sharp lc32sb24u bulb / inverter problem

[laikm]

Re: sharp lc32sb24u bulb / inverter problem

after shorting C7558, the display is on for less than 20 secs and then off again .No more sound.

measure resistance of primary and secondary high voltage installed and found no open circuit and significant resistance difference. what will be next step ?

[CapLeaker]

Re: sharp lc32sb24u bulb / inverter problem

You can override the Error Detection by jumping C7558 which is close to IC7501 to test further. This will override the Error Detection IC

For testing yes, other than that it is not such a good idea.

[budm]

Re: sharp lc32sb24u bulb / inverter problem

It is not just for error detection, it is also protection you will do that only for testing purpose since you will no longer has protection circuit or what will happen as in post 42, seen that happen many time from people who did what they read on internet.

[electronicsurplus]

Re: sharp lc32sb24u bulb / inverter problem

Ive attached 3 pictures. The first is a view of the whole back of the board. The largest IC with 3 pins a regulator, the 10 pin is the AC/DC converter IC, and im not sure what the small IC does. The design of this inverter doesnt lend itself to testing very well since all the transformers are in parallel.

There are 2 groups of 2 FETS which provide the 2 AC inputs for the transformers and each group is gated by the AC/DC IC. The FET's appear to convert 13v power to the AC voltage. I have tried testing the AC voltage while the TV is on (for about 5 seconds), but do not get any readings. But the TV does light up, so obviously its an error in how im trying to measure it.

I also included a picture of the connector, because im wondering if theres any way to fool the err pin? (I assume its what reports the error to the main board), Like would cutting the wire work, or does the err pin transmit a steady voltage to the main board to prove everything is working.

You can override the Error Detection by jumping C7558 which is close to IC7501 to test further. This will override the Error Detection IC

[ipfreely]

Re: sharp lc32sb24u bulb / inverter problem

I dunno if this will work but here is a pic of the burn I put on imgur. Yikes!

http://imgur.com/prkWNq2

[ipfreely]

Re: sharp lc32sb24u bulb / inverter problem

This thread has been very helpful on a couple of occasions for me. I jumped the capacitor and got the tv going which was great. It worked well for about a year.

HOWEVER, two days ago it started to burn and last night it got so bad I thought it might actually flame up. So I decided to go further on the other links in this thread and inspect the bulbs. The burned out one had actually broken on the ground end and the hot side completely burned thru the board its mounted to and was completely black. The white backing material of the light box was a little melted as well.

What I decided to try is removing the pair that run together and see if it still burned. It did not. (amazingly the sockets are still fine and work if I swap bulbs to them fyi) I just used it for a couple hours and it is fine but has a dim band in the middle. So it seems to be possible to use these without buying new lights but you have to remove a full pair or it will burn. That is why it has a protection circuit apparently.

I'll post again if any further damage occurs but I wanted to add this note for future hackers who decide to just run it jumped like me. If you smell smoke don't ignore it!

[bans25]

Re: sharp lc32sb24u bulb / inverter problem

I need a bulb, anyone have one to spare? They want over $33 bucks for a bulb on the sites now.. note sure if it will even fix my TV. I did confirm one is out so I hope this is it! RLMPLA029WJN1

[freakytiki4u]

Re: sharp lc32sb24u bulb / inverter problem

Just wondering if you ever found the part# for these bulbs? If you still need it, the part# is RLMPLA029WJN1 (old thread I know, but ya know lol)

Well, i officialy wasted a bunch of time.

Note to self: never forget to return to the normal error checking path >

if you have a 2 second to black
1) check inverter transformers
2) check bulbs


... once i fixed the transformer that i had damaged when testing i spend 2 days testing every component on the board ... when all i needed to do was check the bulbs. Sure enough 1 of them is bad. And since theres 2 bulbs in a row for each transformer, i can be certain its just the bulb and not the transformer.


So where do i order bulbs? the service manual luckily gives a list of all the stats it needs ... 1700v, 150hz or something,

Oh and additionally, i will give sharp credit for this being an awesome frame design for the screen. The lcd is attached to the outer metal frame, so you dont have to worry about the loose floppy screen cracking, its like taking the lid of a jar, it fits perfectly snugly over the light box.

[Levardw]

Re: sharp lc32sb24u bulb / inverter problem

I would like to purchase a bulb

[TopFuel]

Re: sharp lc32sb24u bulb / inverter problem

Hey Monkeyflows I could use one of those bulbs.

What do u want for one?

topfuel388@gmail.com

[Monkeyflowz]

Re: sharp lc32sb24u bulb / inverter problem

To confirm the confirmation-Just did this repair also on a dumpster tv..1 sec blink.....

Lamp size: just for my curiosity, 3.4x705mm (glass only measured per ccfl mfg tutorial) I imagin 4mm might fit. There is some play in the length at the ends in original lamps, around 5mm total so a tiny bit longer would still fit. Ends are like a .250" glass fuse set-up.

Replaced 6 bulbs for $18. From Sharp LC32sb23u(not 24u) found on C/L as non working.

$18 invested and now have nice tv for my spare room.

I have 3 bulbs, good LCD screen, diffusers, and mainboard leftover if someone needs them. SMPS was shot (commercial power transformer strike), Old lady said it was only 15 months old when it was keeled.

Also, you can do a white screen input and see bad lamps before taking it apart.

Pics below of bad and good lamps.

sorry for bring the thread back,where did you buy these bulbs from? i need at least 3

[Lrdsatyr8]

Re: sharp lc32sb24u bulb / inverter problem

Hey all... I just picked up a LC32SB24U set from teh junk yard and found this forum and have been trying several of the suggestions... but here's what's been happening. When i first got the set, I plugged the power cord into the wall and turned it on. I got a descent display for anywhere from 5 to 12 seconds and then the set would shut off by itself and the power light would flash green once a second. I tried the VOL- and INPUT button to reset but no luck... So I figured like so many here have stated I probably have a bad bulb (still waiting for one to arrival by mail). While i'm waiting, I figured i would try to jump the capacitor at C7558 (Nasty little bugger to find... almost in the middle of the board) on the power board and in so doing I may have jumped the connection right next to it (would love a closeup photo of that area to see for sure). I tried the set again and still the same problem. I found that if I changed the imput channel to like INPUT4 with a black screen I could access to tv menu. So I brought it up and found the option to update the firmware. Then I got the bright idea to check for updates from the sharp site. I copied the file from the Sharp site to a flash drive and plugged it in. Turned the set back on and navigated thru the menus and began the update proceedure. Everything seemed to be going fine. The set recycled off and then i tried turning it on again. But this time, nothing. Not even a flicker of life on the screen. It didn't even try to turn the screen on. The power light didn't blink at all. However now i get something new. On the back of the main board in the middle, a small light will begin to flash on and off. So what am I doing wrong... and will the blub replacement fix the issue when it comes? Any help would be appreciated!

[walking]

Re: sharp lc32sb24u bulb / inverter problem

To confirm the confirmation-Just did this repair also on a dumpster tv..1 sec blink.....

Lamp size: just for my curiosity, 3.4x705mm (glass only measured per ccfl mfg tutorial) I imagin 4mm might fit. There is some play in the length at the ends in original lamps, around 5mm total so a tiny bit longer would still fit. Ends are like a .250" glass fuse set-up.

Replaced 6 bulbs for $18. From Sharp LC32sb23u(not 24u) found on C/L as non working.

$18 invested and now have nice tv for my spare room.

I have 3 bulbs, good LCD screen, diffusers, and mainboard leftover if someone needs them. SMPS was shot (commercial power transformer strike), Old lady said it was only 15 months old when it was keeled.

Also, you can do a white screen input and see bad lamps before taking it apart.

Pics below of bad and good lamps.

[Onlygains]

Re: sharp lc32sb24u bulb / inverter problem

Just to close this out... I can confirm that part # RLMPLA029WJN1 is correct and works. I ordered from partstore.com $22 shipped. The fix was incredibly easy. The instructions from the fixya link I shared in post #27 was spot on. Thanks to all and especially Allen Bennett at fixya for the part # and perfect instructions. TV is now working flawlessly.

A lot of fun and my first TV repair. Now on to the Samsung 46" with bad capacitors.

[Onlygains]

Re: sharp lc32sb24u bulb / inverter problem

LOL, not only did I see it, I was the one who posted it!

Problem is it's for a different model and I'm not certain it will fit.

[killian6pk]

Re: sharp lc32sb24u bulb / inverter problem

Electronic Surplus, I have already done that. I know what the problem is. It's a bad CCFL bulb. The problem is I can't find an OEM replacement. I am planning on using MMalloys work-around but was hoping for a picture of the fix as I don't know how to replace the capacitor with the small jumper wire or how to fit a shorting link across the C7558 (smd capacitor).

Did you look at this link, which was supplied earlier in the discussion @ post #27? Jumping anything with a wire is dangerous especially if you don't know what you are doing.

https://www.donberg.ie/catalogue/ori...pla029wjn.html

[Onlygains]

Re: sharp lc32sb24u bulb / inverter problem

Electronic Surplus, I have already done that. I know what the problem is. It's a bad CCFL bulb. The problem is I can't find an OEM replacement. I am planning on using MMalloys work-around but was hoping for a picture of the fix as I don't know how to replace the capacitor with the small jumper wire or how to fit a shorting link across the C7558 (smd capacitor).

[electronicsurplus]

Re: sharp lc32sb24u bulb / inverter problem

Try this

1) unplug the television and leave unplugged for a few minutes

2)hold volume - and Input at the same time

3)plug the television in while still holding the vol- and input buttons.

This will put the television in service mode and allow you to better test and diagnose the problem.

If you press power off and then on the television may remain working but, for an undetermined amount of time from 5 minutes to forever

This is the method we use to test panels and other boards

Electronic Surplus

[Onlygains]

Re: sharp lc32sb24u bulb / inverter problem

Thank MMalloy.

Any chance you could share a photo of your fix?

For others this link provides additional info although not the exact same model.

http://www.tv.quuq.org/forum/index.p...e;topic=2801.0

In summary:

Managed to sort this one out. The lamp error counter had reached 5 which means the set needed to be started in service mode (hold down input and vol - on tv set whilst applying mains until the letter K appears on the screen, after which press vol - and prog - on tv set to get the service menu). Had no joy doing this though because the ccfl driver IC (BD9883 smd) was going into protection mode and preventing the backlight from operating. To get round this problem I overode the protection by fitting a shorting link across C7558 (smd capacitor) located near the IC. The set would now start in service mode.
Found that there are some test patterns available in the service mode one of which is a grey screen. Selecting this option showed the problem. The area across the centre of the screen was darker than the rest indicating the centre pair of ccfl tubes weren`t working. This chassis uses 10 tubes driven by 5 inverter transformers mounted in line with them, so before embarking on a tedious stripdown I ruled out the possibility of a duff transformer by swopping the centre one with one of the others. No change of course, so I dismantled the unit and checked the tubes and their holders for any visible problems. None were apparent but replacing the tubes cured the problem. Just needed to clear the lamp error and remove the link.

[mmalloy]

Re: sharp lc32sb24u bulb / inverter problem

I was able to bring my set back to life by removing the C7558 capacitor and replacing it with a small jumper wire. This capacitor is on the backside of the inverter board (green side). It is located about an inch below the BD9883 chip. It is an extremely small, surface mount component. This keeps the inverter controller chip from getting the backlight error signal that shuts down the power board and initiates the annoying flashing green power LED issue. You will have to reset the error count after doing this by holding the power and input buttons down for a few seconds until the flashing green light is replaced by a steady red light. Definitely an "out of warranty" repair, but better than junking the whole TV.