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Thread: ten tec corsair 11

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  1. #1

    Default ten tec corsair 11

    Hi i have this ten tec corsair 11 hf rig that is in need of new transisor finals and i am looking for how to remove the old ones the right way before i try .

    The transistors are MRF458 and they are soldered in .

    Any help please !

    Thanks ,

    Steve VE3SMY

  2. #2

    Default

    It's actually a Corsair-II, not 11.

    I didn't look it up but these power transistors are almost always 4-tab devices, with one tab for the base, one for the collector, and two for the emitter and they're bolted in place with machine screws (usually Allen hex type) down to the heatsink immediately beneath them.

    Does that describe what you have?
    A government which robs Peter to pay Paul can always depend on the support of Paul.

    -- George Bernard Shaw

  3. #3
    Join Date
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    Default

    Steve,

    First off, contact Ten-Tec Service. They can provide some technical assistance, parts (not all parts are still in stock... it is a 25+ year old rig... and some can be obtained from other sources cheaper) and advice. I don't know if they still work on Corsair II's, to be honest, but I know they did up until fairly recently.

    Second, do you have the manual? If not, check the Ten Tec web site, under obsolete manuals. I think you can still download it -- for free.

    Third, try this great resource, the Ten Tec Wiki pages: http://tentecwiki.org/doku.php?id=home

    Fourth, check in to the Ten Tec email reflector, hosted on the contesting.com site. You'd be amazed at all of the help that you can get there.

    Good luck!
    WASHFest 2015, 28 Feb 2015, CSVFD Memorial Hall, SR 88, PGH PA

  4. #4
    Join Date
    May 2005
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    Remove two socket head screws per device. Unsolder four leads keeping track of which lead position is the one with the diagonal cut.

    You can buy replacement parts at:

    www.rfparts.com

    Remove the old thermal compound and place a very thin layer on the new devices. Bolt them in place and resolder the connections. Discard bad devices in hazardous waste collection. These devices contain BeO so use appropriate caution.

  5. #5

    Default

    I took a moment to look up the MRF458 and see it was offered two ways: With two machine screws and a flat base for mounting, or with a #10-32 stud for mounting.

    Either way, there's hardware involved. What's in the Corsair-II?
    A government which robs Peter to pay Paul can always depend on the support of Paul.

    -- George Bernard Shaw

  6. #6
    Join Date
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    3763 Lyle Avenue, North Pole, AK 99705
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    It's a good idea to use eutectic solder for these...AND an adequately sized soldering gun. You can do a LOT more damage to a transistor with an anemic soldering iron. You want to get things up to temperature FAST and then get out of there quicklyl!

    Eric
    "The more you know, the less you don't know."

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