Westinghouse SK-32H240S Continued problems

[retiredcaps]

Re: Westinghouse SK-32H240S Continued problems

I followed PlainBill's advice by
testing the CCFL's by unplugging all but one connector and powering it up in a dark room. I did this for all six connectors and had a flash for each one.
So I assume all six lamps are working.

PlainBill's test above is only valid if the ccfl is completely broken. If the ccfl is completely physically broken, then it won't light. A ccfl can still light up and be bad because it is drawing too much current (i.e. it is near its useful life) or the return wiring is frayed internally.

A inverter PWM IC operates as an "all or nothing". Either all the ccfls work or none at all.

2 seconds to black can be

a) bad caps
b) bad ccfls
c) bad ccfl wiring (especially the return wiring)
d) bad secondary windings on the inverter transformer

More details starting with post #19 at

https://www.badcaps.net/forum/showthread.php?t=10419

Also, see budm's Inverter tester using old CFL

https://www.badcaps.net/forum/showthread.php?t=19987

[Mike95inNJ]

Re: Westinghouse SK-32H240S Continued problems

For this reason, I will replace all three but then again, there's no guarantee.

Hello. Did you get around to replacing all three of the transformers on your board?
If so, did it correct the problem? Please let me know when you get a chance.
Thanks, Mike

[lilmonk3]

Re: Westinghouse SK-32H240S Continued problems

Same problem.. Replaced the bad transformer, but still have the shuts off after 2 sec.
Has anyone found that all three need replaced to cure this?

[selldoor]

Re: Westinghouse SK-32H240S Continued problems

Hi Lilmonk3- did you give up on the Samsung.
It could be one of the other transformers is bad - did you test them all originally- or was one just burnt out? - It could be a number of other things - see retiredcaps post above.
Can you see the lamps - to see if one does not flash on.

[lilmonk3]

Re: Westinghouse SK-32H240S Continued problems

Yes I have put the samsung to the side for now.. Yes one transformer was burnt. I can see all lamps flash.

[selldoor]

Re: Westinghouse SK-32H240S Continued problems

OK. Test all three transformers - here is the link from retiredcaps guide
http://lcdparts.net/TransformerDetai...ProductID=2724
shows you where to test. Set meter on 2000 ohms test as link and post results .
T1 S1-S2 =XXX S3-S4 =XXX
T2 etc etc

[kevinm34232]

Re: Westinghouse SK-32H240S Continued problems

I just picked up this same model TV for $20, it appears to have 2 different issues. The one is a garbled screen with random veritcal lines that appears to be a LCD/or connection issue. Secondly, the backlight comes on there goes off after about 10 seconds.

I suspect one of the transformers as it tests differently then the others, but Im not sure actually what pins to test. I recently got a blue ring tester aswell but do I have to pull the transformer off to see what's what??

The only #'s I can see on the side of the transformer are:
42-M41411P08
LITEON 0739 MC REV A 6

[kevinm34232]

Re: Westinghouse SK-32H240S Continued problems

Ok I took one off just to see how it's layed out.

I tested each primary winding with ring tester and full green LEDS, also resistance was 2.2 - 2.3ohms on each transformer.

Not sure if I measured secondary correctly, seems to be 2 windings with a common pin in the center. Here's results for each one with meter set to 2k, measuring with probe on center to each side of windings.

T303 - .539, .536
T302 - .539, .541
T301 - .538, .541
T203 - .525, .526
T202 - .521, .525
T201 - .541, .541

Did I do this correctly? Also, putting ring tester on same pins lights 1 yellow LED.

[kevinm34232]

Re: Westinghouse SK-32H240S Continued problems

1 thing I just noticed aswell as when backlight goes off TV is still on, but by hitting any of the buttons on the side (volume, etc,) backlight comes right on for about and will stay on if buttons are pressed. This makes me think everything is working but maybe backlight is shutting off for lack of video signal??

[tom66]

Re: Westinghouse SK-32H240S Continued problems

Is there a BL_ON signal going from main to PSU?

[kevinm34232]

Re: Westinghouse SK-32H240S Continued problems

There is 4.3v at BLON, until backlight shutsoff after 10-15 secs, it goes to 0v. But, by hitting one of the volume or channel buttons on side of tv, backlight instantly lights up and 4.3v returns to BLON.

Does 4.3v sound a little strange? And jumping from 5v standby to BLON, keeps backlight on.

[tom66]

Re: Westinghouse SK-32H240S Continued problems

Sounds fine for a BL_ON signal; I'd look at the main board.

[kevinm34232]

Re: Westinghouse SK-32H240S Continued problems

I just hooked up HDMI source, and went thru the inputs until I got sound. Backlight will stay on with the HDMI source I guess it's supposed to shut off BL with no signal.

[tom66]

Re: Westinghouse SK-32H240S Continued problems

Makes sense, so you've fixed it?

[kevinm34232]

Re: Westinghouse SK-32H240S Continued problems

Nope back to original garbled Westinghouse logo on startup, and then random vertical colored lines. On 3 or 4 other tv's I've tried a new t-con board and it turned out not to be the problem, so Im recluctant with this one.

[Dgtech]

Re: Westinghouse SK-32H240S Continued problems

This may seem like a cheesy fix but... it worked on a Westinghouse SK-32H240S.

See here:
http://www.avsforum.com/t/1143881/we...lems-anyone/30

Look at post 34. That's not me but I had one of these sets with the same exact problem and fix. It was one of the cheapest fixes yet.

[MajesticMike]

Re: Westinghouse SK-32H240S Continued problems

I have a Westinghouse SK-32H240S with the same problem as Xavier Renowned and Mike95inNJ (which is “2 seconds to black” But its 2 flashes of the back light. 1 flash shows the ‘W’ logo then another flashes the TV input then backlight stays off. You can see the picture if you hold a flash light up to the screen, and I do get sound.)

I had a burnt transformer and puffed up caps. I replaced the 1 bad of the 3 transformers, and a few bad caps. I've checked most of the caps with ESR meter and the rest seem okay. I checked the transformers resistance on the primary and secondary and there isn’t much difference. I've tested the ccfls with PlainBills method and another of my own. I used an old LCD pc monitor inverter board to light up one ccfl on this tv at a time (and 3 on my old monitor to balance it), and made sure I could get each ccfl on this TV to stay on as long as I wanted, using this method for all 6 ccfls. (Of course I had to feed the monitor a signal from my pc through the VGA port to make it work tho.) I also tried the opposite, lighting different ccfls with this tv inverter board. I hooked 2 of the ccfls on my old LCD monitor to 2 of the connections on each transformer on this TV’s inverter board. And it lit up but still did same thing the tv always did, lit up and went out.
I checked the BL_ON pin and it’s getting 5 volts
I’m not really sure where to go from here… any advice? Am I on the right track? Do you think my way of testing the ccfls was an accurate measure? Is there any other diagnostics I could perform?
Thanks
Mike

[retiredcaps]

Re: Westinghouse SK-32H240S Continued problems

I've tested the ccfls with PlainBills method and another of my own.

1) Thanks for doing some homework and trying the suggestions laid out in the previous posts. You would be surprised at how many people come here and say "help me", but never bother to read and/or try the suggestions already presented.

2) I prefer to test for bad ccfl's using the method laid out in step #5

https://www.badcaps.net/forum/showpo...6&postcount=20

That is, namely using a good ccfl to narrow down the problem.

3) Please report all your secondary windings. Some people incorrectly report their interpretation of the raw data. I'm not suggesting you have done so, but once every 2 weeks, we are led to believe something works when in reality it doesn't.

4) You have 12 blue caps in the inverter section. With power off, measure the resistance between the legs of each one. They should all read open circuit on your multimeter. Report your findings.

5) Was the inverter transfomer replacement an exact match? What was the original part number and what is the replacement part number?

[retiredcaps]

Re: Westinghouse SK-32H240S Continued problems

I've checked most of the caps with ESR meter and the rest seem okay.

BTW, did you test the caps out of circuit with the ESR meter? In circuit readings are not reliable because capacitors could be parallel.

I don't have an ESR, but if I see 2 or 3 bulged caps, all the other caps especially if they are the same brand or a known bad brand like Capxon are replaced (cockroach theory).

[MajesticMike]

Re: Westinghouse SK-32H240S Continued problems

retiredcaps, thanks for your quick reply and help! I had a bit of homework to do in order to get back with you on this matter.

as for the secondary windings:
i'm not sure which is primary and which is secondary when looking at them, but i measured the resistance of the transformers connections from top to bottom and this is what i got. (in circuit)
1. 1765, 1760
2. 1807, 1805 (the new replacement)
3. 1733, 1728

as for the 12 blue caps in the inverter section: Yes they do all read as open circuit with the resistance test. (in circuit)

Was the inverter transformer replacement an exact match?
I think so. Here's the numbers on top:
4301H 746082(GP)__
4301H 922120<GP>- (The Replacement)
4301H 746086(GP)_

Did you test the caps out of circuit with the ESR meter?
Originally, some were in circuit and some were out, so now i went back to all the caps i haven't replaced and pulled them out of circuit to check them.

Unfortunately, the remaining caps are of the CapXon brand. They are all small caps and i have tested each one with capacitance and ESR meters. (out of circuit)
I have 4 caps that are 47uf 50v, 2 caps that are 10uf 50v, and 1 that's 2.2uf 50v
Capacitance, ESR
48.0uf, 0.23
45.4uf, 0.21
45.7uf, 0.24
48.6uf, 0.23

10.3uf, 1.00
10.3uf, 0.82

2.15uf, 2.00