Needs caps for my 22" lcd

[Nicks84]

Re: Needs caps for my 22" lcd

Ok, pulled them out. Talking about a board crisis.

The 1st one came out with very little issues. Well, that is, one pad came off. Seemed the original solder just gummed up and didn't seem to want to wicked or sucked up. I did add fresh solder and all of it came off, except the fraction that was gummed :-? I could not seem to get it to merge. Anywho, the pad came off on a couple, and then like 1/2 way on a couple

The 2nd one, seems all the legs were like that. But no pads came off completely, but they are all compromised and there is still solder that wont seem to come off. I did try wicking it after using the wick. That FET clung on for dear life, it did not want to come out for nothing. I fear for the integrity of the board now (solder pads). My instructors in College would be heavily disappointed.

In anycase, the good news is that when pulled out, both FETs measured exactly the same as in my previous post. So it looks like I need to order some of these, as these are def shorted. Anything else I can do for now, or not until I replace the parts ?

[Nicks84]

Re: Needs caps for my 22" lcd

Also, I forgot to ask. Is there a certain brand I want to stay away from (or get, rather)?

[steve2]

Re: Needs caps for my 22" lcd

http://cgi.ebay.com/LOT-TWO-2-AOP605...item562fa74164 Well, at least you only have to fix one pad. There is cheaper ones on ebay, but if you click US only , it list 4 items. Too bad digikey is out of them as they are 87 cents there.

[Nicks84]

Re: Needs caps for my 22" lcd

Ok, so I ordered the MOSFETS, and they came in today
BUT, they measure the exact same as the ones that were suspected to be shorted Could it be possible I measured them wrong?

I referenced the pins according to the drawing, dot and notch at the bottom as shown in the drawing. I used the data sheet found here:


I referenced this also:

See post 13, point #2 athttps://www.badcaps.net/forum/showthread.php?t=10419

In anycase, It still does the same thing even after installation of the new MOSFETS (U202 & U203). Powers on (or blips on rather), then back-lights go off. Power LED stays green and I can see still see what's on the screen with a light.




And I don't know if any of this was necessary or not, but for whoever is interested . . .
I tested Q102:
It seems good. Did diode checks and (blk) pin K - A1 (red) = .76 V & open with leads reversed. (blk) pin K - A2 (red) = .46 V & open with leads reversed. It seemed weird the values were different for each diode. In my limited experience a little variation is normal, but usually not that much. I know diff materials will yield diff results (IE: Germanium vs GaAs), but didn't think they are usually mixed from one diode to the next within the same component . Not sure if this is the case or not.


D102: https://cdn.badcaps-static.com/pdfs/...64704fcb16.pdf
Not sure how to test, as I am not familiar with the schematic. Looks like Zeners/Voltage regulators :-?

D101: I could not find the part. I tried both numbers and nothing came up. Looks like
PEC 626
SBC20200FCT


Point and I shall follow. Thanks

[jetadm123]

Re: Needs caps for my 22" lcd

Ok, so I ordered the MOSFETS, and they came in today
BUT, they measure the exact same as the ones that were suspected to be shorted Could it be possible I measured them wrong?

I referenced the pins according to the drawing, dot and notch at the bottom as shown in the drawing. I used the data sheet found here:


I referenced this also:


In anycase, It still does the same thing even after installation of the new MOSFETS (U202 & U203). Powers on (or blips on rather), then back-lights go off. Power LED stays green and I can see still see what's on the screen with a light.




And I don't know if any of this was necessary or not, but for whoever is interested . . .
I tested Q102:
It seems good. Did diode checks and (blk) pin K - A1 (red) = .76 V & open with leads reversed. (blk) pin K - A2 (red) = .46 V & open with leads reversed. It seemed weird the values were different for each diode. In my limited experience a little variation is normal, but usually not that much. I know diff materials will yield diff results (IE: Germanium vs GaAs), but didn't think they are usually mixed from one diode to the next within the same component . Not sure if this is the case or not.


D102: https://cdn.badcaps-static.com/pdfs/...64704fcb16.pdf
Not sure how to test, as I am not familiar with the schematic. Looks like Zeners/Voltage regulators :-?

D101: I could not find the part. I tried both numbers and nothing came up. Looks like
PEC 626
SBC20200FCT


Point and I shall follow. Thanks

Interesting that the S-G would also read 0.6 ohms on the new AOP605's. That reading indicates a clear short. Not sure what's going on with that.

Q102: Again, I'm not sure what you're doing here. Q102 is a mosfet with a Source, Gate and Drain. It's not your typical NPN or PNP transistor because the internal architecture is different. Instead of using the diode test fuction of your meter, just use the resistance setting and check S-G, G-D and S-D for a short.

D101 and D102 are each dual pack diodes, meaning each has two diodes built into the package. Every manufacturer has their own part number for these diodes. The key to locating the correct part is to use a partial listing. Try this for D101: go to the digikey.com website and enter "20200 diode" in the search window. Under "discrete semiconductor products" select diodes and you'll get the listing(s) you're looking for. Again, check them using the resistance setting.

[retiredcaps]

Re: Needs caps for my 22" lcd

BUT, they measure the exact same as the ones that were suspected to be shorted Could it be possible I measured them wrong?

1) What brand and model number is your multimeter? If possible post a picture with the probes plugged in.

2) What ohms reading do you get when you touch the two probes together?

3) On the AOP605, the dot is the "top". Pin 1 is to the left of the dot. So pin 3 and 4 are your S1 and G1. Retest with ohms and report your results.

4) Did you test the replacement AOP605 out of circuit before installing them?

[Nicks84]

Re: Needs caps for my 22" lcd

1)
a)Craftsman (Auto-ranging Multimeter) 82139 (see pic).
b)I have another yellow one that does read more accurately as far as resistance goes. I had it just days ago, but cant find it atm. Either way, it's a cheap Wal-mart special and can't recall the name.


2) .5 - .7 Ω is the lowest I get when I touch the probes together on an Ω test. I know that is not ideal, and I'm not sure why it is that high. But I got the meter from my cousin, for free. The probes are Fluke and do not seem to be damaged. I suspect the foul play is in the meter, unless it happens to be the leads themselves. But they do fit in correctly. If I find another pair, I will try them out. I know I had a meter that was a little wonky once, I cleaned the contacts inside and worked swimmingly, perhaps I will try that on this one.


3) *Measurements taken with notch on top and dot on top left (pin 1). Scale= Ω (anything under 1kΩ)

U202:
a) black on (pin 3) S1- red on pin G1(pin 4): OL
b) black on (pin 3) S1- red on pin D1(pin 5 & 6): OL & OL
c) black on (pin 4) G1- red on pin D1 (pin 5 & 6): OL & OL

Repeat for the "2" pins. That is:
(pin 1) S2-G2(pin2): OL
(pin 1) S2-D2(pin 7 & 8): OL & OL
(pin 2) G2-D2 (pin 7 & 8): OL & OL



**Scale on Auto range, scale (MΩ)
a) black on (pin 3) S1- red on pin G1(pin 4): 23.6 MΩ
b) black on (pin 3) S1- red on pin D1(pin 5 & 6): 12.5 MΩ & 12.3 MΩ
c) black on (pin 4) G1- red on pin D1 (pin 5 & 6): OL & OL

Repeat for the "2" pins. That is:
(pin 1) S2-G2(pin2): OL
(pin 1) S2-D2(pin 7 & 8): OL & OL
(pin 2) G2-D2 (pin 7 & 8): OL & OL (but sometimes[rarely] 23 & 30 kΩ)



U203= All measurements identical or super close (on both scales) to U202



4) Yes, I did, but I measure the new ones before installing, unfortunately I measured them the same way as I did the original ones (incorrectly) :-/ They were already installed before I was notified I had measure them wrong. I can pull them back out if needed. But they seem to measure similar to one of the old ones taken out. 1 of the 2 old ones measure lower Ω compared to all 3 of them, but on the same scale at least. (IE: where the new ones measure 30k, it measures 10k. Where the new ones measure 23k, it reads like 1K).

[Nicks84]

Re: Needs caps for my 22" lcd

Interesting that the S-G would also read 0.6 ohms on the new AOP605's. That reading indicates a clear short. Not sure what's going on with that.

I'm an idiot. I made the assumption (and a bad one at that) that the drawing from the data sheet (top & bottom view which showed the notch at the bottom & dot at bottom right), correlated withe the image directly next to it (pin diagram) I was wrong. Consequently it resulted in my chip being measure upside down. So my readings were not what they claimed to reflect. I have since updated the new ones in my previous post.

Q102: Again, I'm not sure what you're doing here. Q102 is a mosfet with a Source, Gate and Drain. It's not your typical NPN or PNP transistor because the internal architecture is different. Instead of using the diode test function of your meter, just use the resistance setting and check S-G, G-D and S-D for a short.

I had no idea what I was doing either, but I figured it couldn't hurt anything. I just saw what look liked to be diodes and figured at the least, they should drop a certain voltage. In the future, I will leave things like this to the professionals that know.

D101 and D102 are each dual pack diodes, meaning each has two diodes built into the package. Every manufacturer has their own part number for these diodes. The key to locating the correct part is to use a partial listing. Try this for D101: go to the digikey.com website and enter "20200 diode" in the search window. Under "discrete semiconductor products" select diodes and you'll get the listing(s) you're looking for. Again, check them using the resistance setting.

When searching for 20200 didode, I did get a result:

Not sure if that is the correct part or not. It seems almost identical to the SCHOTTKY RECTIFIER (less specific values). If I am not mistaken, this should drop (on a diode check) .5 -.7V on each diode and open with the leads reversed ? Or just stick to an Ω check ?

[retiredcaps]

Re: Needs caps for my 22" lcd

U203= All measurements identical or super close (on both scales) to U202

All those readings suggest the AOP605 mosfets are good.

[retiredcaps]

Re: Needs caps for my 22" lcd

It still does the same thing even after installation of the new MOSFETS (U202 & U203). Powers on (or blips on rather), then back-lights go off. Power LED stays green and I can see still see what's on the screen with a light.

This suggests it may be the

a) inverter transformer
b) ccfl
c) ccfl wiring

edit:

To test the inverter transformer, you will want to measure the resistance of these pins. Look at the attached pic. With power off and multimeter set to ohms, measure the resistance between the 2 yellow dots. Do the same for the red dots. Report findings.

[Nicks84]

Re: Needs caps for my 22" lcd

The resistance between red pins and yellow pins both read .7 Ω & .8 Ω
And on this meter that I am using, we have discussed in the previous post, that's about as low as it goes.

[jetadm123]

Re: Needs caps for my 22" lcd

When searching for 20200 didode, I did get a result:

Not sure if that is the correct part or not. It seems almost identical to the SCHOTTKY RECTIFIER (less specific values). If I am not mistaken, this should drop (on a diode check) .5 -.7V on each diode and open with the leads reversed ? Or just stick to an Ω check ?

A regular diode will have a voltage drop between 0.6-1.7V, whereas a schottky diode will have a drop of 0.15-0.45V.

Because of the larger current capabilities of these heatsinked diodes, when they fail they have a tendency to short out. A resistance test will quickly determine that.

The resistance between red pins and yellow pins both read .7 Ω & .8 Ω
And on this meter that I am using, we have discussed in the previous post, that's about as low as it goes.

You initial testing of the inverter transformers would indicate they are shorted out. However, I find it hard to believe that both (but not impossible) transformers have failed. You may need to remove the transformer from the board and perform your resistance check again.

[retiredcaps]

Re: Needs caps for my 22" lcd

Hmm, I think I misidentified the secondaries.

1) What is the part number of the 2 transformers?

2) Let's try the long way as described in #4 at

https://www.badcaps.net/forum/showpo...1&postcount=14

It looks like you have 11 pins per transformer. 7 on one side, 4 on the other. Some readings will be 0.7 ohms, others 0L, and others in between (like around 950 ohms). It is the in between ones that we are interested in.

[Nicks84]

Re: Needs caps for my 22" lcd

Hmm, I think I misidentified the secondaries.

1) What is the part number of the 2 transformers?

2) Let's try the long way as described in #4 at

https://www.badcaps.net/forum/showpo...1&postcount=14

It looks like you have 11 pins per transformer. 7 on one side, 4 on the other. Some readings will be 0.7 ohms, others 0L, and others in between (like around 950 ohms). It is the in between ones that we are interested in.

1) Yes, I have 11 pins on the X-former. I labeled the Primaries 1-7 & Secondaries 8-11. (see pic below).
Nothing on the transformer did me any good. Not even a Google search yielded results, but here ya go:

2874001100
M F 628 A

(The other X-former is the exact same as you can see below, just labeled what seems to be marked "B" on the bottom right. Where as the 1st X-former is marked "A". But under close inspection, I really can't tell if they're both supposed to be marked "B" ? (This is not to be confused with the "A" after the 628).




2)
Scale on kΩ [value in parenthesis= (Auto-range). If no value is shown, then it reads the same as kΩ scale].





Inverter transformer: B

Primary:
1) black probe on pin 1, red on pin 2: OL (13 MΩ)
2) black probe on pin 1, red on pin 3: OL (13 MΩ)
3) black probe on pin 1, red on pin 4: OL (13 MΩ)
4) 1 - 5: OL (13 MΩ)
5) 1 - 6: OL (13 MΩ)
6) 1 - 7: OL (13 MΩ)

2ND:
7) 1 - 8: 365 Ω
8) 1 - 9: 368 Ω
9) 1 - 10: OL
10) 1 - 11: OL



Primary:
11) 2-3: 0 (.7Ω)
12) 2-5: 0 (.6Ω)
13) 2-6: 0 (.6Ω)
14) 2-7: 0 (.8Ω)

2nd:
15) 2 - 8: OL (8.75MΩ)
16) 2 - 9: OL (8.74MΩ)
17) 2 - 10: OL
18) 2 - 11: OL


Primary:
19) 3 - 4: 0Ω (.5Ω)
20) 3 - 5: 0Ω (.5Ω)
21) 3 - 6: 0Ω (.5Ω)
22) 3 - 7: 0Ω (1 Ω)

2nd:
23) 3 - 8: OL
24) 3 - 9: OL
25) 3 - 10: OL
26) 3 - 11: OL


Primary:
27) 4 - 5: 0Ω (.6 Ω)
28) 4 - 6: 0Ω (.7 Ω)
29) 4 - 7: 0Ω (.6 Ω)

2nd:
30) 4 - 8: OL (9.60 MΩ)
31) 4 - 9: OL (9.60 MΩ)
32) 4 - 10: OL
33) 4 - 11: OL

Primary:
34) 5 - 6: 0Ω (.6 Ω)
35) 5 - 7: 0Ω (.5Ω)

2nd:
36) 5 - 8: OL (9.8MΩ)
37) 5 - 9: OL (9.78MΩ)
38) 5 - 10: OL
39) 5 - 11: OL

Primary:
40) 6-7: 0Ω (.8 Ω)

2nd:
41) 6 - 8: OL (1.54 MΩ)
42) 6 - 9: OL (1.54 MΩ)
43) 6 - 10: OL
44) 6 - 11: OL


45) 7 - 8: OL (1.54 MΩ)
46) 7 - 9: OL (4MΩ)[starts at 10 M and slowly but constantly drops to right under 4, then toggles around 4 MΩ)
47) 7 - 10: OL
48) 7 - 11: OL

49) 8 - 9: 0Ω (.6 Ω)
50) 8 - 10: OL
51) 8 - 11: OL

52) 9 - 10: OL
53) 9 - 11: OL

54) 10- 11: OL



If the format of these readings are satisfactory, then I will provide the data for the other Inverter asap. If you want me to exclude the value in parenthesis (auto-range), let me know . I realize this is a lot of data and can become cluttered easily. Just thought I'd do one and get approval before moving on.

[retiredcaps]

Re: Needs caps for my 22" lcd

2ND:
7) 1 - 8: 365 Ω
8) 1 - 9: 368 Ω

1-8 and 1-9 are the ones we are interested in.

[Nicks84]

Re: Needs caps for my 22" lcd

The ones of interest are:
1 - 8: 365 Ω
1 - 9: 368 Ω

For X-former A:
1 - 8: 365 Ω
1 - 9: 364 Ω

They measure pretty much the same. I guess by this, they are either both good or both hosed ? What to do next, boss ? Do I need to remove and measure ?

[retiredcaps]

Re: Needs caps for my 22" lcd

For X-former A:
1 - 8: 365 Ω
1 - 9: 364 Ω

All the inverter transformers look okay since the readings are within 3% of each other.

If you have another lcd (doesn't have to be working, try stretching out just one (at a time) the ccfl connector from the 22 inch lcd to the spare one.

More details at (see #5)

https://www.badcaps.net/forum/showpo...1&postcount=14

Examples of bad ccfl/ccfl wiring

http://s807.photobucket.com/albums/y...klight%20lamp/

[Nicks84]

Re: Needs caps for my 22" lcd

Okay, steps for troubleshooting above are good. However, I have 2 problems concerning that:
1)do not happen to have a known good set of ccfl's laying around of the same size/type.

2) I do not see how to get to remove or the ccfls from the Westinghouse


Moving onward, I did find an LCD in the trash the other day. It's a Dell E172fpb. I did not expect it to work, but I was hoping that maybe the lamps were good (and they are)

I plugged up the Dell and get no kind of power, no led, no noise, nothing. So the monitor seems like it's dead power-wise (to be expected). But for grins, since I had to open it up to acess the ccfl/s, I checked the fuse, its good. I see like 5 bulging caps inside and nothing visually burnt. But again, at this point my only concern is the ccfls from the Dell.


In anycase I: (taking into consideration that the ccfl's from the Dell are smaller that the ones in the Westinghouse.)

1) I plug the wires that go to the ccfl from the Dell into the output harness of my Westinghouse. One by one, I get a 1 second flash, then goes to black (as does with the Westinghouse). But when plugging up both ccfl's (from Dell), both lights light up and stay on as they should,


I am assuming by that, the board in the Westinghouse is outputting properly and that one of my bulbs in the Westinghouse is the culprit? How does that sound to you ?

Where to go from here? I assumed I wanted to remove or access my ccfl's from the Westinghouse either for further testing/inspection, but I don't know how. I did Google it but found nothing useful. Just R&R of laptop ccfls mostly. Any pointers?

*If any of this was unclear, please ask

[PlainBill]

Re: Needs caps for my 22" lcd

Okay, steps for troubleshooting above are good. However, I have 2 problems concerning that:
1)do not happen to have a known good set of ccfl's laying around of the same size/type.

2) I do not see how to get to remove or the ccfls from the Westinghouse


Moving onward, I did find an LCD in the trash the other day. It's a Dell E172fpb. I did not expect it to work, but I was hoping that maybe the lamps were good (and they are)

I plugged up the Dell and get no kind of power, no led, no noise, nothing. So the monitor seems like it's dead power-wise (to be expected). But for grins, since I had to open it up to acess the ccfl/s, I checked the fuse, its good. I see like 5 bulging caps inside and nothing visually burnt. But again, at this point my only concern is the ccfls from the Dell.


In anycase I: (taking into consideration that the ccfl's from the Dell are smaller that the ones in the Westinghouse.)

1) I plug the wires that go to the ccfl from the Dell into the output harness of my Westinghouse. One by one, I get a 1 second flash, then goes to black (as does with the Westinghouse). But when plugging up both ccfl's (from Dell), both lights light up and stay on as they should,


I am assuming by that, the board in the Westinghouse is outputting properly and that one of my bulbs in the Westinghouse is the culprit? How does that sound to you ?

Where to go from here? I assumed I wanted to remove or access my ccfl's from the Westinghouse either for further testing/inspection, but I don't know how. I did Google it but found nothing useful. Just R&R of laptop ccfls mostly. Any pointers?

*If any of this was unclear, please ask

It sounds like you have correctly identified the problem. Retiredcaps sometimes posts a link to instructions for replacing the CCFLs on a monitor.

PlainBill

[retiredcaps]

Re: Needs caps for my 22" lcd

However, I have 2 problems concerning that:
1)do not happen to have a known good set of ccfl's laying around of the same size/type.

As long as the size is close or comparable, it should work most of the time (as you found out). Carefully check the wiring/soldering as the ccfls themselves may be good.

2) I do not see how to get to remove or the ccfls from the Westinghouse

Members here report excellent service from ccflwarehouse.com.

They have a tutorial on how to install new ccfls.

http://www.ccflwarehouse.com/lasotu.html

ccfldirect.com has a tutorial on how to remove the ccfls from a laptop so the instructions are similar to a lcd

http://ccfldirect.com/lcdtutorial.html

PS. Open up a new thread for the trash find Dell. I already have test suggestions for the no power problem.