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Old 04-03-2018, 10:40 PM   #1
MicroBell1
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Default BenQ Q22W6 Capacitor Replacement

Greetings All,

I need advise on another monitor project that requires capacitor replacement and need to make sure I'm ordering the correct parts and to confirm I'm looking at the correct problem/diagnosis.

Monitor: BenQ Q22W6
Board Ver: 4H.03V02.A02

Problem: A few days ago the monitor (using as TV now) went blank and the green signal light stayed on. The monitors menu and picture would pop up for a second or two and then go blank. After investigation when you hold a flashlight up to the screen you can see the picture in the background. So I suspect back-light inverter or power issue.

Diagnosis: After disassembly I located 5 bulging caps on the power side and I'm currently in the process of getting them (doing all caps) but wanted to confirm that what I'm ordering is correct.

Original Caps:

Elite 470uf 35V (4 bulging)
Elite 220uf 25v (1 bulging)
FDAI CD112A 47uf 50v (none ) <-------- This is the one I'm curious about as it's replacement looks smaller (in can size) then the original.

Replacement Caps:

Panasonic 470uf 35v https://www.digikey.com/product-deta...0301-ND/266310
Panasonic 220uf 25v https://www.digikey.com/product-deta...3CT-ND/6109541
Panasonic 47uf 50v https://www.digikey.com/product-deta...0321-ND/266330

Back in 2013 I used Panasonic to replace bad caps in a Hanns-G HG281D with help from you all and that monitor is still up and going strong. Please let me know if these will be fine or recommend another brand in that price range and also can these bad caps cause the issue I'm looking at? (Hopefully so...lol)

Thanks much!!

Note: Images can also be found here https://imgur.com/a/Xk9hA
Also went over the boards with a magnifying glass and saw nothing blown that could indicate another issue though components were not tested yet.
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Last edited by MicroBell1; 04-03-2018 at 10:47 PM..
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Old 04-06-2018, 03:38 AM   #2
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Default Re: BenQ Q22W6 Capacitor Replacement

Gents,

Going to be ordering these later today and still need advice on my replacement choices....specifically that FOAI CD112A Cap as I'm unfamiliar with that name brand and it's markings (Chinese Maybe).

Thanks!
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Old 04-07-2018, 04:33 AM   #3
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Default Re: BenQ Q22W6 Capacitor Replacement

Elite brand are cheap capacitors (Chinese) and FOAI are even cheaper. They are discussed here:

https://www.badcaps.net/forum/printthread.php?t=37835

I would go ahead and change all those caps, even the big one 120uf 450V. I don't usually change a primary cap, but because it is an Elite, I would.

Panasonic are probably the best choice, so you're doing the right thing.

Change all of them, even those that are not bulging because one or a few are probably the source of your problem.

Good luck!
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Old 04-07-2018, 05:06 AM   #4
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Default Re: BenQ Q22W6 Capacitor Replacement

Quote:
Originally Posted by rddube View Post
Elite brand are cheap capacitors (Chinese) and FOAI are even cheaper. They are discussed here:

https://www.badcaps.net/forum/printthread.php?t=37835

I would go ahead and change all those caps, even the big one 120uf 450V. I don't usually change a primary cap, but because it is an Elite, I would.

Panasonic are probably the best choice, so you're doing the right thing.

Change all of them, even those that are not bulging because one or a few are probably the source of your problem.

Good luck!

Thanks for your input rddube! I was changing them all except the primary cap as it usually isn't a problem. If you think it needs replaced can you suggest a replacement on DigiKey?

I could not find one under the Panasonic brand. And what kind of glue (or something I have at home) holds that cap down?
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Old 04-07-2018, 06:48 AM   #5
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Default Re: BenQ Q22W6 Capacitor Replacement

Yep, on DigiKey...if Panasonic are not available, then I go for Rubycon or Nichicon. The glue can be hot glue.

Let us know how it turns out!
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Old 04-07-2018, 03:16 PM   #6
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Default Re: BenQ Q22W6 Capacitor Replacement

Sorry...I Meant can you suggest one (The Cap). Anyway I'm going to include this one in my order... https://www.digikey.com/product-deta...308-ND/4319373

Please let me know if that one will work fine (UPZ series) or do you recommend another series?

*Note*

Slight concern about the smaller size and length of leads.

Last edited by MicroBell1; 04-07-2018 at 03:20 PM..
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Old 04-07-2018, 08:18 PM   #7
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Default Re: BenQ Q22W6 Capacitor Replacement

That one will be just fine. Don't worry about the size, the brand and the fact that they are Japanese made is what matters. 1st choice Panasonic, but Nichicon and Rubycon are just as good.
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Old 04-13-2018, 05:49 AM   #8
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Default Re: BenQ Q22W6 Capacitor Replacement

So MicroBell1, any developments on your cap changing?
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Old 04-16-2018, 04:16 AM   #9
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Default Re: BenQ Q22W6 Capacitor Replacement

Quote:
Originally Posted by rddube View Post
So MicroBell1, any developments on your cap changing?
Not yet rbdube. All parts are in but I'm awaiting a return for a defective soldering iron and my Rosin flux from Amazon (thought I had some but didn't)....as it appears that no one...and I mean no one carries Rosin based flux for electrical work in my area.

Should happen this week once everything gets here.

Last edited by MicroBell1; 04-16-2018 at 04:17 AM..
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Old 04-23-2018, 02:36 PM   #10
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Default Re: BenQ Q22W6 Capacitor Replacement

Update:

Well Cap replacement went ok (though I lifted one trace a little that I had to fix) but the issue remains. The BenQ logo comes up for a sec....goes black..then the desktop...then black again with the Green LED on.

Looked for that C5707 Transistor listed in the sticky but could not find on my board. Little concerned by the discolored heat areas on the power board....but I'm now looking at the logic board also.

Nothing stood out (No bulging caps, burnt parts..etc) but was noted on the pictures posted....so looking for advice on next step or something I may have overlooked.
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Old 04-24-2018, 07:26 AM   #11
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Default Re: BenQ Q22W6 Capacitor Replacement

I would measure the output of those 2 inverter transformers (no power applied) for resistance - tell us what each one gives you in resistance they should be fairly equal.
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Old 04-24-2018, 02:20 PM   #12
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Default Re: BenQ Q22W6 Capacitor Replacement

Quote:
Originally Posted by rddube View Post
I would measure the output of those 2 inverter transformers (no power applied) for resistance - tell us what each one gives you in resistance they should be fairly equal.
Apologies for being stupid at electronics....but would you be kind enough to circle the pins I need to test on my picture?

Still trying to learn how to ID things like "Inverter Transformer", "Backlight Inverter", "Transformer"...etc. and how they are connected through the circuitry on the board and which are the "in" and "out" power pins as this is only the second monitor I've attempted a fix for.

Hard to find a breakdown of a simple LCD monitor motherboard that lists with pictures "This is This"..... These are the inputs....outputs"...etc.
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Old 04-24-2018, 03:22 PM   #13
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Default Re: BenQ Q22W6 Capacitor Replacement

Ok, no problem. I have marked the pins for you.

Make sure you don't have power on the board as this is the high voltage side, just measure resistance (ohms) of both sets.

Ray
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Old 04-25-2018, 05:12 AM   #14
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Default Re: BenQ Q22W6 Capacitor Replacement

Hi,

You might want to take a look at this thread https://www.badcaps.net/forum/showth...er+transformer

although it is not the same brand than yours (so probably the components are different) it gives you an idea where the problem may lie. It uses the same caps you had i.e. Elite, and I suspect that the transformers where you indicate a heat problem may have overheated at least one of them. So check those resistances in the previous post and let us know what you find.

If your inverter transformers are good, then I would suspect the CCFL's. Budm has a great sticky on how to test the CCFLS's using plain cfl lights https://www.badcaps.net/forum/showthread.php?t=19987

Last edited by rddube; 04-25-2018 at 05:14 AM..
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Old 04-25-2018, 03:34 PM   #15
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Default Re: BenQ Q22W6 Capacitor Replacement

Thanks rddube and I'll look at that thread. As for the Inverters I got a reading of .387 on the top and .383 on the bottom (Ref your pic) so I'm assuming they are fine as both numbers are close?

I did previously look at Budm's thread but I have no spare CFL's to test with so I'm kinda doing the hit and miss thing on locating the problem.

**Note**

Going to do some cleanup in that inverter area and maybe re-float the pins. I bought this monitor new but it almost seams like someone did a repair there with all the flux and stuff and one solder joint seams wacky to me (solder mound really high) like it was done quickly by hand using too much solder.

Last edited by MicroBell1; 04-25-2018 at 03:51 PM..
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Old 04-25-2018, 04:03 PM   #16
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Default Re: BenQ Q22W6 Capacitor Replacement

Quote:
Originally Posted by MicroBell1 View Post
Thanks rddube and I'll look at that thread. As for the Inverters I got a reading of .387 on the top and .383 on the bottom (Ref your pic) so I'm assuming they are fine as both numbers are close?

I did previously look at Budm's thread but I have no spare CFL's to test with so I'm kinda doing the hit and miss thing on locating the problem.

**Note**

Going to do some cleanup in that inverter area and maybe re-float the pins. I bought this monitor new but it almost seams like someone did a repair there with all the flux and stuff and one solder joint seams wacky to me (solder mound really high) like it was done quickly by hand using too much solder.
Not too sure what you mean by .387 and .383, is that kilo ohms? That would mean approx 387 ohms, which I think is ok....if it is ohms however, that is a short.

It could be a bad solder joint, so try that at first, but I am starting to suspect one of your ccfl tubes. Let me know if it's kilo ohms or ohms and as for spare CFL lights, they can be purchased for 2-3$ at the dollar store, just make sure it's the right wattage.

You might also want to inspect the wires connecting your ccfl tubes...can you see the end of them on the tube ...if you followed BUDM's procedure we could eliminate or confirm the ccfls
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Old 04-26-2018, 02:49 PM   #17
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Default Re: BenQ Q22W6 Capacitor Replacement

Hey rddube,


Not sure what's going on with this old 1980's meter I borrowed from my Dad but I'm going to try and get a new one this weekend. Those numbers I posted were indeed in "Kilo Ohms" and when this meter is set to just Ohms I get 100.0 with the "1" flashing on all four of those pins....which I would assume is a "Open" circuit.

Would both inverter transformers go at the same time or is something else in that circuit breaking the connection. I'm just not trusting this multimeter as it's very old and appears to be some "RipOff" of a Sears model number 82417.

Can find no manual or picture of this meter anywhere....and although the case says Sears (Kinda scratched out on purpose) and model 82417 it's not that model...lol. So I'll try and get a new one and report back with more accurate readings.
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Last edited by MicroBell1; 04-26-2018 at 03:14 PM.. Reason: Added some pics for old meter
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Old 04-28-2018, 04:51 AM   #18
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Default Re: BenQ Q22W6 Capacitor Replacement

It's hard to tell without accurate readings. My Benq monitor inverter transformers measure
+- 465 ohms, so if yours are at 100 ohms that sounds low, but hey what is the exact measurement?

BTW, your photos are quite blurry and dark or I need glasses?

If it were my multimeter, I'd open her up and see what the PCB revision and maybe brand is and you could cross reference it and try the find the real manufacturer with some instructions..just a suggestion.

Last edited by rddube; 04-28-2018 at 04:55 AM..
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Old 04-28-2018, 07:31 PM   #19
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Default Re: BenQ Q22W6 Capacitor Replacement

Quote:
Originally Posted by rddube View Post
If it were my multimeter, I'd open her up and see what the PCB revision and maybe brand is and you could cross reference it and try the find the real manufacturer with some instructions..just a suggestion.
That was my thought as well but proved worthless. The board only has component numbers stamped for the components. No Brand, PCB numbers or any other writings or markings on either side of the board.

Anyway after I opened it up... I noticed damage from the 10amp/COM to the board. Burnt through the wire connecting from the steel rod plane to the motherboard, fried one leg of the steel bar (which is now black and corroded because of high heat) , and melted the plastic contact points where the steel bar rests so there was some serious juice flow going the wrong way....lol.

Just going to pitch and replace it. Thanks for the Idea though and I'll get you those new numbers as soon as I can.
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Old 04-30-2018, 02:45 PM   #20
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Default Re: BenQ Q22W6 Capacitor Replacement

Elite 470uf 35V (4 şişkinlik) =470uf50v:680uf35v:1000uf35v okey
Elite 220uf 25v (1 şişkinlik) 220uf35v:330uf25v:470uf25v:680uf25v okey
FDAI CD112A 47uf 50v:47uf63v:68uf50v okey
Deformed main board ve power supply Card
There is Change
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