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richajem
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Last Activity: 08-21-2019, 06:19 PM
Joined: 12-09-2013
Location: Montebello
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  • richajem
    started a topic Samsung - Plasma PN51F5500AF Wont Turn On
    in Troubleshooting TVs and Video Sources

    Samsung - Plasma PN51F5500AF Wont Turn On

    Hi forum --
    I can use some help with troubleshooting a Samsung Plasma - I tried to search the forum for like issues but they all vary from one set to another --
    Here is my TV issue; When the set is plugged in the red power light is illuminated ON. When I press the ON button the led flashes OFF and ON 3 times before it goes into a red double flash 5 times sequence. There are no other indicators as far as Picture or clicking. No Evidence of any bad Caps or Burn Markings - This TV is dead --
    I took some photos of the TV with the cover removed and I took some voltage measurements...
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    Last edited by richajem; 08-03-2019, 02:50 PM.
  • richajem
    replied to Need assistance -- Video Game CRT Color Monitor
    in Troubleshooting Computer Displays
    Re: Need assistance -- Video Game CRT Color Monitor

    Folks,
    Here are some pictures of the bottom board with my figures to the flyback pinouts along with other back side and top side pictures--
    Any support is appreciated.

    Thanks,
    Richard...
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  • richajem
    replied to Need assistance -- Video Game CRT Color Monitor
    in Troubleshooting Computer Displays
    Re: Need assistance -- Video Game CRT Color Monitor

    Another Update --- Any Assistance is appreciated --
    I did attempt to power up the board again after adjusting the B+ Voltage to 112V. I did place a 60W bulb as a load and swapped out the 60W to a 100W to be sure the load current difference would regulate the bus. And sure enough that delta was about 0.3V difference. I was impressed!
    Next I "placed" the Main switching HV Transistor and once again the High Voltage started up as I hear the static charge but shortly after the 2A Fuse cleared and this time the...
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    Last edited by richajem; 03-16-2018, 04:43 PM.

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  • richajem
    replied to Need assistance -- Video Game CRT Color Monitor
    in Troubleshooting Computer Displays
    Re: Need assistance -- Video Game CRT Color Monitor

    Here is an Update --
    After replacing Q902 with an equivalent, I noticed the voltage was still in the upper range of 161V +/-3V at which it tells me it still was not regulating.
    I visually checked the traces and noticed the silk screen on the bottom and top appear incorrect with the actual trace and reference to the schematic. The Base and Collector markings are reversed. After kludging the Q902 leads around to match the schematic and the traces, I powered up the Power Supply section only and the voltage was in the...
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  • richajem
    replied to Need assistance -- Video Game CRT Color Monitor
    in Troubleshooting Computer Displays
    Re: Need assistance -- Video Game CRT Color Monitor

    Hey Guys,
    I had to take an extended period of time away from troubleshooting this monitor to attend family matters -- I am here and i have some new discoveries -- Please read --
    So I went back to the forum to refresh myself --
    Hi RJ and stj -- I can still use your help!
    So I pulled out my meter and started to probe the power supply section (regulator transistors Q903/Q902/Q901) and found that Q901 was open - So after replacing Q901 with a comparable equivalent i powered up the chassis without the flyback...
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    Last edited by richajem; 02-24-2018, 11:26 AM.

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  • richajem
    replied to Need assistance -- Video Game CRT Color Monitor
    in Troubleshooting Computer Displays
    Re: Need assistance -- Video Game CRT Color Monitor

    Thanks RJ and Stj --
    That will be my weekend test -- Currently I have the flyback removed so I can test it easily. I will add a light bulb as a load.
    I uploaded a few photos of the top side and bottom side....
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  • richajem
    replied to Need assistance -- Video Game CRT Color Monitor
    in Troubleshooting Computer Displays
    Re: Need assistance -- Video Game CRT Color Monitor

    Hi RJ --
    I understand the Q903 wiring error on the schematic – I made that change according to your Post 5. Thank You again..
    What I was asking pertains to your brief description in post 5 in regards to the Flyback diagram and Pin assignments -
    You wrote -- They usually count all the pins, even the missing ones, on your flyback pins 11 and 9 (or 2 and 4 depending on how they number it) are not there but if counted you would get 12
    I just wanted to see if you can provide me with additional information...
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  • richajem
    replied to Need assistance -- Video Game CRT Color Monitor
    in Troubleshooting Computer Displays
    Re: Need assistance -- Video Game CRT Color Monitor

    RJ --
    Today I was studying the schematic especially the Power Stage Q903 and was scratching my head with how in the heck can the regulator operate with the 2 collectors going to no where. I am more familiar with series pass transistor circuits when the collector is ties to the unregulated side and the emitter is the output regulated side - I will study it more with the grounding of the collector.
    I am not quite following your flyback approach - Can you please elaborate a bit more?
    Also, How would you approach...
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    Last edited by richajem; 08-15-2017, 10:04 PM.

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  • richajem
    replied to Need assistance -- Video Game CRT Color Monitor
    in Troubleshooting Computer Displays
    Re: Need assistance -- Video Game CRT Color Monitor

    Hi RJ --
    I believe you are so very close to the actual schematic of the unit -- How did you know just by my description? Amazing -- thank you..
    What I noticed on the chassis is a marking with Model 700 -- Nothing more than that.
    The transistors I replaced were --
    Main Switching HV Transistor - Philips BU2520DF NPN Power Transistor SOT199 800V 10A
    Regulator Series Pass Transistor - 2SC5071 Silicon NPN High Speed, High Voltage
    Regarding the schematic I notice the flyback illustrates pin configuration...
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    Last edited by richajem; 08-14-2017, 11:35 PM.

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  • richajem
    started a topic Need assistance -- Video Game CRT Color Monitor
    in Troubleshooting Computer Displays

    Need assistance -- Video Game CRT Color Monitor

    Hi Forum,
    I can certainly use some help.
    I was kindly offered an upright arcade video game "Street Fighter" with a 19" color CRT monitor with a name brand "Yatta". I have reached out to many arcade parts houses and with the search in Google, I cannot find anyone that is familiar or have heard of this brand so I would like to reach out to all of you.
    First, I need to locate a set of schematics of the unit – Second I am in need to locate a Flyback Transformer BSC23-F1412A
    I started to troubleshoot the monitor and found that the 2A fuse was...
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  • richajem
    replied to Samsung-UN39FH5000FXZA-Will Not Turn ON
    in Troubleshooting TVs and Video Sources
    Re: Samsung-UN39FH5000FXZA-Will Not Turn ON

    UPDATE -

    I received the new Main board and it is installed -

    The problem is solved and the TV is up and running! Thanks Budm and Dick for your support with the troubleshooting efforts.

    Thanks-

    Richajem
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  • richajem
    replied to Samsung-UN39FH5000FXZA-Will Not Turn ON
    in Troubleshooting TVs and Video Sources
    Re: Samsung-UN39FH5000FXZA-Will Not Turn ON

    Budm,

    Check this bit of info out!
    As I was removing one of the mounting screws on the Main Board, it appears it was under mechanical preload. The board has a slight warp to it which can indicate after heat and Ambient cycles (ON/OFF) components could lose connection.
    I wanted to check under the sun for overall condition.

    I will reinstall it back and put a heat gun to it. Let me see if I get anything.

    But in meantime, i will look for a single Main Board on eBay. Yeah, I seen the board...
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    Last edited by richajem; 03-25-2016, 04:43 PM.

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  • richajem
    replied to Samsung-UN39FH5000FXZA-Will Not Turn ON
    in Troubleshooting TVs and Video Sources
    Re: Samsung-UN39FH5000FXZA-Will Not Turn ON

    Good Advise Dick!! Didn't need to cut and heat shrink the wire. Used a sharp Xacto blade and that did the trick.

    The result, as described by Budm-
    Back light came on but nothing else worked - So I assume the Main Board is still the culprit?


    Richajem
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    Last edited by richajem; 03-25-2016, 04:18 PM.

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  • richajem
    replied to Samsung-UN39FH5000FXZA-Will Not Turn ON
    in Troubleshooting TVs and Video Sources
    Re: Samsung-UN39FH5000FXZA-Will Not Turn ON

    Budm,

    Thank you, I do appreciate you helping me through these steps-

    I see your logic flow Budm.
    With the T-CON cable disconnected and the PS connected to the Main Board from the prior troubleshooting step, it appears all issues pointing to the Main Board.
    Do you recommend i do your last test step? I'm thinking I need to splice the wire to disable the BL_ON signal line to perform that test all to point to the Main Board. What do you think?

    Richajem
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  • richajem
    replied to Samsung-UN39FH5000FXZA-Will Not Turn ON
    in Troubleshooting TVs and Video Sources
    Re: Samsung-UN39FH5000FXZA-Will Not Turn ON

    Budm,

    I did tried your last test sequence and there is still no backlight with the T-CON cable removed and with the Main Board and PS cable connection.
    I would have thought it should not get the backlight ON when connecting from Main Board to PS Board since the initial issue lies in the Main Board.
    Is that a true statement?

    Richajem
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  • richajem
    replied to Samsung-UN39FH5000FXZA-Will Not Turn ON
    in Troubleshooting TVs and Video Sources
    Re: Samsung-UN39FH5000FXZA-Will Not Turn ON

    Hi Budm,
    And thank you for read and responding -
    Here are the pictures you requested and yes they are of the ones you provided from the link.
    In the normal configuration, as described in my troubleshooting steps, there is no backlight appearance.
    However, per your instructions, i did disconnect the cable from the main board to the PS board and YES, I have backlight!!
    So this does in fact point to a Main Board problem?

    Richajem...
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  • richajem
    started a topic Samsung-UN39FH5000FXZA-Will Not Turn ON
    in Troubleshooting TVs and Video Sources

    Samsung-UN39FH5000FXZA-Will Not Turn ON

    Hi forum,
    I can use some assistance with a TV that won't turn ON.
    When plugging in, the Power red LED is ON and that is the end of it.
    It will not respond to the Primary Switch located on the TV nor a remote function.
    I did some research before I posted here and so far majority of all problems have been pointing to the Main Board - But here is my troubleshooting outcome. What do you guys think?
    Main Board - BN94-06778C / BN97-07695D - 2 separate stickers Manuf/Vendor
    PS Board - BN44-00666A
    T-COM Board – V390HJ4-CE1
    I like to know if...
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  • richajem
    replied to Samsung LN52A850S LCD Vertical Line
    in Troubleshooting TVs and Video Sources
    Re: Samsung LN52A850S LCD Vertical Line

    I have the same exact TV and with the same sort of problems.
    1) Ghosting appearance even after replacing the T-Con board, still looking into panel tab bonds
    2) Single dead Line running right in the middle
    This tells you that these particular Samsungs had a manufacturer problem that Samsung didn't want to dive into as far as recalls or even remotely to help.
    So far I took it apart as far as the panel but not as deep into the removal of the panel frame to see if the tab bonds are the issue. That is next.
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  • richajem
    replied to New Members - please post your introductions here
    in Announcements & Related News
    Re: New Members - please post your introductions here

    Topcat, nice forum you put together.

    Hey Guys and Gals,
    My name is Richard, I am from Los Angeles, Calif I am an EE in the field of power Electronics. My field of expertise in designing switch mode power Supplies but I like to work on Electronics period. TV's, Power Amplifiers (Cars and Home), Model Trains, Video Games, and now on HDTV's. Yippy!!
    I am looking forward to sharing and learning here with you all.
    See more | Go to post

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