Viewsonic Monitor VS11618/VA1903WB

[simplytrini]

Hi all new here, hoping to find some help with a monitor I trying to repair. This Monitor came in with power led not lighting at all on the front panel, when I checked the Power supply I can't find any faulty components. I checked the cap's all are good non leaking or swollen ever DCR & ESR are good. I checked transistors and resistors and all seem good. When check voltages I have 12v & 5v. not exactly sure where to go from here.

Has anyone seen this problem before? Any ideas would be helpful. Thanks

[jetadm123]

Since you've provided no photos of your boards, then that's equivalent to asking members to guess at what your problem is. Since you're getting no power light, yet getting 5V and 12V outputs, I'm thinking a failed reset controller. Usually labelled U405 or U406 on the logic board. If you remove this controller, it should power up. Again, due to lack of photos, proceed at your own risk.

[simplytrini]

Thanks jetadm123 I will post pics shortly.

[Rtech]

Another 'sharper' picture of the Logic board may be very helpful,as that looks to be where the fault lies.

[simplytrini]

These images should be better

[simplytrini]

I tried to upload new pics but it fails every time i try. I will try again in a bit. Thanks again.

[simplytrini]

Hi jetadm123, I apologize for my lack of photos again. However I have followed your suggestion and removed U406 and as you said the monitor did pwr on, thanks you for that. Now that I have determined that U406 is the issue do I just replace the IC? or does it need to be re programmed? I was looking at the Datasheet and because of the type of chip that it is I am not sure of the replacement method. Again I really appreciate your help with this unit. Thanks

[jetadm123]

The part in question is a MAX810STRG reset controller. It is not programmed, but a generic part and can be easily purchased through many sources. Others that have removed this controller have not had any further problems. However, if you feel you must/should replace it, then it's rated at a threshold of 2.93V and can be purchased through digikey.com:

http://search.digikey.com/scripts/Dk...0SEUR%2BTCT-ND

[simplytrini]

Originally Posted by jetadm123

The part in question is a MAX810STRG reset controller. It is not programmed, but a generic part and can be easily purchased through many sources. Others that have removed this controller have not had any further problems. However, if you feel you must/should replace it, then it's rated at a threshold of 2.93V and can be purchased through digikey.com:

http://search.digikey.com/scripts/Dk...0SEUR%2BTCT-ND

U406 on my PCB is labelled M24C04-WMN6TP SO8. It is an 8 pin chip. Is this MAX810STRG reset controller related to the M24C04-WMN6TP SO8 chip? Or am I talking about something totally different? I don't have the unit with me right now to look at the component layout.

Again I know I should provide a pic but every time I try to upoad pics I get file upload failed message. Not sure what I am doing wrong. Any thought on this?

Is there another way for me to send you the pic?

Thank you very much!

[jetadm123]

Unfortunately, what you removed is an eeprom. The reset controller is a 3-legged device. The link I provided has a datasheet for it. What was U405?

[simplytrini]

Originally Posted by jetadm123

Unfortunately, what you removed is an eeprom. The reset controller is a 3-legged device. The link I provided has a datasheet for it. What was U405?

Can't find a U405, I got pics this time.

[jetadm123]

I can barely make it out. It looks like U405 was printed on the circuit board, but was not used. Not sure why removing U406 allowed the monitor to work. This possibly could be a eeprom that stores user settings made using the on screen display (OSD) menu. You can verify by changing a setting on the menu, turning the monitor off for a minute and back on to see if the menu setting was saved.

[simplytrini]

Thanks for all your help. I reinstalled the U406 and everything works now. Not sure if there was a bad solder joint, but it works now. Thanks again