Kenwood TS-520SE

Discussion in 'Radio Circuits, Repair & Performance' started by AB0UA, Aug 30, 2012.

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  1. AB0UA

    AB0UA Ham Member QRZ Page

    I just bought a Kenwood TS520SE which needs some tender loving care.
    On first turn on of the main power switch, it ran for about 7 to 10 seconds
    and blow a 6 amp fuse. Opened up the case to look for any broken wires,
    touching wires to ground and general look over for the obvious. Any advice
    for locating or locations to look for or test. Will be down loading the manuals.

    Curt AB0UA
  2. W9GB

    W9GB Ham Member QRZ Page

    Curt --

    No possible way, we would know what you bought.

    Hundreds of these are appearing on market (SK estates, storage, pirate radio hacks)
    Just due to age (40 years old), many need maintence that had long ago been skipped.

    Did you buy this radio to operate on HF or to be a radio technician/repairman ??
    Last edited: Aug 30, 2012
  3. G4COE

    G4COE Ham Member QRZ Page

    You said you switched the 520 ON and it blew a fuse in a few seconds and was this was in the Rx mode?..... ought be easy to solve with a test meter, how about a shorted or leaky rectifier... or possibly a smoothing cap gone kaputt...... more so if it's not been powered up for ages - which 'could' be an important clue?

    Another clue is where you bought it from.... not from Ebay by any chance?

  4. KA5IPF

    KA5IPF Subscriber QRZ Page

    Easy, replace the 2 main filter caps. The big ones behind the VFO...
  5. AB0UA

    AB0UA Ham Member QRZ Page

    Just something to mess with during the winter.
  6. AB0UA

    AB0UA Ham Member QRZ Page

    I bought the radio at a flee market marked as CB base station for $75.00. I don't know how long it has been setting.
    Cosmetically its a 8 out of a 10. I down loaded the manuals to the radio and found in the trouble shooting guide of the
    service manual that it was either the AF unit or the HV supply. So I'm going to look there this weekend. I hope
    it will probably be the HV supply because I have some caps rated at 210 mfd at 450 volts. But if there is any other area
    that might be of concern from operators that have had this problem please let me know. My plans are to play with it
    for awhile and sell it.
  7. W5RKL

    W5RKL Ham Member QRZ Page

    When replacing capacitors, you should follow the 80/20 rule. The original capacitor values were 100ufd. Therefore, the maximum upper limit in capacitance should not exceed
    180ufd and the maximum lower capacitance value should not exceed 80ufd.

    I'm sure there may be more sources but the 2 that come to mind are


    Both sources sell suitable capacitors as replacements for the 520SE HV caps. I recommend you stick with the original "500VDC" voltage rating and do not exceed the
    80/20 rule.

    Mouser sells a snap in capacitor with the same 100ufd 500VDC value/voltage rating the original capacitors had.

    Mouser Electrolytic capacitors:

    Capacitance value = 100ufd
    Voltage rating = 500VDC
    Temperature rating = 105c
    P/N = 647-LGN2H101MELZ40
    Price = $3.42 (each)

    added information:

    You should also measure the diameter of the original capacitors. The HV caps in the 520SE are mounted using round clamps. The new capacitor should fit in the original clamp and the clamp,
    when tightened, hold the capacitor firm. The capacitor should not move within the clamp with the clamp is tightened. Use the "data sheet" link to determine the correct diameter (portion of
    the part number in the data sheet tells you what that diameter is).

    Last edited: Sep 1, 2012
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