Mulja tv repair portal
Equipment Repairs => LCD TV forum => Topic started by: markie76 on September 02, 2011,15:20:42
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Hi Guys,
Got a Samsung LE32S73BDX/XEU which when plugged in is flashing the red LED in the following sequence;
solid for 3 seconds then 1-1-1-1 <2 seconds> 1-1-1-1 <2 seconds> - just loops
PSU in this is BN96-03775A
Anyone seen this before or know the issue?
Thanks,
Mark
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hi
are the caps in psu ok,then try new eeprom chip
dave
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Hi,
On visual inspection all the caps and components on the PSU look fine.
Does it need a new eeprom - I've read some posts about Samsung eeproms needing to be reset after repair by shorting some pins?
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you can try it find the eeprom on the back of the board it'll be numbered 24c.... something or another usually an 8 pin rather small chip, the dot signifies pin 1 count along to pins 5 and 6 . solder on a wire to both these pins and join the wires . reassemble the set and turn on. The set won't actually boot up at this point. Remove the wires reassemble and turn on as normal . If your lucky this might fix it
Good luck !
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Taken from a thread by " Contrast John " so thanks to him :
On this model the eeprom in question is IC 1803 (24C256) 8 pin smd and is located on the underside of the main board near the common interface. The clock and data pins are pins 5 and 6 and are identifiable by the 100 ohm smd resistors connected to each of them. Fit a shorting link (on long wires) between the pins. Reassemble the chassis. Switch on and then remove the short. Bring the set out of standby.
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your lucky I happened to have the service manual lying from earlier something else you might want to try.
Taken from manual:
It is possible to over ride the lamp error detection circuit and force the set to power up. To enable this feature proceed as follows:
connect ( short ) pins 2 and 4 of the main board connector CN 1101.
It's very possible you could have a lamp error issue this will allow you to get the set operational and see whats going on good luck !
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your lucky I happened to have the service manual lying from earlier something else you might want to try.
Taken from manual:
It is possible to over ride the lamp error detection circuit and force the set to power up. To enable this feature proceed as follows:
connect ( short ) pins 2 and 4 of the main board connector CN 1101.
It's very possible you could have a lamp error issue this will allow you to get the set operational and see whats going on good luck !
This sounds promising except there isn't a connector CN1101 on the main board :(
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Taken from a thread by " Contrast John " so thanks to him :
On this model the eeprom in question is IC 1803 (24C256) 8 pin smd and is located on the underside of the main board near the common interface. The clock and data pins are pins 5 and 6 and are identifiable by the 100 ohm smd resistors connected to each of them. Fit a shorting link (on long wires) between the pins. Reassemble the chassis. Switch on and then remove the short. Bring the set out of standby.
There is no 'IC1803' on the underside of the mainboard - the only 8-pin IC on the underside of the main board is 24C32WP - IC3004
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That'll be it most chips that start 24c are eeproms. For the lamp out bypass on the model I was looking at was the socket on the main board that connects to the power supply and your right it wasnt cn1101 it was cn 1001 but it still worked !
Attached is the data sheet for th eeprom with pin outs
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Yes there is a CN1001 connector going from PSU to main pcb.
With regards to the eeprom reset - if I reset it (wipe it) do I have or how do I re-save the data that is supposed to be in there?
Earlier I had another look at it. Tested the 3 fuses on the inverter and they all seem fine as do the other components with a visual inspection.
I powered it up and upon listening to the PSU closely - ie ear about 5cm away from it, you can hear a feint click (on the 2 second red LED pause) then for the 4 flashes there is a feint fuzzy buzzing noise.
So I think I will hold off reseting the eeprom for now.
Is the protection overide (pins 2 & 4) worth doing? Is there any risk?
I'm going to test each of the psu caps.
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I don't suppose you can say anything's 100 % risk free but since that procedure to override the lamp out error is in the manufacturers service manual I gotta assume they believe it to be fairly risk free as for the eeprom I believe it only resets the variables ie back to factory settings it doesnt actually wipe the chip
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hi,do you have +24v for the inverter?if missing,replace F9222L i.c. usually defective.
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hi,do you have +24v for the inverter?if missing,replace F9222L i.c. usually defective.
Thx for your post. I know its been a while but only just got round to this again.
Should I expect it to be trying to send power to the inverter if it is in red flashing LED state?
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Hi Markie ..
I usually fit a new blank eprom ...which is written after fitting and powering up for the first time after its replaced ..
Also ..if I run out of new blanks ..I've found removing the eprom and flashing it full of FFs.. ie... erasing it ..(after I've read its contents of course ..always handy to have a backup plan)...is an effective alternative ..
Never done this yet on a 32 inch ...but many times on its big brother 42inch LCDs
rgds
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UPDATE
1. I tried shorting pins 2 and 4 of the main board connector CN1101 - didn't seem to have any effect, when it was powered on the red LED just flashed same as before.
2. I connected pins 5 & 6 together of the eeprom, then plugged it in, the red LED flashed quickly (3-4 times a second) I counted to 10, powered down, removed the connection and plugged in, the red LED flashed as before and nothing else happened.
3. I measured the 24v outputs to the inverter and they fluctuated between 2.45v to 3.2v
When powered on and the red LED is flashing if you get close to the PSU you can hear buzzing and very feint clicks sort of in time with the LED flashes - but you have to be close (5cm) and they are feint buzzes & clicks.
What shall I try next? Can I do any tests to check the F9222L?
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ticking sound and pulsing power led in the same rythm -> PSU tries to start up but can't.
replace startup cap (usually 47µF 50V). Or better yet, replace *all* the caps except the 400+V mains filter.
Samsung is notorious for using absolutely crappy Samwha and Sam Young caps throughout the whole PSU to make sure these things (Plasma/LCD TVs and Monitors) fail (somewhat) shortly after the warranty runs out with normal use. They don't have to be bulging on top to be bad (dried up a.k.a. cooked and/or ESR shoots through roof)
Also check for obvious shorts to ground on all the PSU outputs (which would also keep it from starting up)
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hi,
ive'd change the psu board.perfect.
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ticking sound and pulsing power led in the same rythm -> PSU tries to start up but can't.
replace startup cap (usually 47µF 50V). Or better yet, replace *all* the caps except the 400+V mains filter.
Samsung is notorious for using absolutely crappy Samwha and Sam Young caps throughout the whole PSU to make sure these things (Plasma/LCD TVs and Monitors) fail (somewhat) shortly after the warranty runs out with normal use. They don't have to be bulging on top to be bad (dried up a.k.a. cooked and/or ESR shoots through roof)
Also check for obvious shorts to ground on all the PSU outputs (which would also keep it from starting up)
Replaced all capacitors and made no difference.
Haven't found any 'obvious' shorts...
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....if this is the set that uses this psu board ...
The F9222L is always a suspect ..
rgds
Evan
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....if this is the set that uses this psu board ...
The F9222L is always a suspect ..
rgds
Evan
The PSU is BN96-03775A - slightly different layout to your pic but it does have a F9222L - as these are about £8 - before ordering is there an easy test I can do on it to verify if it is suspect/blown?
Thx
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....if this is the set that uses this psu board ...
The F9222L is always a suspect ..
rgds
Evan
The PSU is BN96-03775A - slightly different layout to your pic but it does have a F9222L - as these are about £8 - before ordering is there an easy test I can do on it to verify if it is suspect/blown?
Thx
Not really m8 ..
But ..I always keep at least 1 in stock ...their reliability is always suspect in situations like yours..
If you don't use it now ...eventually ..you will ..
My advice ...take the plunge and order one..
rds
Evan
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Samsung Power Supply # BN96-03775A
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....if this is the set that uses this psu board ...
The F9222L is always a suspect ..
rgds
Evan
:13:
Hi Evan,
You were spot on - new F9222L and tv is back up and running :13:
Thx
Mark