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_ASH_



Joined: 09 Dec 2011
Posts: 8

PostPosted: Fri Dec 09, 2011 7:49 pm    Post subject: viewsonic 32in lcd tv power supply ( Reply with quote

Hi Guy's please go steady with me as I am no electronics expert,

I have a viewsonic 32in lcd tv power supply (Model: N3260w) that has a power board problem.

I have replaced capacitors CS25, CS24, CS19, CS22, CS21, CS20 & CS 28 (none of them had blown but were bulging, so I thought I would replace them).

However, upon further inspection I have found that on the reverse side of the board, ZD4 & R65 have blown (please see pictures) [img]http://gallery.me.com/alan.harrison#100001/2&bgcolor=blackl[/img]
[img]http://gallery.me.com/alan.harrison#100001/1&bgcolor=blackl[/img]

I am after some advice please on what these are (I assume a Zenner Diod & a resistor), what values and where I can buy these from (I am in the UK).

Many thanks in advance for any help.
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sat Dec 10, 2011 2:57 am    Post subject: Reply with quote

Did a search and found this kit in UK that shows some values..may have other problems though and just may be cheaper to buy the entire board?
http://www.chsinteractive.co.uk/pdf_data/KT41.pdf
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_ASH_



Joined: 09 Dec 2011
Posts: 8

PostPosted: Sat Dec 10, 2011 9:54 am    Post subject: Reply with quote

Many Thanks..
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Sun Dec 11, 2011 11:09 pm    Post subject: Reply with quote

http://forum.eserviceinfo.com/viewtopic.php?t=29325&highlight=n3260w

There's plenty here.
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_ASH_



Joined: 09 Dec 2011
Posts: 8

PostPosted: Thu Dec 15, 2011 12:57 am    Post subject: Reply with quote

Hi Guy's... I have replaced the parts and all is working now (thanks for all input), however I do hear a slight ticking noise coming from the power supply (sounds like a relay or something).

I don't want to get my ear to close as I don't want a big electric shock... lol

Has anyone any ideas what this can be??

Many thanks again.

ASH
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_ASH_



Joined: 09 Dec 2011
Posts: 8

PostPosted: Mon Dec 19, 2011 2:16 am    Post subject: Reply with quote

Hi Guy's... Someone please help me.

I have replaced the following:
ZD4, CS21, CS22, R65

Everything worked fine but with a ticking noise (about every second), I then checked the power supply & ZD4 was really hot (to the point it had broke the solder, I now have the problem where if ZD4 is soldered in or desoldered and power it up, the light flashes red, Amber, then green, then straight back to red. but if I keep pressing the standby button (about 10 times) the green light stays on and the tv powers up.

Can someone please give me an idea where to look as I have been therough the board several times and can't see anything wrong.. I would appreciate help ASAP as I need to sell this to make some space.

Many thanks in advance

ASH
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jts1957



Joined: 24 Nov 2008
Posts: 2472
Location: Far, Far Away

PostPosted: Mon Dec 19, 2011 3:04 am    Post subject: Reply with quote

You DID read ALL 24 pages of the thread minnie referenced? All about ZD4; Q7, etc.?
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Mon Dec 19, 2011 3:28 am    Post subject: Reply with quote

Alan,
Without a schematic it is not going to be easy. Did you follow the link that minnie posted ? There is a good bit of discussion there that could be helpful.
Going back to your problem;
While I am not familiar with the specific circuit, based on your description, it sounds like the zener is trying to clamp too much of a voltage on that rail?(perhaps something else is shorted or leaky on that same circuit prior to the zener causing it to overheat and eventually fail?)
The ticking sound is probably related and more likely coming from a coil or a transformer in the same circuit. There seems to be a thread about a surface mount Q7 that also goes out? Did you follow all the parts listed on that kit?
Go back thru the thread and may want to see if you can contact someone like; [email protected]. ---not sure if it's still a good email?
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train123



Joined: 26 Jan 2010
Posts: 88
Location: Canada

PostPosted: Thu Jan 19, 2012 1:12 pm    Post subject: Reply with quote

I see _ASH_ has posted that he was successful with his repair on the main thread dealing with this problem "viewsonic 32in lcd tv power supply broken". I'm glad he was able to use some of the knowledge the members have posted.
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mostlyHarmless



Joined: 31 Jan 2012
Posts: 1

PostPosted: Wed Feb 01, 2012 1:24 am    Post subject: Viewsonic TV issues Reply with quote

Hi all;

I've read through several threads here, here and think I might have one of these power supply issues on my fiance's TV.

I think I can manage the swap out (or even repair) of the PS, but before I go down that road (or before I even try to take apart her TV to test the PS), I'd like your opinion on whether the symptoms could be a PS problem.

Symptom 1: Erratic, spontaneous change in video input (e.g., from Video, to HDMI 1) without any input from the remote.

Symptom 2: Menu listing for one of the video inputs changes between video or YPbPr/YCbCr (maybe this is normal, but I don't recall).

Symptom 3: TV shuts down, but green power light stays on.

Again, many thanks for the info posted here -- if I manage to save the TV, I'll be a hero!
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