ham Member QRZ Page

    I picked up another 530 today and it has a lsb issue. Long story short , i can get LSB to work if i tap the crystal on the pll board. If i just push on it, it doesnt do anything. If i tap the crystal it starts working. Once its working if i turn the radio to usb and back to lsb it will not work till i tap on it. It also works if i turn the if shift fully counter clockwise. Anyone had this issus ? Im thinking maybe its the lsb crystal.
     
  2. K7TRF

    K7TRF Premium Subscriber QRZ Page

    It might very well be the LSB crystal but on a Kenwood of that vintage I'd start by touching up the solder joints in and around that crystal. Sometimes adding a small value capacitor across the crystal can also bring a tired crystal back to life, something in the 2 to 5 pf range is often all it takes. You still may end up replacing the crystal but it's easy enough to try a few simple fixes like reflowing solder joints or tacking a small cap across the crystal first.
     
  3. KM4YTW

    KM4YTW Ham Member QRZ Page

    Thanks David, ill try the cap trick , maybe that will kick it off. Nice shack you have there. !
     
  4. KA9JLM

    KA9JLM Ham Member QRZ Page

    You may want to clean the band switch if you have not done so.

    It can cause strange problems if the contacts are not making good connection.
     
  5. KM4YTW

    KM4YTW Ham Member QRZ Page

    Thanks Don, yeah I'm gonna go thru it and get everything cleaned up that can be cleaned. your right Kenwood band switches often give trouble espically if it's been well.used . Thanks
     
  6. KM4YTW

    KM4YTW Ham Member QRZ Page

    Ok, i got everythkng cleaned and still the same thing. I need a 8.8315 MHZ. Crystal . Does anyone know where i can source one?
    Thank you.
     
  7. K7TRF

    K7TRF Premium Subscriber QRZ Page

    You might be able to find one on the used market if you're patient but that could take a while.

    These guys keep ham rig crystal specs and have no problem selling single crystals. They should have no problem filling that order: http://www.quartslab.com/
     
  8. WR2E

    WR2E Ham Member QRZ Page

    Did you look for cracked solder connections?

    Did you try the couple picofarad cap across the crystal?
     
  9. KM4YTW

    KM4YTW Ham Member QRZ Page

    Yes i tried to 4pf cap, cleaned everything reflow the solder joints. Still the samt thing.i can tap the board all day long and it does nothing. But if i tap the back of the LSB crystal it works. So im betting its the crystal.
    I found a board on ebay but its just too high to get that one crystal. Ill check that site.
    Thanks
     
    WR2E likes this.
  10. SM0AOM

    SM0AOM Ham Member QRZ Page

    There is a clue in the description that points in the direction of an LSB crystal with reduced Q due to age or contamination, that it works with the IF Shift control in the CCW end position.

    A way around this is to increase the feedback in the oscillator circuit around Q41. The capacitor C168 could be decreased from 100 pF to 82.

    Another way is to increase the gain of Q41 by reducing the emitter resistor R138 somewhat, or fitting a "hotter" transistor in place of the 2SC1675 with higher current gain and transition frequency. I would use the BF199 or similar.

    73/
    Karl-Arne
    SM0AOM
     
    K7TRF and WR2E like this.

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