Trouble with Mirage D1010 Amplifier

Discussion in 'Amateur Radio Amplifiers' started by K5BZI, Jul 31, 2020.

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  1. K5BZI

    K5BZI Ham Member QRZ Page

    Hi.

    I have a Mirage 1010D. when connected to my Astron RS-20A, as soon as I turn the power supply on, (amp off) the fuse blows in the power supply. This power supply works fine when connected to my Mirage B1016 2M amp.

    I am handy with electronics, and can follow a schematic well enough to keep my 80's Yaesu radios working, but have no experience working on these amplifiers.

    Could someone give me some pointers on what to look for, where to start, etc.

    Thanks in advance.

    -Ray.
    K5BZI
     
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Did it work fine for you before this?
     
  3. K5BZI

    K5BZI Ham Member QRZ Page

    I bought it non-working for cheap.
     
  4. KM3F

    KM3F Ham Member QRZ Page

    Aside from a fault, the 1010 takes a big gulp of current at power up because it's charging a high value of capacitance for the bias circuit. The bias circuit is a Zener and big power resistor load to try keeping the bias stable under drive conditions.
    I have one and it acts that way unless I use a larger capacity power supply.
    A 20 amp supply is not large enough for that amplifier.
    It's circuitry is not the same as the 2m units.
     
  5. K5BZI

    K5BZI Ham Member QRZ Page

    Thanks KM3F! Maybe that is my only problem. Guess I'm in the market for a PS. Any recommendations?

    -Ray.
     
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Before springing for a new power supply I'd do some troubleshooting.

    Sounds to me like you have a short circuit on the power bus. The +DC supply line (and ground, of course, which is -DC) are connected to the PA transistors and the high current doesn't go through the panel switch. If "someone" used the amp on FM with transmissions longer than a couple of minutes at a time, it was pretty common for the transistors to overheat and fail, which can result in a nearly short-circuit across the bus.

    Some used those amps on ATV which is very stressful even at 30W carrier power.

    I'd make some measurements first. A new supply won't fix shorted transistors.:)
     
    K4AGO likes this.
  7. K5BZI

    K5BZI Ham Member QRZ Page

    Thanks!

    I checked, and there is continuity between the point where the positive power terminal connects, and the point where the negative cable connect. There are two boards in this unit connected at three points by jumpers wires. I’m thinking i’ll break these connections so to isolate the boards and see which one has the short.

    Also, before I do that, I have a friend who has a 35 watt PS I could test on. I tested continuity on my 2M Mirage amp and there was continuity between those points albeit not nearly as high a value.

    -Ray.
     
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I think you meant "not nearly as low a value" (of resistance) but meant the same thing.

    Yes, they'll all show some continuity, that's normal -- but it shouldn't be "0 Ohms" or anything close to that.

    What is the resistance reading (in Ohms) that you're getting with the D1010?
     
  9. AI3V

    AI3V Ham Member QRZ Page

    This is wrong.

    A rs-20 will run a d1010 just fine.

    Rege
     
  10. AI3V

    AI3V Ham Member QRZ Page

    95% chance either the final transistors or the reverse polarity diode are ruined.

    Figure $100 for finals,
    $1 for the diode.

    Hope you get lucky.

    Rege
     

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