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Old 01-07-2011, 08:33 PM   #21
briand
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

thanks for the suggestions.

attached is my DigiKey order... I would appreciate verification that I selected a suitable replacement for the 120uF/400V capacitor.
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File Type: jpg DigiKey-VX1940w-Order.jpg (101.1 KB, 38 views)
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Old 01-07-2011, 09:22 PM   #22
retiredcaps
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

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Originally Posted by briand View Post
I would appreciate verification that I selected a suitable replacement for the 120uF/400V capacitor.
Assuming the diameter and height are correct, Panasonic is fine.
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Old 01-08-2011, 10:11 AM   #23
briand
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

...for those following along at home and/or vicariously repairing monitors through my experience, I've attached an image indicating the parts being replaced.

C1 and C302 are definitely bad (bulged)

C201 is questionable.

C205, C305, and C307 are being replaced in a preventative manner, as they are of the same quality as the failed capacitors (5x CapXon, 1x VENT). All being replaced by Panasonic caps.
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File Type: jpg B092-XXX_annotated.jpg (654.8 KB, 130 views)
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Old 01-08-2011, 10:31 AM   #24
Kridian
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

Post an after pic on the new ones installed.
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Old 01-08-2011, 11:08 AM   #25
briand
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

okay, I will.

life may intervene, so it may be a week or two before I get around to completing the repair.
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Old 01-15-2011, 03:40 PM   #26
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

first msg on this great forum. Finally found this thread I was looking for. My monitor is model VX1940wm to be exact.

I have _exactly_ the same story as briand. Had VX922 and it was replaced to this monitor and it failed too. First time I changed only the 2 bulged caps, and the monitor worked like 1-2 month(s). After the first repair, one vertical cyan line appeared on the screen after heating up. By pressing the screen the line disappeared. Don't know it this is due some bad connection or connector.

Anyways, the monitor went completely dead. Decided to change all caps then and I'm also waiting the parts now. I will get back when I get it completed :P
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Old 01-15-2011, 11:28 PM   #27
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

welcome to the forum, Neobyte.

my parts are in-transit. Digi-Key backordered one of the caps, so I ordered it from Mouser... also found a 120uF/400V radial lead replacement (Nichicon) at Mouser as well; the Panasonic unit from Digi-Key was a 'snap-in' with two short posts.

I should, hopefully, have all the parts by mid-week, and have my 19" WS monitor back online by next weekend.
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Old 01-17-2011, 08:11 AM   #28
Neobyte
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

Recapped the monitor now. Didn't help anymore. Must be some other component failing? Don't know what. Here's image of the smps-board..
It's trash unless someone figures any tricks
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Old 01-17-2011, 08:26 AM   #29
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

Quote:
Originally Posted by Neobyte View Post
first msg on this great forum. Finally found this thread I was looking for. My monitor is model VX1940wm to be exact.

I have _exactly_ the same story as briand. Had VX922 and it was replaced to this monitor and it failed too. First time I changed only the 2 bulged caps, and the monitor worked like 1-2 month(s). After the first repair, one vertical cyan line appeared on the screen after heating up. By pressing the screen the line disappeared. Don't know it this is due some bad connection or connector.

Anyways, the monitor went completely dead. Decided to change all caps then and I'm also waiting the parts now. I will get back when I get it completed :P
What do you mean completly dead?Have you checked all the fuses?
Al.
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Old 01-17-2011, 09:23 AM   #30
Neobyte
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

No power at all. Power led doesn't go on. Ermm, I found 3 fuses total, F1 (surface mount) on the 'long board', and psu-board F101 and F301. They all measured close to 0 ohms. Dunno if there's more of them? :P
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Old 01-17-2011, 09:53 AM   #31
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

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Originally Posted by wcperki View Post
The 2 Viewsonic X1940W LCD monitors I bought as a dual monitor set are both not working. They are still underwarranty but I could'nt help myself I had to take one apart. I could use some help getting the right caps ordered.
I tried mouser and digikey but gave up. I'd prefer to just order from badcaps.net but here too I run into a roadblock with exact matches.
I'd like to know what I can safely use to replace the following caps. Also, can anyone tell me how does one remove the epoxy glue inorder to de-solder?
Pictures are attached.
C1
CapXon
GF105
P735 vent
220μF 35v
D=10mm x L=12mm x LEAD SPACE=5mm

C302
CapXon
GF105
P735 vent
220μF 35v
10mm x 12mm x 5mm

C305
CapXon
GF 105 c
P735 vent
2200μF 10V
13mm x 18mm x 5mm

C307
CapXon P735 vent
KF 105c
1000μF 10V
8mm x 20mm x4mm

C205
KF105 P733
50V 22μF
5mm X 8MM x 3mm


Thanks,
Warren
First make sure the caps are bad. Second you can carefully cut the glue with an exacto, avoiding board scaring, these caps you list can be found in other power supplies and controls. Just be sure to check the replacements before install. K!
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Old 01-17-2011, 09:56 AM   #32
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

Can someone tell me if there is an nte, or other cross number for a 13n07 mos transistor out of a dell 1704fpt
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Old 01-17-2011, 10:01 AM   #33
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

Quote:
Originally Posted by Neobyte View Post
No power at all. Power led doesn't go on. Ermm, I found 3 fuses total, F1 (surface mount) on the 'long board', and psu-board F101 and F301. They all measured close to 0 ohms. Dunno if there's more of them? :P
The power LED is a 'fly by wire' arrangement. It is controlled by the processor on the signal (logic) card. Check the output voltage of the power supply. If that is missing, check the voltage across the large (100F, 450 volt) cap. If the output voltage is present, check for a reset controller on the signal card.

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Old 01-17-2011, 10:16 AM   #34
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

PlainBill, I tried to measure the voltages. I suppose the output is the connector going to the logic board? There wasn't much voltage present. Then I checked the large cap, the voltage was ~105V. Is that toasted too? (I did not change that during my recap operation)

edit: Btw I have 230V mains.

Last edited by Neobyte; 01-17-2011 at 10:20 AM..
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Old 01-17-2011, 10:36 AM   #35
retiredcaps
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

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Originally Posted by Neobyte View Post
Then I checked the large cap, the voltage was ~105V. Is that toasted too?

edit: Btw I have 230V mains.
How are you measuring that voltage across the large cap. Is that 105 AC or DC that you are measuring?
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Old 01-17-2011, 10:58 AM   #36
Neobyte
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

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Originally Posted by retiredcaps View Post
How are you measuring that voltage across the large cap. Is that 105 AC or DC that you are measuring?
Black, ground from the corner screw area and red to the positive leg of the cap. My meter was at 600V (DC).. I don't have too much experience measuring these things.
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Old 01-17-2011, 11:22 AM   #37
retiredcaps
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

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Originally Posted by Neobyte View Post
Black, ground from the corner screw area and red to the positive leg of the cap.
To measure the DC voltage across the large cap, put your black in COM and red into Volts on your multimeter.

Then put your black probe on the negative leg of the main filter cap. Put your red probe on the positive leg of the main filter cap.

You should get 230V x 1.414 rectified DC voltage or about 325V DC.
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Old 01-17-2011, 11:44 AM   #38
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

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You should get 230V x 1.414 rectified DC voltage or about 325V DC.
Ok, I got 321V from there
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Old 01-17-2011, 11:49 AM   #39
retiredcaps
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

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Originally Posted by Neobyte View Post
Ok, I got 321V from there
Okay, let's retest for the secondary voltages.

Put your black probe on a screw near the connectors. This is your ground. Put your red probes on each connector (CN301) and report each DC voltage on each connector pin. Put your multimeter on 20V DC.

edit: Pin 1, 2, and 3 according to the legend should be 5V DC.

Last edited by retiredcaps; 01-17-2011 at 11:52 AM.. Reason: pin 1,2,3
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Old 01-17-2011, 12:04 PM   #40
Neobyte
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Default Re: 2 Viewsonic VX1940W buzzing and no signal

Yes it should be 5V. Every pin shows close to zero voltage (maybe it's zero then). <0,1V anyways.
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