viewsonic 32in lcd tv power supply broken

lcdtech · Guest

I am working on a N2750W with the same power problem described in the thread. I have not checked the power supply board yet (fsp204-2f01, used also on many 26-32" models), for the following reasons:

1. the service manual says "check voltage on C101 16V if not replace power PCB but if one goes into a special mode (cycles primary colors on the LCD panel, can be entered into by pressing MENU + ENTER + Power button) it seems that the backlights work, colors cycle normally, etc.

2. the symptoms otherwise match exactly what was described earlier in the thread

Before I dig into the fsp2042f01 (or order replacement) can someone please help make sense of this logically? Is it possible that the test mode uses power & main board circuitry different than normal mode? I think I have the schematics of this model (N2750W) including fsp2042f01 and can upload them if needed.

jts1957 · Joined: 24 Nov 2008 Posts: 2476 Location: Far, Far Away

Power supplies need a signal to turn "on." When you put your set into test mode, the power supply gets this signal to turn "on." When you try to turn your set "on" normally, the power supply must not be getting this signal. Usually comes from Main/Logic board. Cool

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train123 · Guest

kezug · Joined: 28 Jan 2010 Posts: 13

Hi...I have just acquired a ViewSonic n3251w and when plugged in, the standby light glows. When I turn it on, it only stays on for 30 seconds. I do get something on the screen (right now blue screen but I do see channel display). Then it shuts off and I have to wait, unplug/plug and it can be turned on again, but only for 30 seconds and then it shuts off.

I do smell a hint of something burning, but nothing major and no smoke.

So, I suspect it is a faulty power supply and will be removing the back panel to see which power supply unit it is (as I understand it can be one of two models).

Question. If I simply replace the power supply with the same (fsp2042f01 or fsp2042f02) will it just blow again in a short while or have the replacement power supplies been "fixed" to now go out so soon?

Also, any of you that have replaced the power supply or the capacitors...how about chiming in and giving us feedback on how your unit is doing and how long its been "living"!

jts1957 · Joined: 24 Nov 2008 Posts: 2476 Location: Far, Far Away

If you want a television that holds up like your prior CRT set did/does, may I suggest another CRT set. Laughing

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kezug · Joined: 28 Jan 2010 Posts: 13

Ok, I pulled off the panel and found this fsp2042f01 power supply.

Have the replacement power supplies been fixed to avoid this same issue of burning out?

I am also wanting to hear from others who have replaced the PS...are you st ill holding up?

Check out this supply unit...its capacitors are bulging or melted.

kezug · Joined: 28 Jan 2010 Posts: 13

CORRECTION

Ok, I pulled off the panel and found this FSP212-SF01 power supply.

Have the replacement power supplies been fixed to avoid this same issue of burning out?

I am also wanting to hear from others who have replaced the PS...are you st ill holding up?

Check out this supply unit...its capacitors are bulging or melted.

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kezug · Joined: 28 Jan 2010 Posts: 13

Here is one more pic as it shows the Model #.

train123 · Joined: 26 Jan 2010 Posts: 88 Location: Canada

Based on what I've read on this site, the FSP212-SF01 is no longer available and has been replaced by the FSP212-SF02. I believe the FSP212-SF02 needs a separate wire harness to make it work with your set. I can't comment on if the replacement power supply is any better but your old one has the same problem that plagues the electronic industry for a long time. Capacitors are greatly affected by age and heat, causing the material inside to dry out. Over time, the cheaper caps tend to breakdown and bulge as shown in your photo. Higher quality caps are made with materials more resistant to heat so will last longer. The electronic industry as a whole has also been plagued with counterfeit parts where you are getting a cheap knockoff. Even the power supply manufacturing companies can not tell the difference until many years later once they start failing. May people just replace the bulging caps with new ones and that usually solves the problem. Judging by your description on how the TV behaves, you changes are good that replacing the caps will fix your problem.