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viewsonic 32in lcd tv power supply broken
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PostPosted: Tue Dec 18, 2012 7:55 pm    Post subject: Reply with quote

I changed it the TV still wouldn't energy up all the way and I could listen to something beginning to fry again. I suppose something else is resulting in that capacitor to get beyond capacity. I just went on forward and compensated the $60 to purchase a new Power Provide from ViewSonic. Now I'll just have to delay up to 90 times to get it since they're out of inventory.
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PostPosted: Mon Jan 28, 2013 12:02 am    Post subject: FSP212-3F01 Reply with quote

_ASH_ wrote:
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


Hello,

I have exactly the same problem. Replaced Q7 et ZD4, and retreived standby mode. But when I power on the TV, backlight flash few seconds then the TV shut down with amber diode. I have a ticking noise too.

What happen ? Which is the faulty component ?
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NBE
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PostPosted: Sat Feb 16, 2013 12:29 am    Post subject: N2751W Power supply pinout Reply with quote

Does anyone know what the power supply pinout is? I am sure that my problem is in the power supply, but I have no idea what I am supposed to have where.

God Bless,
Glenn
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NBE
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PostPosted: Sat Feb 16, 2013 12:40 am    Post subject: N2751W Problem Reply with quote

OK, Maybe someone can help me out. I have an N2751W Viewsonic TV, I just bought it used, said it didn't work. No picture, but sound worked OK. I brought it home and powered it up, worked beautifully for about an hour, then the screen went blank. The backlight is still on, and so is the sound, but no picture. Does this sound like a Power Supply issue? I did take the case apart and check the Caps, all look OK. Thanks for any help in advance.

God Bless,
Glenn
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jhsparky



Joined: 05 Mar 2013
Posts: 1

PostPosted: Tue Mar 05, 2013 4:49 pm    Post subject: Re: Repair tip for Viewsonic N3250W or N3235W power supply Reply with quote

jts1957 wrote:
Evil or Very Mad PEOPLE [SZASZ] JUST CAN'T BE BOTHERED TO READ PRIOR POSTS (or just do a "Search" for "zd4"!)

"The answer to MY question couldn't possibly be there already." Evil or Very Mad

JRnTX wrote:
I just repaired an FSP 212-3F01 power supply in a Viewsonic N3250W. I have seen the same power supply listed for the N3235W. This one was totally dead with no 5V standby present. The problem was a shorted internal voltage regulator made up of Q7 and ZD4. The Q7 is a SOT23 size device and appears to be too small and over heats in the design. In this case it shorted from the over heating and that caused ZD4 to fail and shut down a 15V bias supply on the power supply board. I replaced Q7 with a 2N4401 to give it more power capability. Any small NPN transistor with a 25V or higher Vce rating will probably work. ZD4 is a 15V zener diode. Note that there appear to be two or three power supplies used in these TVs. This fix may also apply to similar FSP power supplies such as the FSP 228 but that has not been verified.


After taking your advice I searched "ZD4" here and in google, description was 15volt zener diode, so off I went 45 minutes into town only to be asked "15 volts? which wattage 1/4 watt ..... 1 watt....?" Thanks for wasting my time.
So to ask again, does anyone know the specs on the zener diode "ZD4"?
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jts1957



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PostPosted: Tue Mar 05, 2013 7:19 pm    Post subject: Reply with quote

That's sort of like asking for Goodyear Assurance TripleTred tires for your car and not being sure of the size. Most people would use their common sense and tell the salesperson: "The same size that is currently installed on the vehicle."


Zener diodes are somewhat more flexible. Just get one that is the same (or larger) wattage as the one you pull out. Usually is also the same physical dimensions. Bear in mind that replacing a smaller physical size or wattage with a larger physical size or wattage is also perfectly OK (IF space/time/wallet allows).
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PostPosted: Wed Mar 06, 2013 6:14 pm    Post subject: Reply with quote

jts1957 wrote:
That's sort of like asking for Goodyear Assurance TripleTred tires for your car and not being sure of the size. Most people would use their common sense and tell the salesperson: "The same size that is currently installed on the vehicle."


Zener diodes are somewhat more flexible. Just get one that is the same (or larger) wattage as the one you pull out. Usually is also the same physical dimensions. Bear in mind that replacing a smaller physical size or wattage with a larger physical size or wattage is also perfectly OK (IF space/time/wallet allows).


1st all tires have the size on them glass zener diodes do not.

2nd all tire companies have access to all vehicle tire sizes, electronic shops do not have access to all schematics for all electronics.

3rd physical size means absolutely nothing.

4th a lower wattage can fry the ZD, a higher wattage can fry other components it is feeding. (confirmed by 2 tv repair shops and 2 electronic shops). I am not an expert so .50 for the right component or guess and blow $50. for a new PS.

I bought the full schematics online and now have the correct answer.
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Jamesunshine



Joined: 09 Mar 2013
Posts: 1

PostPosted: Sat Mar 09, 2013 8:23 am    Post subject: Viewsonic tv32 power supply Reply with quote

Hi everyone i was wondering if somebody can help me fix my viewsonic tv power supply FSP228 - 3F01 i change all the bad capacitors already and all i need to change is Q7 but i dont know thats the part number and the name of the parts please help.thanks
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jts1957



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PostPosted: Sat Mar 09, 2013 4:13 pm    Post subject: Reply with quote

IS already on thread.
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train123



Joined: 26 Jan 2010
Posts: 88
Location: Canada

PostPosted: Mon Mar 11, 2013 12:46 pm    Post subject: Reply with quote

Anonymous wrote:
jts1957 wrote:
That's sort of like asking for Goodyear Assurance TripleTred tires for your car and not being sure of the size. Most people would use their common sense and tell the salesperson: "The same size that is currently installed on the vehicle."


Zener diodes are somewhat more flexible. Just get one that is the same (or larger) wattage as the one you pull out. Usually is also the same physical dimensions. Bear in mind that replacing a smaller physical size or wattage with a larger physical size or wattage is also perfectly OK (IF space/time/wallet allows).


1st all tires have the size on them glass zener diodes do not.

2nd all tire companies have access to all vehicle tire sizes, electronic shops do not have access to all schematics for all electronics.

3rd physical size means absolutely nothing.

4th a lower wattage can fry the ZD, a higher wattage can fry other components it is feeding. (confirmed by 2 tv repair shops and 2 electronic shops). I am not an expert so .50 for the right component or guess and blow $50. for a new PS.

I bought the full schematics online and now have the correct answer.


jts1957 is correct, your local shops are not. You might have had 2 shops give you that answer but you need to ask the right question before you get the correct answer. As a Electronic Technologist, I know that that zener's only job in that circuit is to establish the operation voltage of that voltage regulator. Using one too small could lead it to burn out again but bigger is fine. I've fixed dozens of these power supplies and just use a common 1W zener in that location. Also, when it comes to electronic parts, physical size means a lot since a larger size is needed to handle heat dissipation of the higher wattage part. A smaller part usually indicates a lower wattage unless a heat sink is provided to handle the heat. Don't be too hasty is judging the people on this forum, they've likely been doing this for a lot longer than you have.
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