Funai LF320FX4F Power Supply Issue?

[TJVJR]

Re: Funai LF320FX4F Power Supply Issue?

Well the hairdrier trick isn't working anymore . Now all it does when powered on ( or plugged up )is flash the power indicator light several (17 if I counted right ) times. No light from the screen or Funai start up screen at all . Has any one found a solution for this ?

[toddw65]

Re: Funai LF320FX4F Power Supply Issue?

The set I had stopped working again too so I sent it to tv heaven. On to the next one.

[johniwad]

Re: Funai LF320FX4F Power Supply Issue?

Someone dropped this TV off with me and I've had a hell of a time trying to figure out what's wrong with it. I'm getting low output voltages on the 21v and 13v lines. The 3v line is fine. I've tested just about everything I can on this board and still can't figure out what's pulling these voltages down. I ordered some 470uF 100 caps as a last ditch effort attempt to fix this board. Only thing I can think of is that maybe there are a few bad smd components that I haven't tested.

Below are a few known components that usually fail on this board even though all tested good on my board.

Q601 TK7P60W
D608 1N4753A
D660 SL431A-AT
F602 2.5A 250V

[budm]

Re: Funai LF320FX4F Power Supply Issue?

21V and the 13V will about half in standby until the main board send out the PS-ON command to shift the Voltage up to the indicated Voltage.

[johniwad]

Re: Funai LF320FX4F Power Supply Issue?

I jumped the power on with a resistor. Here's what I'm getting:

1.9v on 3.3v
2.8v on 13v
0.5v on 21v on one side of the board and negative volts on opposite side

I'm thinking there is a problem on the 21v line. I also notices a high pitch sound I believe is coming from the transformer.

[budm]

Re: Funai LF320FX4F Power Supply Issue?

These power supply will squeal when too much load or due to shorted/leaky diodes.
You need to check ALL the diodes and Zener diodes in that power supply board.
Disconnect the cable going to the main board to see if the 21V will come up, also check the resistance between the 21V pin and GND pin to see if it shows low resistance<100 Ohms with and without the power supply board connected to the main board.

[johniwad]

Re: Funai LF320FX4F Power Supply Issue?

Checked all diodes on top side of board by removing one lead to make sure. All top side diodes are good. There are a few SMD diodes on underside of the board that are questionable but that maybe due to the fact they where tested in circuit. With or without main board connected I get no 21V. Also no low resistance between 21V and GND. Maybe one or more SMD diodes are bad or something is breaking down under load.

[johniwad]

Re: Funai LF320FX4F Power Supply Issue?

Just wanted to touch base on my findings about this TV. I finally got it working. It ended up being one LED being out. I couldn't tell because I was too lazy to tear TV apart. Even though I tricked the back lights in turning on there was still one bad LED keeping it from turning on. The only problem with this TV now is that with input menu pulled up it shows all inputs as being HDMI 1. Even though all inputs show up as being HDMI 1 they still work. I'm thinking this has to do with the eeprom. Does anyone have the eeprom dump for this TV?

[boozy79]

Re: 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.

OK doing theses tests, I had the 10.9 on 2 of the diodes, on the other 2 I had the 6.5 I measured while i pressed the power and the 6.5v jumps to 13v for about 5 seconds, I get the screen flash and it returns to 6.5v...

[DrewDraKula]

Re: Funai LF320FX4F Power Supply Issue?

I got my hands on one of these T.Vs. The funai lf320fx4a.
I have a VERY EASY solution to check if it is the LED in the back light strip causing the issue. This is the ONLY real solution to verifying a bad LED as an LED may actually light up when bad. Such as attempting to turn the television on while looking at the LED strip. You may see all light up when one is actually bad.
The solution(and cheezy fix if so wanted) is to simply find the plug that sends the power to the backlight."C1001" Then take a standard white LED(through-hole) with resistor for current limiting, and place the leads in the plug. Do not unplug the plug. The LED you have now attached properly with the positive and negative leads(Anode/Cathode) going into the plugs Pos and Neg terminals, will light up and stay on while the backlight/ thus TV, will remain on as well. This is an easy verification that the issue is your LED backlight strip and for those that wish to be lazy, this can be their fix as it will keep things going till you have another issue. (Which will come about with this set)

[lucky13]

Re: Funai LF320FX4F Power Supply Issue?

I got my hands on one of these T.Vs. The funai lf320fx4a.

The solution(and cheezy fix if so wanted) is to simply find the plug that sends the power to the backlight."C1001" Then take a standard white LED(through-hole) with resistor for current limiting, and place the leads in the plug. Do not unplug the plug. The LED you have now attached properly with the positive and negative leads(Anode/Cathode) going into the plugs Pos and Neg terminals, will light up and stay on while the backlight/ thus TV, will remain on as well. This is an easy verification that the issue is your LED backlight strip and for those that wish to be lazy, this can be their fix as it will keep things going till you have another issue. (Which will come about with this set)

So, you saying basically add this in parallel with the LED strip inside. This draws enough current to keep the BL on. This also allow one to inspect the LEDs inside the panel to see how many are dead.

I did cheezy fix like this before on LCD monitor with the older fluorescent tubes too. One of the two top tube was open and shutting off the backlight. I found a tube from another LCD monitor that is slightly smaller in size. I had the "lamp" externally hanging inside the monitor, above the electronics. It provided a nice wall wash to a dark room too.

[martymcfly]

Re: Funai LF320FX4F Power Supply Issue?

I've got a sanyo/funai model fw32d06f. Board is a ba4afsg0201. Basically dead. No power. No standby. I was told it took a "power hit". I have continuity at the fuse and all the caps look good. No bulging. Although I haven't gone through each one with my cap tester yet. I'm getting 120v up to the diodes on the hot side. Just looking for some advice on where to go next?

[vinceroger69]

Re: Funai LF320FX4F Power Supply Issue?

I've got a sanyo/funai model fw32d06f. Board is a ba4afsg0201. Basically dead. No power. No standby. I was told it took a "power hit". I have continuity at the fuse and all the caps look good. No bulging. Although I haven't gone through each one with my cap tester yet. I'm getting 120v up to the diodes on the hot side. Just looking for some advice on where to go next?

As this is a diffrent tv model number it maybe best to start a new thread please also post some good clear pictures of the boards used in your tv, as we dont have your tv in front of us we need clear pictures we can zoom in on them etc and they we can advise you more.
Also if this took a power hit a lot of the time if a source was connected ie aeriel its a mainboard fault but we do need to rule out the power supply first.

[martymcfly]

Re: Funai LF320FX4F Power Supply Issue?

will do .... thanks!

[colt45lush]

Re: Funai LF320FX4F Power Supply Issue?

I am having a issue where there is no power led and nothing turns on. Plug in the cord and there is humming from the power supply. When I disconnect the ribbon cable to the main board the humming stops. With the main board removed I check the main board grounds usb, coax and hdmi with the 21v pins and get a resistance of .6 ohms. I now have a used one from ebay and the same test yields 6.2 ohms. Are both boards shorted out and causing this issue?

By the way I have pulled the power supply caps and diodes and checked them out of circuit.
This is a DS2 s/n Tv was there a updated board that works in this version .

Thanks for the help

[colt45lush]

Re: Funai LF320FX4F Power Supply Issue?

Anybody? I'm new to electronic diagnostics.

[budm]

Re: Funai LF320FX4F Power Supply Issue?

Check C3214 on the main board to see if it shows low resistance or not.
You may have the similar problem as this one:
https://www.badcaps.net/forum/showth...214#post703358

[colt45lush]

Re: Funai LF320FX4F Power Supply Issue?

I ended up fixing the board by pulling components from the one until I found the short. I then applied what I had learned to the Ebay bought one and fixed it. They were both A3AFNUH BA3AFCG0201 4 boards and they both had the same problem. Ceramic cap C3022 4.7 . I'm pretty sure that it was micro farad.