Philips 230WP7NS Professional Series LCD

[Scenic]

Got one of these for next to nothing. Previous owner said he got it from a friend and after a couple months it just didn't turn on anymore (completely dead).

PSU board is shot. What I've been able to diagnose so far:

- one primary side MOSFET is completely shorted (0 ohms on all pins)
- the other primary side MOSFET is completely open
- 1 resistor close to them "exploded" (lost part of the outer casing)
- another resistor below the above one is shorted (and was covered in soot)
- 4 amp mains fuse is open

Apart from one tiny Capxon (what else), none of the caps are bulging, even though they're all junk brands (Capxon KF/KM and Elite EB/PF). I expected much better from a monitor that retailed for 900 USD or more when it was new..

I'm not very experienced when it comes to fixing up the primary side of power supplies, so I kinda need help here. In a scenario like this, are there other components that are likely to be bad? If so, which parts would that be?
I'm suspecting the SMPS controller IC (Philips/NXP TEA1507P) could be damaged as well, but I don't know for sure (and much less how to test it in this situation).

As this is a 23" 1920x1200 LCD monitor with a S-IPS panel, I wouldn't mind spending a couple more bucks on fixing it than usual.

One thing that annoys me a bit is that the pin headers (to the inverter and the mainboard) aren't labeled at all apart from the pin count, so I'll have to look at the SM all the time..
Talking about service manuals.. I managed to find a sort of incomplete one. The PSU diagram is there but the PCB shot is useless as it's a regular image (think JPG), not a vector graphic. When will people learn to create proper PDFs!?

"Servicemanual" (almost 13MB)
https://cdn.badcaps-static.com/pdfs/...0af21ab69b.pdf

PSU board diagram is on page 10, the almost useless PCB shot on page 11 (blurry mess)

There are a few inconsistencies between the PDF and what's on my PSU board though, which doesn't make this any easier I think.

The completely shorted MOSFET is marked 7135 on the PCB (and in the manual), and is a ST P10NK80ZFP (800V, 0.78ohm, 9A), whereas in the manual it's a P7NK80ZFP (800V, 1.5ohm, 5.2A)
The open one is marked 7113 on the PCB and is a ST P20NM60 (matches the manual).

More inconsistencies with the resistors next to them. The one that "blew up" was still readable, and said 0.22 ohm. It's marked 3139 on the PCB. The manual however says that's supposed to be a 0.15 ohm (1W 1%) resistor.
The other resistor below that one (marked 3115 on the PCB) was covered in soot from it's blown up brother, and my attempt at cleaning proved to be a little bit too effective, as I wiped the markings off as well
According to the manual that's also supposed to be 0.15 ohm (1W 1%)

The SMPS controller IC, which might or might not be damaged due to the blown-up parts is a Philips/NXP TEA1517P.

I've attached all the datasheets to this post, as well as a bunch of photos from before desoldering parts to check them out of circuit.
Sorry for the bad solder-side photos.. the huge ground traces with solder on them didn't really help with their reflections. I'll try to take some better ones later

So.. what do you suggest checking apart from the bad parts I already found? Should I just go ahead and order the parts as per the manual and hope it doesn't end in fireworks..?

[retiredcaps]

Re: Philips 230WP7NS Professional Series LCD

I'm not very experienced when it comes to fixing up the primary side of power supplies, so I kinda need help here. In a scenario like this, are there other components that are likely to be bad? If so, which parts would that be?

I would check the bridge rectifier for shorts even though it might be okay.

I'm suspecting the SMPS controller IC (Philips/NXP TEA1507P) could be damaged as well, but I don't know for sure (and much less how to test it in this situation).

Try a resistance test between GND (pin 2) and every other pin. That is, 1-2, 3-2, 4-2, 5-2, 6-2, 7-2, and 8-2.

So.. what do you suggest checking apart from the bad parts I already found?

I would test all the diodes to see if any are shorted.

[Scenic]

Re: Philips 230WP7NS Professional Series LCD

Thanks for the reply

The bridge rectifier (GBU6J ; 6A) tested OK. I'll check the TEA1517P and the diodes near the MOSFET graveyard tomorr..err.. today, as it's 12:30 AM here right now. I already found a little general purpose SMD diode (PCB marking 6138 ; a "BAV103") on the solder side of the PCB across the blown up resistor to be open when testing around earlier.

RS-Components seems to have both MOSFETs and the SMPS controller in stock, so I guess I'll buy from there (free shipping and no need to worry about china fakes )

The only thing that still puzzles me are the two resistors (0.15ohm in the manual vs. 0.22ohm on the actual board..)

[budm]

Re: Philips 230WP7NS Professional Series LCD

If they use 0.22 Ohms instead of 0.15 Ohms for the MOSFETs Source resistor, it means that the over current trip point is lower when use higher resistance since it will take less current to develop voltage on the higher Ohm resistor for the Over current feedback to the SMPS IC PIN, thus it will shutdown at lower over current trip point than the one that use the 0.15 Ohm resistor.
And one thing when MOSFET shorted out, it may have taken out the output drive circuits of the SMPS IC, the Diode and resistors that are connected to the Gtae of the MOSFET'S with it also.
From the look of the board, it does not have standby power supply that I can see, it does have PFC circuits. And yes, those resistors are for the Source resistors, one (3115) for the PFC MOSFET, one (3139) for the main power supply MOSFET.

[retiredcaps]

Re: Philips 230WP7NS Professional Series LCD

Oh yeah, try the light bulb trick after installing new components unless you have a variac.

https://www.badcaps.net/forum/showpo...07&postcount=7

[Scenic]

Re: Philips 230WP7NS Professional Series LCD

Allrighty.. Checked all the diodes I could find on the primary side. Found a few bad ones along with a few resistors (see attached pic.. stuff in the red boxes is bad)
I also tried to mark the same parts on the actual photo of the backside of the PCB. Hopefully not too much of a mess to follow..

I'm getting some readings on the SMPS controller IC and no pin appears to be shorted to ground. Good sign I guess. Same goes for the PFC controller IC (ST L6562N).

I also noticed that I used the wrong model number for the SMPS controller IC throughout all my previous posts. It's a TEA1507P, not TEA1517P as I wrote before for whatever reason

I'll go ahead and order the parts from RS, including the SMPS and PFC controller ICs (just in case.. both ICs combined cost less than each of the MOSFETs..)

Also thanks for the lightbulb trick tip. I've already used that multiple times before.
Crude but effective

edit: Seems like I'll have to get the resistors (0.22/0.15ohm) elsewhere, as RS doesn't seem to have any 1+W 1% ones with those values

[budm]

Re: Philips 230WP7NS Professional Series LCD

Hi scenic, is RS = Radio Shack in UK?
By the way, when I check the IC, I check all other pins to ground pin and also all the pins to VCC pin.
keep us up to date.

[Scenic]

Re: Philips 230WP7NS Professional Series LCD

By RS I meant RS Components (a.k.a. Allied Electronics in the US)
There's no such thing as RadioShack over here, although there seems to be a company with similar business practices called "Conrad Electronic" (conrad.de or .com) over here, which mostly sells cheap junk, and the few useful things/parts they have are usually ridiculously overpriced (think: two resistors for 1eur (1.30usd) in their retail stores and stuff like that..)

[Scenic]

Re: Philips 230WP7NS Professional Series LCD

Okay.. forget about RS Components. Turns out they only sell to resellers and businesses

Great.. now my options are down to ebay (and potentially fake parts from China/Hong Kong) or local electronics stores which are almost guaranteed to be more expensive.
Digikey isn't an option because of the shipping costs. (18EUR (23.30USD) unless you order more than 65eur (84USD!) worth of parts).
All other (local) online electronics stores that I know of don't seem to have any of the parts..

Frustration is quite an understatement..

[budm]

Re: Philips 230WP7NS Professional Series LCD

I have to say, we are so lucky here in the US when it comes to getting parts. I would think UK, Germany will have easy access to parts easily, that makes it hard for DIY people.

[retiredcaps]

Re: Philips 230WP7NS Professional Series LCD

I have to say, we are so lucky here in the US when it comes to getting parts.

Absolutely with digikey's low cost first class mail price of $2.75ish and usually 48 to 72 hour delivery.

You guys are also lucky with ebay as well. I can only imagine how many more multimeters (especially being opportunistic with BIN pricing) I would have if sellers shipped to Canada for the same low $5 to $6 as the USA.

I use ebay and get parts from China and usually wait 4 to 7 weeks. That is part of the reason why my repairs take so long. The local electronics store prices things like there is no competition, ignore USA/CDN $ parity, and are oblivious to something called the Internet. I won't support the local people when their prices are 100 to 200% higher (or more) for the exact same item.

[Scenic]

Re: Philips 230WP7NS Professional Series LCD

Allright.. after searching around a bit, I found out that Farnell/Element14 has most of the parts in stock, with the exception of the TEA1507P SMPS controller and the L6562N PFC controller
(they do have the L6562P, but that's the SMD (SOIC8) version)
Shipping costs also aren't too bad at 7.95eur (about 10usd) for orders of less than 50eur/65usd.

By the way... those conformal coated 0.15ohm 1W 1% resistors are pretty damn expensive .. 1.52eur (almost 2usd) a piece

Let's hope the SMPS and PFC controller ICs are OK and the replacement parts don't go up in smoke on the first try.. The lightbulb trick should prevent that from happening, but you never know..

[budm]

Re: Philips 230WP7NS Professional Series LCD

@retiredcaps, boy that does not make sense when Canada is just right across the border with a lot of Hi-Tech companies. I hate to find out how much local shops charges for repair, but at the same time I was told Canada has better and cheaper health care system.

[Scenic]

Re: Philips 230WP7NS Professional Series LCD

oh eff this.. farnell also sells to businesses only.. and they only tell you that after searching your ass off comparing parts and specs, puting all your shit in the cart and registering an account. Needs a business address. GREAT

I'm pissed enough to bin this monitor right now >.<

If I go the ebay route I'll have a problem too. No conformal coated resistors in the needed values (just regular ones from china), the MOSFETs would come from malaysia (of all places) or hong kong (possibly relabeled fakes) and forget about getting matching SMD parts (resistors, diodes) for reasonable prices or in "human" quantities (less than 500)..

It's 6:15 AM and I haven't slept yet but I'm gonna drive to the electronics store later to see what they can do. Last hope.

Time for lots of coffee and loud music to keep me up for another hour

[imp]

Re: Philips 230WP7NS Professional Series LCD

Scenic, have you tried https://www.distrelec.de/home ? They´re called ELFA in Sweden and sells to non businesses as well.

[Scenic]

Re: Philips 230WP7NS Professional Series LCD

Haven't heard of that shop before, but sadly they don't have either of the MOSFETs (which are the most important / "hard to get" parts)

Solved it already though. Went to the electronics store which didn't really have most of the parts.. mentioned the RS and Farnell disaster and got a tip from that guy about a Farnell-reseller called "HBE" (hbe-shop.de) which sells to private persons as well.
The shop UI sucks balls (the description is just one giant blob of text instead of the neat spec-chart on Farnell and there's no search result filtering), but the cool thing is that you can just paste Farnell order codes (like "9512756" for the STP10NK80Z) into their search and you get the identical part as you would on Farnell
So all in all it was just a matter of a lot of copypasta of those order codes from my Farnell cart to HBE. Stuff is already on the way

[imp]

Re: Philips 230WP7NS Professional Series LCD

Amazing! Glad you finally could order the parts Scenic

[retiredcaps]

Re: Philips 230WP7NS Professional Series LCD

@retiredcaps, boy that does not make sense when Canada is just right across the border with a lot of Hi-Tech companies

Sorry for going off track on this thread ...

From cars to books, Canadians pay more for everything

http://ca.news.yahoo.com/blogs/daily...163054422.html

[tom66]

Re: Philips 230WP7NS Professional Series LCD

If that Capxon that bulged was for the Vcc for the controller IC, it could have caused the controller to go a little crazy (for example, keeping the gate high due to latch up) and damage the MOSFETs.

[Rtech]

Re: Philips 230WP7NS Professional Series LCD

I have 'cash with order' accounts with both RS and Farnell in the UK,and I am not a Business,but do these repairs etc, just to stop me from going senile(old age is a swine),the only requirement is that there has to be a minimum order vale of £20.
Good luck with your repair.