Samsung LE32S73BDX No power not faulty caps

[PlainBill]

Re: Samsung LE32S73BDX No power not faulty caps

Hi the previous post were only 5 mins apart I must have started writing mine as you posted yours so I completely missed it

There are 3 fuse positions f1-3

f1 reads & f3 give a 20 ohm reading so test good.

Recheck that. A 5 Amp fuse should read much less than an ohm. Actually lead and contact resistance may increase the reading to about .5 ohm.

F2 however doesn't actually have a fuse across it and there is just a diode in between the two pins where the fuse should be.

It's not a diode. It may be a zero ohm jumper, or it might be a fuse with a 'D' current rating.

right, the CCL controllers full IC code is: MSC 1692IPW 0549B

the schematic for the controller is located here;
http://pdf1.alldatasheet.com/datashe...LX1692IPW.html

thanks, Reidy-

Excellent!!! I had tried identifying it and found a notice from the same vendor stating the datasheet was confidential.

Actually, I suggest leapfrogging a number of preliminary tests and trying a functional test. Hook up the inverter, CCFLS, etc. but leave the back off the TV so you can see the back of the panel. There are usually a number of openings so you can see if the backlights turn on briefly. Plug in the TV and if necessary hit the power button so the standby led goes off. Was there a brief flash of light from teh back of the panel (working in a dimly lit room will help). The flash may be very brief, many inverters are set up with a very brief (much less than a second) on period if a fault occurs.

If there was no flash, make the following readings in a well lit room. You don't want to short out anything with a probe. You will be reading DC voltage. (Top refers toward the top of the picture of the inverter; it's probably rotated in the TV). TV plugged in to power, standby light off.

1. From pin 7 of CN1 (Gnd) to pin 1 of CN1

2. From pin 7 of CN1 (Gnd) to the top of F1

3. From pin 7 of CN1 (Gnd) to the top of F2

4. From pin 7 of CN1 (Gnd) to the top of F3

5. From pin 7 of CN1 (Gnd) to pin 20 of the LX1692

6. From pin 7 of CN1 (Gnd) to pin 6 of the LX1692

If you DID see a brief flash, the odds are one of the inverter transformers has shorted turns. I would expect all secondaries match to within a percent or two. Fortunately, these are easy to measure. The transformer pins are numbered in a counterclockwise pattern. Pin 1 is marked by the white dot, which coincidentally corresponds to the number on the pc board. Pins 1 and 8 are the ends of one secondary; pins 4 and 5 are the other secondary. Pins 2 and 7 are one primary, pins 3 and 6 the other. If I recall correctly, the resistance of the secondaries are about 900 ohms. Measure them all, record the numbers. You are looking for one which is slightly (more than 2%) different. Of course, do this with the TV unplugged. We don't like 1000 volt surprises!

PlainBill

[reidy-]

Re: Samsung LE32S73BDX No power not faulty caps

Right well I'm glad you commented upon this (F2 fuse) because I had assumed it was a diode and so when I measure a very large impedance I didnt think twice about it (rather stupid in hindsight)

so what do you think? just flat out bridging it (I dont have any micro fuses) or I might just vertically stitch a full size onto it for testing.

I have never come accross a 'letter based fused rating systems could you explain what they refer to I tried to see if the internet could elborate but cant seem to find anything.

edit: It measures around 10mega ohm depending on how much pressure I put on the pads so it must be knakered ill desolder for further analysis. Fingers crossed this will put the TV back into opperation.

[reidy-]

Re: Samsung LE32S73BDX No power not faulty caps

Quick message off my iPhone
TV works I owe you several beers Bill, top bloke!

[PlainBill]

Re: Samsung LE32S73BDX No power not faulty caps

Several manufacturers produce SMT fuses that resemble resistors, like this one did. Rather than identify it with '1A / 67V' they mark it with a single letter. By looking up the letter on the manufacturer's datasheet you can determine that a fuse with an 'M' on it is a 2Amp fuse.

The joker is that not all series of SMT fuses from all manufacturers use the same code. And of course, I wasn't sure if F3 read 'D' or '0', because there are zero ohm resistors - jumpers.

Glad it's working. I'll accept the beer, but only if it's cooled to a decent temperature. I've read 'Tales of the White Hart'.

PlainBill