sharp lc32sb24u bulb / inverter problem

[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

[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!

[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

[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

[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.

[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.

[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 ?