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HOT slowly overheating

Discussion in 'Electronic Repair' started by Ken G., Dec 27, 2006.

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  1. Ken G.

    Ken G. Guest

    I`m working on a 9`` Orion tv dvd combo 2003 model , same set as the
    Toshibas for those familiar with these .
    It uses a samsung chassis with a small size package HOT .
    Ths set had HOT shorted and the board under the HOT was browned from
    heat .
    I replaced the HOT with a good original part from a smashed tv set .
    This set now works just fine but after around an hour the HOT tiny heat
    sink gets to hot to keep a finger on .

    I have ESR tested capacitors in the osc circuit and swapped out the osc
    coil but still gets hot . I am suspecting the flyback ??
    Comments ?
     
  2. Meat Plow

    Meat Plow Guest

    Take the flyback from the smashed set and swap.
     
  3. Guest

    If everything else seems ok, ie, picture and deflection are ok, can you
    increase the heat sink size somehow? Maybe a bad design from the
    beginning.

    H. R.(Bob) Hofmann
     
  4. boardjunkie

    boardjunkie Guest

    Either the heat sink is way undersized or the retrace tuning cap may be
    leaky. Sounds like more HS surface area is a good idea either way.
     
  5. what did I tell you otterfucker? Orion does make crappy tvs for Toshiba.
     
  6. A bad design? No shit asshole.
     
  7. Ken G. wrote:

    of course it's going to get hot. It's a HEAT SINK. What part of that
    don't you understand, you dumb motherfucker?
     
  8. Ken G.

    Ken G. Guest

    I have worked on several of the Toshiba with the same exact heat sink
    and HOT and chassis and never found one till now that got hot like this

    The picture shows no sign of any problems .

    My next step was to put in the flyback from the smashed set ... THANKS
    .. Today i also found another 02. 9`` set that had a shorted picture
    tube only it had a vcr in it but same exact HOT . Fylback # ??

    I thought of adding more heat sink but thats not always the best thing
    to do .
     
  9. Ken G.

    Ken G. Guest

    of course it's going to get hot. It's a HEAT SINK. What part of that
    don't you understand,

    I love you and i want more !
     
  10. Guest

    Let us know what finally happens. (about the tv that is )

    H. R. Hofman
     
  11. I had some similar problems with other TV brands.
    Regularly the HOT was not driven properly.
    In one case the electrolytic capacitor to the base had lost capacity,
    in an other case a solenoid parallel to a resistor to the base was
    not soldered correctly on one end.
    The HOT can survive only if it really works as a switch, ie, strong
    input signal and short pulse rise times.
    Good luck,
    H.
     
  12. b

    b Guest

    Ken G. ha escrito:
    did you just esr the caps in the hor drive cct or actually change them?

    -B.
     
  13. A properly designed and functioning HOT should not get hot.

    Either a problem with the drive or the output circuit can result
    in excessive dissipation in the HOT.

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     
  14. b

    b Guest

    Sam Goldwasser ha escrito:
    You haven't worked on many Samsungs , have you! ;-) they're so mean
    with the metal, piddling little heatsinks mean the trannys always seem
    to run hot but somehow they work.
    also some of the the newer sharps and daewoos don't even heat sink the
    HOT :-o

    -ben
     
  15. or maybe he just changing the channels too fast.
     
  16. Right. Note the part about "properly designed". :)

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     
  17. Looks to me like you need a ring tester for flyback (LOPT)
    transformers. Dick Smith makes one that we, and others, sell - if DS
    EVER makes any more that is (backordered for a month or two so far!).
    Still a ring tester is great, and is a useful tool on the TV/Monitor
    repair bench. You can pick up second hand ones on eBay - Sencore and
    the like.

    We test all our monitors with a ring tester (Bob Parkers design - Dick
    Smith sells) before we recap them - saves a lot of trouble.

    John :-#)#
    --
    (Please post followups or tech enquires to the newsgroup) John's
    Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 Call
    (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
    www.flippers.com "Old pinballers never die, they
    just flip out."
     
  18. Franc Zabkar

    Franc Zabkar Guest

    I'd look for an electrolytic cap on the primary side of the horizontal
    drive transformer.

    - Franc Zabkar
     
  19. Ken G.

    Ken G. Guest

    Ok i finally got back to this thread . I only ESR the caps , i didnt
    change any . I did however take the flyback off the newly found set and
    put it in the overheating set and the overheating stopped . I left the
    set on all night long and in the morning the HOT heat sink was only
    slightly warm .

    I know these tv sets are cheaply made and all but this whole project was
    free accept my time and this is what people buy and want fixed so fix i
    will .
    The little set has a DVD in it and a 12 volt jack and still looks like
    new . Someone will like it .

    Thanks for all the pointers and technical info .
     
  20. Franc Zabkar

    Franc Zabkar Guest

    Why Do Apparently Similar or Better HOTs Sometimes Run Hot:
    http://www.repairfaq.org/sam/deflfaq.htm#dsasb

    Typical HOT Dissipation:
    http://www.repairfaq.org/sam/deflfaq.htm#dsthd

    Here is an excerpt from the aforementioned URL:

    ===============================================================
    Here are some measured values for TV HOTs with optimized drive:
    (From: David, a Philips application engineer).

    14-21", 16 kHz: About 1 W (some have the HOT running in free-air)
    21-36", 16 kHz: Less than 2 W (some new large CRT's only need 9 A
    p-p)
    25-36", 32 kHz: Less than 4 W (dissipation really is prop. to
    frequency)
    ===============================================================

    - Franc Zabkar
     
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