Monitor: Sony SDM-HS74P LCD

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  • forswitch38
    Member
    • Sep 2015
    • 10
    • USA

    #1

    Monitor: Sony SDM-HS74P LCD

    Before I explain the monitor, I want to say I'm new here. I also am a hardware noob. I've spent most of my life with computers. I've built one and I've programmed software. But I've never soldered on the circuit board or even hacked a graphics card to put a custom heatsink on it. See, at the hardware level, the most I've done is simply oiled some fans.

    Now onto the problem...

    This one came with a prebuilt computer in 2005. I think in 2010 or 2011 it started shutting off. I was able to keep it working by pressing menu buttons and changing the brightness--if I recall rightly. There was only a couple seconds when this would work, after which it would stay off. However, at some juncture, that stopped working. So probably in 2010 or 2011 I put this thing in storage and forgot about it. Now I picked it up again because I want to try and get it working again.

    Just to clarify, what happens is this:
    1) I turn it on
    2) Takes a few moments and then the screen lights up and shows whatever is on it. If the cord isn't connected, it'll say there's no signal. Otherwise, it'll act normally and show whatever is supposd to be onscreen.
    3) About 2 seconds later and it shuts off

    I've done hte flash light test and I know things are still showing on the screen. For example, I can see the bootup screen prompting me for my password. If it's in Widnows, I see whatever should be there. So I'm led to believe the inverter or CCFL's or wiring inbetween them is failing, meaning things ARE on screen, but not lit up.

    This--I believe--is the service manual:
    http://www.go-gddq.com/upload/2009_0...0810482821.pdf

    From what I can tell, it's a heavy construction, not lightweight. I removed the cover via screws, so I didn't have to monkey with any tabs, as I feared.

    Here's a picture of its layout:


    I lack the knowledge to make much sense of it. However, I'm guessing the power board is in the middle, the inverter board on the left and the processing board on the right.

    After I opened it up, I looked at the capacitors to see if any were bulging. Unfortunately, there was not any obvious bulging, as I had hoped there would be. There is a capacitor on the right which is crooked, but it doesn't look like there's any bulging underneath or above. (Ignore the fact it's discolored on the image above--that's my shadow) All of the capacitors looked, but except there were 2 which caught my interest. These:

    (Note the crack on the right one and the copper colored discoloration on the left)



    Disregard the green goo inbetween them. That was in other places. I'm led to believe it's to decrease vibration or maybe dissipate thermal heating. Is the copper colored spot on that one to be worried about? It looks almost like rust. The crack on the other one was immediately visible. It's not deep by any means. I also don't notice any seepage. While there's no bulging on either of them, these features felt worth asking about on these forums. Both of those appear to have a manufacturer which goes by "[ ] KY" It looks somewhat like OKY. They're 1000uf 25 volt 105C rated. There's a reference to "4(7) 9Y".

    Sadly (inconvenentily) I do not as yet have an ESR meter or capacitance meter. I do have a old meter of sorts, but I don't think it'd be of any use. It's named GB Instruments GMT-12A. Here's the manual:
    http://www.ps2netdrivers.net/manual/...mt-12a/#manual

    Neither do I have the other things I need: soldering iron, soldering wick or solder sucker, solder wire. So right now I'm just digging for information. I may also open it up again and take a look at the underside of the boards, as I've told they can show damage too. I also want to figure out how to get cleaner shots with the camara.

    Some questions I have:
    1) Are the capacitors available in the shop on this site rated as being low ESR?
    2) Do I HAVE to get low ESR capacitors? My local radio shack has some 1000uf 35 volt electrolytic capacitors, but it doesn't look like they're low ESR.
    3) If I buy these on badcaps.net, what should I get? And can I use paypal without debit/credit card?
    4) What tools do you recommend I buy to do this job, keeping in mind I'm VERY budget conscious. I might have a $50 budget for this, at most.

    EDIT: Sorry should I have put this here(?):
    https://www.badcaps.net/forum/forumdisplay.php?f=30
    Last edited by forswitch38; 10-02-2015, 07:43 PM.
  • japlytic
    Badcaps Legend
    • Oct 2005
    • 2086
    • Australia

    #2
    Re: Monitor: Sony SDM-HS74P LCD

    Welcome to the forums, forswitch38!

    Originally posted by forswitch38
    2) Do I HAVE to get low ESR capacitors? My local radio shack has some 1000uf 35 volt electrolytic capacitors, but it doesn't look like they're low ESR.
    Yes, the electrolytic capacitors have to be low-ESR units, except for the primary side 400/450V unit - what is the series of this unit e.g. KMG?
    I see that the electrolytic capacitors are Chemi-Con units and all of them are mid brown - are there any which are of an unusually dark brown?
    My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.

    Comment

    • Sparkey55
      Badcaps Legend
      • Jan 2010
      • 1523
      • USA

      #3
      Re: Monitor: Sony SDM-HS74P LCD

      From what I can see in photo 3, the cracked aluminum can. I would venture to say that the quality of the aluminum is low. The internal can pressure should have forced the vents to open; not to cause a crack to form first. Just my two cents.

      Comment

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