LCD TV SHARP LC-32SH340E can't start

[andrasin]

Hi, I have LCD TV SHARP LC-32SH340E. There is 17MB60-4 mainboard. The problem is that if TV is on stand-by, front LED flashes. When I try to turn it on, LED starts to flash little bit faster, takes 5 seconds and than it falls back into standby mode and LED flashes slower again. Display never doesn't lights up. Do you have any ideas what can be wrong and what should i try to do?

[tom66]

Re: LCD TV SHARP LC-32SH340E can't start

not a real Sharp - all VESTEL junk inside ("official licenced product"). It is a common protection fault with mainboard or PSU.

Two major causes:
- bad main board firmware - I recently sold a main board to a user on here to fix similar fault, but these main boards are hard to come across...
- bad power supply: shorted diode on 17PW25, 17PW26 PSUs, or bad FAN-chip on primary, or open circuit sense resistors+other blown parts.

[andrasin]

Re: LCD TV SHARP LC-32SH340E can't start

I can't find any schema of this PSU. Do you have any? It's 17PW82-2 v.1 090511.

Some people told me that i should check CCFL backlight by entering service mode, where should be record of errors. But I can't enter it. Tv does not response.

[tom66]

Re: LCD TV SHARP LC-32SH340E can't start

17PW82 ah OK it's a slightly newer PSU but very similar to 17PW26 so you can try with that schematic instead.
http://www.tgohome.com/ServiceManual...&Search=Submit

Just check if you have 5V, 12V and/or 24V out from PSU. 24V is easiest to check at inverter connection.

Inverter fault is for older Sharp actually made by Sharp, these Vestel sets do not detect an inverter fault and will power on blindly (no backlight / backlight flickers on.) You have a protection fault, indicated by a slow blinking LED.

[andrasin]

Re: LCD TV SHARP LC-32SH340E can't start

OK i have 12V, 3,3V 24V but there is no 5V. On 3 pins where should be 5V i got 0,8V only.

[tom66]

Re: LCD TV SHARP LC-32SH340E can't start

Post a picture of the underside of your power supply. The 5V is generated by buck converter from 12V supply.

[andrasin]

Re: LCD TV SHARP LC-32SH340E can't start

Sorry for bad quality, not easy in night

I found brown place right under IC803 (MDS5852), it's on photo, looks like it was overheated.

[tom66]

Re: LCD TV SHARP LC-32SH340E can't start

Can you double check that part #? Can't find anything on it. It is quite possible that part is at fault.

[andrasin]

Re: LCD TV SHARP LC-32SH340E can't start

Sorry for that, MDS 5652 DK 174HGG

[tom66]

Re: LCD TV SHARP LC-32SH340E can't start

OK, that's the MOSFET, it could be bad and can be tested later. What about IC801?

[andrasin]

Re: LCD TV SHARP LC-32SH340E can't start

I never tested Optocoupler before. How can I do it? There is LED at pin 1 and 2, I tested it with digital multimeter in diode test mode and diode is OK. But what next...

[tom66]

Re: LCD TV SHARP LC-32SH340E can't start

Uhh.. sorry, my error. I meant to say IC800 or IC808, directly below IC803 (hard to see exact ref des.)

[andrasin]

Re: LCD TV SHARP LC-32SH340E can't start

This is 1579 Low Voltage Synchronous Buck Controller. I will test it but I'm not sure how, I'm still beginner.

[matyka]

Re: LCD TV SHARP LC-32SH340E can't start

Hello,I have a similar problem with the power supply 17pw82-2
Could someone please help me to trace down the fault not having the 12v on connector PL816 pin 1,3,5,7,9 should have 12v

[michael dranfield]

Re: LCD TV SHARP LC-32SH340E can't start

Hi, Everyone , here is the Vestel 17PW82-2 schematic.