Olevia 342-B11 PSU problem, No voltage in secondary PSU

[Robbiebaby]

Hey guys! let me first say that this place is awesome, and it's helped me alot so far. Thanks guys!!! This is my first thread (I posted about a different problem/solution I had in a different thread) But I have a new problem that I can't seem to figure out.

So it goes like this, I have an Olevia 342-B11 42" LCD which I got from someone a while ago, Apparently what happened was that their power went out, and then when the power came back, they turned the TV on, or something along those lines, but heard a loud pop, and after that it wouldnt turn on at all. No standby, no lights, no nothing. Well I got it from them, I opened it up, and examined the power board. One of the MOSFETs had its middle leg blown off (It literally looked melted off) While the right leg was just a bit scorched, but when I desoldered it, it fell off. The left leg is OK, You can actually see it in the picture, I put it next to its replacement, which is the exact same model #04N70BF (which was really hard to find, but I got lucky on ebay). Right infront of the mosfet was a 100pF 1kv capacitor, which I think might have had the explosive charred soot on it from the mosfet, but I wasnt sure, so I replaced it too. But I replaced it with a ceramic one with the same parameters.... I dont know If I should have found an identical blue one that all the other ones on the board are.

The Power Board Model is FSP271-4F02

But either way. I thought that would have fixed the problem. But it still wouldn't turn on. The only voltages I get range from 58.1-59.7 all across the Primary area of the power board. None of the voltage gets through to the secondary part. The secondary is completely voltageless (if thats a word :-P)

I get readings of 58.1-59.7 at all the leads of IC 4 5 6 and 7 on the primary side, but 0 on secondary side.
I get 59.4 on the blue capacitor BS2 on the primary, but none on the other side.
On the small transformer I get 62.2 on each lead on the primary, but nothing on the other side.
On the larger one, there is no voltage on either lead in either side.

Now obviously this PSU still has the crappy CapXCon capacitors on it...Which I should replace, But I dont think they're a problem at this moment

So well...I dont know whats wrong with it....Maybe you guys can help?

Let me know if you need anymore information, I posted the pictured of both sides of the PSU, the control board and the replaced Capacitor and fet in its proper place.

I shopped around, the cheapest replacement is $65 with free shipping.

Thanks for the input in advance!

[PlainBill]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

This is a standard design for a TV power supply. There is a standby supply, on whenever AC power is applied to the board, a main supply that is controlled by the main board, and a PFC front end. The voltage you reported is very unusual, hopefully this is due to a technician error. The pictures are very helpful.

1. What is the voltage across the legs of the large cap (C1)? This should be 1.4 x your line voltage - about 165 volts in the US and Canada

2. What is the part number for IC2?

PlainBill

[Robbiebaby]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

I hope it is the technicians error :-P

C1's voltage is 153.7

IC2 says:
230D6 (or 23006)
PLH5 (or PLHS)

[PlainBill]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

I hope it is the technicians error :-P

C1's voltage is 153.7

IC2 says:
230D6 (or 23006)
PLH5 (or PLHS)

The voltage across C1 seems a little low. What is the AC voltage on the input to the power supply?

Googling 230D6 leads to NCP1230D65R2, a standby SMPS controller. Is pin 4 of IC2 connected to the negative lead of the large cap? And is pin 5 linked to the FET that blew?

PlainBill

[Robbiebaby]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

Input voltage is 122v AC, Is there maybe a different way of checking the voltage on the cap? I checked with the + to + and - to - on the cap with the multimeter.

Pin 4 of IC2 is connected to both the large cap's negative lead, and the FET's Right lead. Pin 5 doesn't get any continuity between either of the components. Or am I checking it wrong?

Also if anything, the Positive lead of the cap is connected to the middle lead of the FET.

[PlainBill]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

Input voltage is 122v AC, Is there maybe a different way of checking the voltage on the cap? I checked with the + to + and - to - on the cap with the multimeter.

Pin 4 of IC2 is connected to both the large cap's negative lead, and the FET's Right lead. Pin 5 doesn't get any continuity between either of the components. Or am I checking it wrong?

Also if anything, the Positive lead of the cap is connected to the middle lead of the FET.

122 VAC should give about 169 VDC across the large cap. I don't think we are dealing with technician error here, and the discrepancy may be significant. I'd try measuring the AC voltage at the center pins of the bridge rectifier. Also, what brand of DMM do you have?

You are probably checking for connectivity wrong. It's not a direct connection - there are often several components involved to shape and limit the drive pulse.

However, at least superficially the IC does seem to match a NCP1230D65R2. My tentative working theory is that IC2 got zapped when the FET shorted, so let's try some more measurements. What are the voltages on the other pins of IC2?

Something else you should consider. A quick check did not find any source for the NCP1230D65R2. While both DigiKey and Mouser list it, it's not in stock, the minimum order is 2500, and Mouser indicates no lead free version is available. A number of sites in China indicate they have them, but that is not necessarily a reliable indication.

Whoops!!! Correction - Google is your friend. There is an eBay seller who has them, and they are in the US. Strange that searching on eBay directly doesn't find the auction.

PlainBill

[Robbiebaby]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

The voltage at the rectifier pins is 122 in one of the center ones. Then, going left from the 122v pin I have 58.8 in the next, and then 61.8 at the last pin, there is no AC voltage at the pin on the right side of 122. but there is -59.5

Im using a Cen-Tech DMM model which is a rebranded mastech, but I think its all the same thing. I also have an elenco and a radio shack one, and they all read the same voltages at the areas that I mentioned in previous posts.

When I was checking continuity with pin 5 and the FET, It does have continuity with pretty much everything pin 4 has. It also does look to be connected to the FET's left pin, but only after going through a resistor or two. It also has continuity with the right pin all the time.
On further testing, I noticed that occasionally pin 5 would have continuity with the middle pin on the FET but only momentarily. Then it wouldn't have any until I traced the tested on another area with different pins. I couldn't recreate this phenomenon consistently, but I wasn't able to get pin 4 to do the same thing. But maybe it does too.

The voltages at the other pins on IC2:
Pin1: -57.2v
Pin2: -58.1v
Pin3: -59.6v
Pin4: -59.6v
Pin5: -59.7v
Pin6: -57.4v
Pin7: not connected
Pin8: +27.0v

Also I would like to say that the voltages I mentioned in the first post at IC4,5,6,7 were all negative. I forgot the - sign whoops.

One more thing. You say you found a seller in the US for the IC on ebay. I looked on Google/ebay, but was only able to find listings that already ended. I did find one from a China seller, though it cost $10 with shipping :-|

[PlainBill]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

The voltage at the rectifier pins is 122 in one of the center ones. Then, going left from the 122v pin I have 58.8 in the next, and then 61.8 at the last pin, there is no AC voltage at the pin on the right side of 122. but there is -59.5

Im using a Cen-Tech DMM model which is a rebranded mastech, but I think its all the same thing. I also have an elenco and a radio shack one, and they all read the same voltages at the areas that I mentioned in previous posts.

When I was checking continuity with pin 5 and the FET, It does have continuity with pretty much everything pin 4 has. It also does look to be connected to the FET's left pin, but only after going through a resistor or two. It also has continuity with the right pin all the time.
On further testing, I noticed that occasionally pin 5 would have continuity with the middle pin on the FET but only momentarily. Then it wouldn't have any until I traced the tested on another area with different pins. I couldn't recreate this phenomenon consistently, but I wasn't able to get pin 4 to do the same thing. But maybe it does too.

The voltages at the other pins on IC2:
Pin1: -57.2v
Pin2: -58.1v
Pin3: -59.6v
Pin4: -59.6v
Pin5: -59.7v
Pin6: -57.4v
Pin7: not connected
Pin8: +27.0v

Also I would like to say that the voltages I mentioned in the first post at IC4,5,6,7 were all negative. I forgot the - sign whoops.

One more thing. You say you found a seller in the US for the IC on ebay. I looked on Google/ebay, but was only able to find listings that already ended. I did find one from a China seller, though it cost $10 with shipping :-|

Wow!!! Quite a few points to cover.

When dealing with a SMPS, you must be aware of the difference between the hot side and the cold side of the board. In simplest terms, the ground point for everything between the bridge rectifier and the SMPS transformer is at an elevated AC potential with respect to earth ground. All measurements on the SMPS controller must either pin 4 of IC2 or the negative lead of the large cap.

Something very strange is going on with eBay; I'm not sure if it is at my end, eBay, or related to the phase of the moon. Auction 200372683818 is for one 230D6 IC, which the seller also lists as a NCP1230D60. Perhaps you can compare the picture in the auction to the IC you have.

PlainBill

[Robbiebaby]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

Oh wow, I was going about this all wrong O.o I was using the ground as the negative the whole time.
Thanks for the correction, the new measurements with pin 4 as the negative are as follows:

Pin1: 2.791v
Pin2: 1.787v
Pin3: nothing
Pin4: nothing
Pin5: nothing
Pin6: 2.783v
Pin7: not connected
pin8: 109.7v


Also on ebay, I got it now...but It didn't show up for me before...weird. Thanks, yes that's the same one I have except the letters on mine are PLHS.

[PlainBill]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

Oh wow, I was going about this all wrong O.o I was using the ground as the negative the whole time.
Thanks for the correction, the new measurements with pin 4 as the negative are as follows:

Pin1: 2.791v
Pin2: 1.787v
Pin3: nothing
Pin4: nothing
Pin5: nothing
Pin6: 2.783v
Pin7: not connected
pin8: 109.7v


Also on ebay, I got it now...but It didn't show up for me before...weird. Thanks, yes that's the same one I have except the letters on mine are PLHS.

The key here is pin 6 - Vcc. Vcc is generated internally, drawing power from pin 8. At this point I'd say it's time to replace IC2.

PlainBill

[Robbiebaby]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

I'll order one, but I think I found it on mouser. Is NCP1203D60 the same as NCP1203D60R2G? The R3G is in stock at mouser for 1.14 each.

Also, could anything else be broken on the board? or would we have to wait for IC2 to check? I realize this is a silly question to ask, as obviously the whole board could be fried, but just wondering what else might be a problem if IC2 doesn't work.

[PlainBill]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

I'll order one, but I think I found it on mouser. Is NCP1203D60 the same as NCP1203D60R2G? The R3G is in stock at mouser for 1.14 each.

Also, could anything else be broken on the board? or would we have to wait for IC2 to check? I realize this is a silly question to ask, as obviously the whole board could be fried, but just wondering what else might be a problem if IC2 doesn't work.

You'll have to look at the datasheet to be sure. Make sure it's the same package. Pinout is important!!

I would carefully check the components between pin 5 of the SMPS controller and the gate of the FET. Also, check to make sure the output diodes aren't shorted.

PlainBill

[Robbiebaby]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

Thanks alot, But I got a silly question....Which ones are the output diodes? :-)

[PlainBill]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

Thanks alot, But I got a silly question....Which ones are the output diodes? :-)

"The only silly question is the one that isn't asked". OK, that's not true. Art Linkletter asked his wife "Are you sure you want to go through with this?" as she was going to the delivery room. THAT was a stupid question.

The items circled in yellow are the diodes on the secondary. I think the one circled in orange is a voltage regulator. Check the diodes by checking for shorts from the center pin to the other two pins.

PlainBill

[Robbiebaby]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

I checked the diodes, I think theyre ok....I think....

But either way thanks for your help. I will order the IC and will keep you posted. I will update this once it comes in.

[cashkennedy]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

I have a 42" olevia that uses the same power supply (fsp271-4f02) although its a different model.

When I bought it to fix it had a blown main ac fuse which I replaced and it instantly blew when I reconnected the power. According to fixya this is probably a transistor in the primary section of the board which I tend to believe since all the caps look perfect (very rare for capxcons). What kind of reading should I take to isolate the bad transistor. I'm guessing the IC he has been probing is the one in the middle on the back side of the board and I should use pin 4 as the negative... But with the fuse blowing instantly this is impossible. Should I be looking for continuity from both outer leads of a transistor to indicate a short? (Totally guessing here).

[PlainBill]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

I have a 42" olevia that uses the same power supply (fsp271-4f02) although its a different model.

When I bought it to fix it had a blown main ac fuse which I replaced and it instantly blew when I reconnected the power. According to fixya this is probably a transistor in the primary section of the board which I tend to believe since all the caps look perfect (very rare for capxcons). What kind of reading should I take to isolate the bad transistor. I'm guessing the IC he has been probing is the one in the middle on the back side of the board and I should use pin 4 as the negative... But with the fuse blowing instantly this is impossible. Should I be looking for continuity from both outer leads of a transistor to indicate a short? (Totally guessing here).

This sort of problem should be walked through carefully. Yes, a shorted FET will blow the fuse instantly. A shorted bridge rectifier will do the same.

I prefer a two step approach to testing these components. Let's start with the bridge rectifier. Number the leads 1 - 4. Obviously, if you start at one end it is easier. Set your DMM to the 200 ohm range.

Now measure the resistance between the following pins:
1-2, 1-3, 1-4, 2-3, 2-4, 3-4
All should read greater than 200 ohms. If any read less, the component is bad, replace it.

Now set your DMM to the diode test range. For this test, hold the black probe on the first pin number, the red on the second.
1-2, 1-3, 1-4, 2-3, 2-4, 3-4, 2-1, 3-1, 4-1, 3-2, 4-2, 4-3
Interpreting these is a little trickier. No pairs of pins should show a reading in both directions. Some may show no reading in either direction.

For the transistor, do the same, but of course there will be no pin 4.

PlainBill

[cashkennedy]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

When i earlier asked about testing the transistors i meant the MOSFETs. After finding this article i reinspected my MOSFET's and the same one that the OP had problems with has a little bit of melting on the circled pin on the board that has the extra diode on the lead.

Now i dont want to just replace that if anything else is bad so i did all the other measurements you requested.

For the bridge rec (which i assume is the 4 pin item also thermal pasted to the aluminum heatsinks) the markings are pec (brand) 704v RU (symbol) then over pin 1 and 2 is KBU and over pins 3 and 4 is 8J . Additionally Pin 1 is marked ( - ) , pin 2 is marked ( ~ ), pin 3 is marked ( ~ ), and pin 4 is marked ( + ).

For the 200 resistance measurement across each pin i get the following
this is while im testing it in circuit / still on the board
~ means i get a instaneous resistance reading but it goes away
--- is obviously ones you cant test (pin 1 with pin 1)

positive lead on pin
```1```2```3````4
1``--``~```~```6o
2``~``---``~```~
3``~```~``---``~
4``6o``~```~``---
^neg lead on pin

So pin 4 and 1 seem to be continuous

For the diode measurement (also still on the board / in circuit)

positive lead on pin
``1````2````3````4
1 --- `.562 `.583 .000
2 .575 `--- 1.434 .575
3 .578 1.410 `--- .578
4 .000 `.561 `.582 ---
^ neg lead on pin



For the MOSFET that is labeled Q5 and is the same one as the other guy replaced.

resistance readings (still on board/ in circuit)
x means there was no instant resistance it just was too high resistance to read/ or not continuous.

positive lead on pin
``1```2```3
1 --- `x` `x`
2 `~` --- `~`
3 `~` `~` ---
^neg lead on pin

For the diode measurement (also still on the board / in circuit)

positive lead on pin
``1 ```2 ``` 3
1 `--- `x` `~`
2 .451 --- `x`
3 .814 `x` ---
^neg lead on pin

(Obviously I havent unsoldered anything but I can do so if necessary, not sure if that affects readings on these parts.)

Thank you for your very quick reply.

[cashkennedy]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

And now i know why no one uses tables on this forum! lol hopefully you can read them now that i added ` for spaces ... just ignore all the apostrophes

[PlainBill]

Re: Olevia 342-B11 PSU problem, No voltage in secondary PSU

The diode bridge appears to be good, but something is shorted on the main output.

PlainBill