Viewsonic VX715 problem

[Dgtech]

Re: Viewsonic VX715 problem

If you are lucky, you just blew the cap that you turned around and a fuse. If the unit was working at any point with the cap in the position that you found it, you should have kept it in that same position. I hope you didnt blow anything else. The first thing I would do is simply this. In your first post you said that you had replaced one obvious bad 1000uF/16v cap. You should have changed them all. Second, correct the polarity of the one cap - put it back the direction you found it in. Third, check the fuses - you may have to replace one if it's blown. After you do those things, power it up and see what you got.

[retiredcaps]

Re: Viewsonic VX715 problem

so I inspected the board again, did some touch-up soldering on some components

BTW, some of the solder joints look suspect to me in the photo. See

http://workmanship.nasa.gov/lib/insp...uirements.html

on what good/bad joints look like.

[retiredcaps]

Re: Viewsonic VX715 problem

1) Use your dmm and test each component. You can test many components without the power plugged in. Use ohm to look for shorts in transistors and transformers.

2) I learned by looking at videos on youtube. You can search by entering

how to measure transistor using dmm
how to measure transformer using dmm
how to measure diodes using dmm
etc
etc

The front pic of the board is way out of focus. Take this board to a window on a sunny day and put your camera on macro mode. This will yield nice clearly focused pictures.

Here is a pic I took next to the window. It is top down and you can see everything clearly.

https://www.badcaps.net/forum/attach...chmentid=16690

3) What brand of capacitors did you use to replace the bad ones.

Got a Viewsonic VX715
symptom - screen display flashing every 2-3 sec,

1)how do I know, did I fried the transformer or any other components?
2)Where do I need to measure (resistance or voltage) to determine whether to change any other components?

i've attached the images of the power board.. apologies if its not good enough

[newbie1]

Greetings from Asia

Virgin thread here... kindly be gentle.. heee..

firstly, I have only limited experience & expertise
tools I have now
1)DMM (w/out capacitor measurement)
2)soldering tools..
3)tiny-winy magnifying glass

ok here goes, sorry to be long winded...

Got a Viewsonic VX715
symptom - screen display flashing every 2-3 sec,

so I changed one of the 1000uF/16v cap (the one lying down) coz it was a little bloated,
no change, the screen display still flashing every 2-3 sec,

so decide to leave it there while I enjoy a good game of soccer (World cup 2010),...
during halftime, I discovered screen display is black.

Switch off & on again, it now becomes the classic 3 sec to black..
so I inspected the board again, did some touch-up soldering on some components
but was surprised to see the other 1000uF/16v cap (the one standing up)
-ve is facing the heatsink while I saw clearly on the PCB marking printed that it was supposed to be -ve facing outwards.. YIKES!
desoldered it,.. another surprise comes,
beneath it there is a marker pen indicating -ve is should be facing the heatsink,..
confused..
so decide to follow the PCB marking printed.. power it up..
then >>>> *POP*.. + acrid smell.. DAMNED!..
traced to be around the transformer, I think,
inspected the board again, but can't see any burnt area/component

1000uF/16v cap (the one standing up) swelled, but display is still 3 sec to black..
changed the swelled 1000uF/16v cap... THIS time -ve facing inwards.. power it up
but display is still 3 sec to black..

Hope somebody can help me out on my next step/s....
1)how do I know, did I fried the transformer or any other components?
2)Where do I need to measure (resistance or voltage) to determine whether to change any other components?

Any other suggestions are welcome

i've attached the images of the power board.. apologies if its not good enough.. ignore the pix dates as i have forgotten to set it..

btw - manage to resize it using this website> http://www.resizeyourimage.com/...

p/s: this is just the beginning.. currently beneath my bed is cluttered with 3 other faulty panels awaiting my attention.. or they can be great nests for insects to mate & form a colony.. hehe..