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Repair Tuner or Buy New

Discussion in 'Ham Radio Discussions' started by N3WVB, Aug 8, 2017.

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  1. WA3QGD

    WA3QGD Ham Member QRZ Page

    there are those who swear by them,and those that swear at them,when one learns that impedance's are better matched above 100 ohms and that sufficient voltages and currents are present to punch through dielectric with antennaes too low too short or too close to conductive objects,you may be able to match some frequencies at 50 to 100 kc's on a coax fed dipole,after that you will need to go open wire line and 1 to 1 1/2 wavelengths in the clear to multiband 80 thru 10,loading any of the compromise antennaes will produce mixed results,You may look at why KW Match boxes are in big aluminum cabinets,not a thing wrong with the mfj stuff,just dont follow their tune up guide and start blind with a 100 watts,do it with 5 watts and as you refine your match increase power until you need to touch things up slightly, good luck.
  2. KA9JLM

    KA9JLM Ham Member QRZ Page

    To not repair, Is to break the golden ham rule.
    WZ7U and K3MCA like this.
  3. K1MMI

    K1MMI Ham Member QRZ Page

    The current model MFJ-989D sells for $325 at Ham Radio Outlet. You have gotten over 10 years of use from your MFJ-989C. A very good and reliable tuner.

    I'd suggest going to the MFJ website and going to the Customer Support area and fill out a job ticket with a description of your problem. They can give you suggestions on what may be the solution to your problem. They can also give you a pretty good estimate of the typical repair charges for the MFJ-989C. It would not surprise me if the total cost for repair parts, labor and shipping both ways is in the $100 to $150 range. If the repair is under $150 then it seems to make sense to repair it.

    Most Hams I know don't have a technical background and don't feel skilled enough to troubleshoot something relatively simple as a mechanical tuner. Based on your skill level and suggestions from MFJ to repair your tuner, it could end up being a pretty simple and cheap repair for you to do. Keep in mind MFJ does charge at least $12 to ship any parts to you.
    N3WVB likes this.
  4. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I don't own one of these (never did) but the scuttlebutt for years has been they rarely fail except for the drive system for the mechanical dial turns counter (purely mechanical fix), the roller inductor (occasionally needs replacement) and the sensing diodes in the SWR meter circuit (electrical repair, but pretty simple).

    I'd think if there were bad solder joints "from the factory" (a common "MFJ" issue on various products) that would have shown up years ago, and not caused a sudden failure.

    Like many MFJ products, very solid design. The only "issues" are workmanship related (like someone missing a solder joint) and hams usually just fix those themselves.
  5. KA9JLM

    KA9JLM Ham Member QRZ Page

    If you do not have the ability to repair it yourself, There are normally hams near you that would be glad to help.

    2 meters and 70cm is a good place to meet local hams.

    I have NEVER heard anyone ask for help that did not get it.

    Maybe that is a Texas thing, Where we like to help others.
  6. N5PAR

    N5PAR Ham Member QRZ Page

    I had an MFJ 921 that came with the Swan SX700 I bought for $60.00 years ago. It was my first HF rig. I was in the leaning phase of tuning the thing and let the smoke out of the tuner. I found a schematic for the tuner found the burnt resistor. Which wasn't too difficult to spot since it was burnt. Found the value on the schematic. Bought a new resistor at Radio Shack soldered it in and fixed it. I gave it to a new amateur about a year ago it's is still working.
  7. K4PIH

    K4PIH Ham Member QRZ Page

    My address good here on the ZED.
  8. WE4E

    WE4E Ham Member QRZ Page

    And usually good advice.
    N2SUB likes this.
  9. W3WN

    W3WN Ham Member QRZ Page

    If you decide to buy new, I'll give you $40 plus $15 for shipping for it.
  10. KE8EZZ

    KE8EZZ Ham Member QRZ Page

    I repaired my MFJ tuner, and I'm a relative newbie to the world of radio tech. Look at the circuit diagram in the manual... It's really very simple.

    All mine needed was a new meter panel, and the previous owner decided to mess with the pots to try to calibrate it, so I had to play with those a little to get it accurate.

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