Funai LF320FX4F Power Supply Issue?

[trs71]

Hi,

I'm the pround owner of a Funai LF320FX4F $98 Black Friday Walmart Paperweight. It Turns on for about 3 or 4 seconds sometimes a bit longer, just enough to see a picture, and promptly goes out. I assume it's the power supply PN# BA3AF0F01023.

I could order one off of ebay for $20 but where is the fun in that. The board has nothing visibly wrong that I can see, and of course I can't find any trouble shooting schematics for this thing. Any ideas on a good place to start?

[R_J]

Re: Funai LF320FX4F Power Supply Issue?

You could start by posting some pictures of the boards

[Ltank]

Re: Funai LF320FX4F Power Supply Issue?

If the fuse is blown check the mosfet for shorts to ground. All three legs would be shorted to the
Heatsink

[trs71]

Re: Funai LF320FX4F Power Supply Issue?

I was going to post a picture and I can take one but the Ebay zoom picture is better probably than I can take.

It's identical, nothing burnt or discolored on mine. I can post a pic of top and bottom when I get back if needed, a quick test I believe, shows D608 (by the big cap) to be shorted. The fuse (F602) tested good.

[trs71]

Re: Funai LF320FX4F Power Supply Issue?

PICS


[/URL][/IMG]

[/URL][/IMG]

[/URL][/IMG]

[budm]

Re: Funai LF320FX4F Power Supply Issue?

Can we see the bottom side of the power supply board? The power MOSFET must be on the bottom side of the board which will be strange since it will require heatsink. Also pictures of the whole back side of the TV. It seems to me that this a sub-power supply, not the main power supply.
It looks like LED Backlights TV.

[Caleb]

Re: Funai LF320FX4F Power Supply Issue?

d608 looks like a zener from the board desination, pull it out of circuit and retest to see if it is shorted or something else in the circuit. I fixed a funai last week with only a single failed zener diode, you may get lucky.

[trs71]

Re: Funai LF320FX4F Power Supply Issue?

Sure PCB pic


I only have done some basic repairs on arcade monitor and the such and lcd tv's but this doesn't even look like a power supply to me....

[/URL][/IMG]

[budm]

Re: Funai LF320FX4F Power Supply Issue?

One of those cheap two transistor Osc power supply. Did you check ALL the Diodes on the board for shorts?

[trs71]

Re: Funai LF320FX4F Power Supply Issue?

Didn't see any other shorts, I'll do test again after work.

D654 is a Zeiner, but it shouldn't be conducting both ways (leaking) with an lcd meter diode test should it?

[budm]

Re: Funai LF320FX4F Power Supply Issue?

"D654 is a Zeiner, but it shouldn't be conducting both ways (leaking) with an lcd meter diode test should it?" That ZENER may be connected in parallel with the low Ohm Source resistor, so you need to lift one leg of the Zener and test it again.

[trs71]

Re: Funai LF320FX4F Power Supply Issue?

d608 looks like a zener from the board desination, pull it out of circuit and retest to see if it is shorted or something else in the circuit. I fixed a funai last week with only a single failed zener diode, you may get lucky.

Once D608 is out of the circuit it seems fine, D654 looks ok too. No other diodes test bad on the board.

[Andrew F. Ali]

Re: Funai LF320FX4F Power Supply Issue?

Have observed that Pwr boards with BAXXF0F01022, etc from manufacture FUNAI are poor quality and if you are successful in repairing they don't last too long.

[Caleb]

Re: Funai LF320FX4F Power Supply Issue?

have you checked all the diodes on the reverse side for shorts as well? I can see at least 4

[bammbammfran]

Re: Funai LF320FX4F Power Supply Issue?

your problem might not even be with this power supply board.
Could be the main board or you may have a problem with the led lighting in the panel

I do not seem to see any mention to voltage testing and results
Since it turns on a bit, the voltages should be monitored in off state and on state and after it shuts down

[bammbammfran]

Re: Funai LF320FX4F Power Supply Issue?

Check voltage at the two red areas
use the black circled area as a ground.

Check this power with the board by itself
then plug in the input board (do not connect the actual screen panel yet) and check them again.
then with a video source connected , power on the unit and check them again

If the voltages stay steady and do not drop, the board might be ok
so then we'll have to check power to the panel

[trs71]

Mr

Sorry I haven't got back to testing it till now, family stuff and all.

I tested every thing unplugged and plugged in, (input & screen) and had power of 10.9v on two diodes and 6.5v on the other two at all times. I also (a week ago) went and bought a cheap used power board because of the problem with the previous reversions of it, and of course it does the exact same thing.

Powers on, power light flashes 17 times, I see the Funai logo and...nothing steady power red light, no pic. It seems to be picking up a video signal with a HDMI hooked up to my pc video card. The pc kept recognizing a display being connected.

Thanks for the help so far, with the number of these bought and the failure rate already (from my searching) I'm sure this model will soon pop up quite frequently.

[trs71]

Re: Funai LF320FX4F Power Supply Issue?

Since the power supply seems ok, what should I check next the main board or? Not sure what I can check on there, I get a clear Funai logo for a few seconds and that's it.

[TJVJR]

Re: Funai LF320FX4F Power Supply Issue?

Did anyone find the solution? I have the same model with the same problem .

[trs71]

Re: Funai LF320FX4F Power Supply Issue?

I sure didn't, It seems the voltage was correct for the momnent it was on, but I switched out the power and the main boards with "working" ones, tried disconnecting all the plugs and powered up each time also with no change.