MP 42HC56 SINOTEC 42 lcd

[battlecat]

Good evening all.
Anyone came across this this PSU board ?
No bad caps (wow) but dead.

all switch mode transistors test 100%
had 1 dogey cap .
and it is not powering up , not even the separate psu on the board that from tracing seem to be the standby psu which in turn switch on the rest of the main board.

i have my suspicions on ic :n501 (Q110 wich is a FPS chip from fairchild semi)
ordered and waiting from RS components..

BUT would like some thoughts around it..

[budm]

Re: MP 42HC56 SINOTEC 42 lcd

What DCV do you get between the two legs of the main filter cap in the primary side?
BTW, so no DCV on any one of the connector in the secondary side of the circuit at all?

[battlecat]

Re: MP 42HC56 SINOTEC 42 lcd

Hi

320v dc it's actualy have 2 filter caps,

one for the 24v supply and a 2nd for the standby..

i have attached a bottom pcb view..

I highly suspect that fps ic

[CapLeaker]

Re: MP 42HC56 SINOTEC 42 lcd

Sounds like your PFC isn't working

[budm]

Re: MP 42HC56 SINOTEC 42 lcd

Hi

320v dc it's actualy have 2 filter caps,

one for the 24v supply and a 2nd for the standby..

i have attached a bottom pcb view..

I highly suspect that fps ic

Only one filter cap C533 220uf 450vdc.
VPFC is used for running the 24V and the standby power supply, when in standby mode, the standby power supply will run on 330VDC (no boosted Voltage yet until PS-ON is present from the main board).
What DCV do you have on IC N501 VCC pin 2 and GND pin 1? C513 is the startup/running cap for the IC N501.
The PFC and the 24V will not function until the STANDBY power supply section works first.

[CapLeaker]

Re: MP 42HC56 SINOTEC 42 lcd

Sorry... I thought PSon is there, but 320V on the filter caps (240V rectified) = no PFC

[battlecat]

Re: MP 42HC56 SINOTEC 42 lcd

OK so here is a bummer the FSQ110 from Fairchild is discontinued ...grrrrr...
Had a look at their datasheets ""with my extremely slow internet connection""

Followed the ""rabbit "" and pointed me to the FSL206MR which I ordered via RS-Online... and seem there is a couple of light mods needed to get this chap working in there...

Seem I don't get any voltage on pin 1 and 2 like BUDM mentioned .. not even with the FSL206 in place ...pin 5 is the point to which the cap at pin 2 and 1 get charged up to switch on the Ic N501.. ( maybe some experimenting with the resistor values at pin 5)

Would it be possible if someone could maybe check up on the FSQ110 versus the FSL206 if I made the right choice there?

Thanks for the advice and replies thus far

[battlecat]

Re: MP 42HC56 SINOTEC 42 lcd

HERE is the really bad news .....




No idea how did manufacturers still went ahead and use these devices if this was happening

[SonOfAnarchy ZA]

Re: MP 42HC56 SINOTEC 42 lcd

Hi guys. Sorry to revive this old thread I''ve also got the same supply and it died as well. blown fuse and D506 was dead short everything else seems to measure correctly I cant seem to find that specific diode but put in a fast recovery diode with similar specifications but the supply is still stone dead I suspect N507 (l6563) to be faulty but not sure was the problem ever resolved on this fault?

[SonOfAnarchy ZA]

Re: MP 42HC56 SINOTEC 42 lcd

I have 7vDC on N105

[SonOfAnarchy ZA]

Re: MP 42HC56 SINOTEC 42 lcd

and 280vDC across the two filter caps

[battlecat]

Re: MP 42HC56 SINOTEC 42 lcd

Hi , check the small electrolyitic cap next to the N105... sit close to pin 1

DON"t even check it just replace it.. with exactly the same value.. anything higher or lower messed me around..

That will switch on the chip.

Also watch out for the HT boards on this tv Master & Slave...


FSL206MR that I bought was actually totally wrong

[SonOfAnarchy ZA]

Re: MP 42HC56 SINOTEC 42 lcd

Hi , check the small electrolyitic cap next to the N105... sit close to pin 1

DON"t even check it just replace it.. with exactly the same value.. anything higher or lower messed me around..

That will switch on the chip.

Also watch out for the HT boards on this tv Master & Slave...


FSL206MR that I bought was actually totally wrong

I replaced that cap with no luck. i found a 16v zener diode in short (D502) replaced it but no luck is it possible N501 is faulty?

[battlecat]

Re: MP 42HC56 SINOTEC 42 lcd

Is this Power supply the exact same one as posted in the picture of my thread?

Having blown zeners sounds more that this TV had a direct lightning strike.

I have been unsuccessful to source the correct chip located at N501 and only found similar ones that works but not in the way intended , hence my discovery of the cap that caused it to not switch on..
My last resort was to build a power supply, to supply power the other 2 that this 1 starts up..

FSQ110 versus the( FSL206 this particular chip works in a pulse mode effect) RS is closer to you as you are in JHB.. order this and try it in the old N501's place.. At least it would give you a good idea what to look for.....as it does work without any mods.

Otherwise suppliers they still have stock of this TV's PSU and CFL driver boards checked 2 months ago..

[SonOfAnarchy ZA]

Re: MP 42HC56 SINOTEC 42 lcd

Yes it is the exact power supply. i Have ordered that specific chip from China will let you know if it works out

[SonOfAnarchy ZA]

Re: MP 42HC56 SINOTEC 42 lcd

Is this Power supply the exact same one as posted in the picture of my thread?

Having blown zeners sounds more that this TV had a direct lightning strike.

I have been unsuccessful to source the correct chip located at N501 and only found similar ones that works but not in the way intended , hence my discovery of the cap that caused it to not switch on..
My last resort was to build a power supply, to supply power the other 2 that this 1 starts up..

FSQ110 versus the( FSL206 this particular chip works in a pulse mode effect) RS is closer to you as you are in JHB.. order this and try it in the old N501's place.. At least it would give you a good idea what to look for.....as it does work without any mods.

Otherwise suppliers they still have stock of this TV's PSU and CFL driver boards checked 2 months ago..

which supplier did you contact? i have received the correct parts with no luck still dead as a door knob

[kc8adu]

Re: MP 42HC56 SINOTEC 42 lcd

check r597 r598.
thats your startup source.
what voltage do you have pin 2 and 5 of n501?

[SonOfAnarchy ZA]

Re: MP 42HC56 SINOTEC 42 lcd

check r597 r598.
thats your startup source.
what voltage do you have pin 2 and 5 of n501?

Pin 2 Has 10VDC
Pin 5 Has 184VDC

R597 and R598 measure 68kOhm according to the circuit diagram they should be 47KOhm

[dick_barton]

Re: MP 42HC56 SINOTEC 42 lcd

I replaced that cap with no luck. i found a 16v zener diode in short (D502) replaced it but no luck is it possible N501 is faulty?

If D502 had gone short then the Opto N506 may also have been damaged. I would certainly check it.

What DC voltage do you have on D505.

[SonOfAnarchy ZA]

Re: MP 42HC56 SINOTEC 42 lcd

If D502 had gone short then the Opto N506 may also have been damaged. I would certainly check it.

What DC voltage do you have on D505.

2vDC anode
0v cathode

n506 has been replaced