MrFlibbles' Viewsonic VX2835WM Problem

[retiredcaps]

Re: MrFlibbles' Viewsonic VX2835WM Problem

PS For my ongoing education there is a Panasonic with same # with a "B" at the end. What does the "B" signify?

I believe it stands for "bulk". That is, minimum order is 500 or 1,000 caps at one time.

[MrFlibble4747]

Re: MrFlibbles' Viewsonic VX2835WM Problem

Thanks guys. I got my Panasonic # wrong as I skipped a row when looking along the reference table........

I was referencing the Oz Element14 site so will go for Panasonic (EEU-FM1C471)/Rubycons depending on availability. Should have them later today.

PS For my ongoing education there is a Panasonic with same # with a "B" at the end. What does the "B" signify?

Well got the replacement caps and soldered them in.
Powered the boards up and screen flickered backlight led's flickered for a few seconds then something went "phuttt" and now there is no power to the main board at 5V SB but 5v still present at power board (did not get chance to 5B SB before something blew. Examined main board but no sign of anything blowing. Totally lost now.........

[retiredcaps]

Re: MrFlibbles' Viewsonic VX2835WM Problem

Examined main board but no sign of anything blowing. Totally lost now.........

1) Did you check your work for any solder bridges?

2) Did you put the caps in the right way? They have polarity.

3) Post a picture both sides of the main board with the replacement caps.

[pete_nz]

Re: MrFlibbles' Viewsonic VX2835WM Problem

I'm actually at the same point as MrFibbles. I measured all the caps on the power board and I know for sure some of the caps are dead. I have ordered a cap replacement kit so will post back when I get them in.

Also when I turned on the power after changing C124 and C126, it flickered for a bit and actually turned on with a picture but once I pulled the plug it will now only show a black screen with the backlight still on.

[MrFlibble4747]

Re: MrFlibbles' Viewsonic VX2835WM Problem

1) Did you check your work for any solder bridges?

2) Did you put the caps in the right way? They have polarity.

3) Post a picture both sides of the main board with the replacement caps.

Caps are on correctly for polarity.
Soldering is not pretty but not too untidy, no evidence of bridging. I cleaned the board after soldering and inspected it closely before testing.

Given my testing unit (details posted previously) how would I set it up to check for dead caps?

Will get pics later as I'm at work now (lunch time).

[pete_nz]

Re: MrFlibbles' Viewsonic VX2835WM Problem

Sorry to interrupt this thread again but I was thinking about adding a fan to the power and logic board casing. I'm fairly sure this fan can fit between the two boards

http://www.coolermaster-usa.com/prod...roduct_id=2978

So the question is will it be ok to tap into the 12V or 5V (slower speed in case the noise is to high)? If so what are the safest points to tap into?

[t.j.]

Re: MrFlibbles' Viewsonic VX2835WM Problem

Found a resistor that look like it was pushed out, had one visible broken trace! the top black box i know it just runs to the diode to the left, the bottom black box! not sure of trace route as board a bit ugly an not really visible signs of trace~do both north ends of jr10 an jr11 goto south pole of r125(i think) or just jr11? then does it continue through to r604 west pole? will draw what i think traces are an upload

[pete_nz]

Re: MrFlibbles' Viewsonic VX2835WM Problem

Did a full recap on both boards and the monitor is like new again! I did find a surface mount resistor that looked to be unsoldered but I doubt that was the cause since a few caps were dead/way out of spec. Used Fujitsu solid caps pulled from a dead motherboard and Panasonic FC caps on the logic board and a ebay power board cap kit that were all Nichicon.

Now on to the fan! Can I assume the easiest point to wire to is just the 5V or 12V points on the power board?

[Dusk]

Re: MrFlibbles' Viewsonic VX2835WM Problem

Hi all, first post here, thought it might be better to post in this recent thread rather than start another.

I have a similar problem with my VX2835WM, power LED wont stay lit, screen wont stay lit for more than a fraction of a second and flickers. For the past year or so the monitor would work fine for 6 hours then briefly loose power to the screen, and recover after a couple of seconds.

I am planning to replace the C124 and C126 caps which are the only ones with visible bulges first. It seems like replacing these alone has a low success rate here, and most people fix their problem only after replacing all the caps on both the motherboard and the powerboard, even the small ones.

My question is, where do I buy replacement caps from? Is a local electronics shop (http://www.jaycar.com.au/) going to have most of them? Do I need to go online to a big place like (http://au.element14.com/rubycon/16yx...elatedProducts), or should I buy a premade pack?

And should I try to work out in advance which of the caps are bad, or just buy a complete replacement set from somewhere like http://store.lcdalternatives.com/Rep...P1841492.aspx?

I have a very simple multimeter that does AC/DC voltage/current/resistance.
http://img542.*************/img542/7...1081339501.jpg

[retiredcaps]

Re: MrFlibbles' Viewsonic VX2835WM Problem

My question is, where do I buy replacement caps from?

And should I try to work out in advance which of the caps are bad, or just buy a complete replacement set from somewhere like http://store.lcdalternatives.com/Rep...P1841492.aspx?

You need to buy capacitors that are low ESR for the SMPS power supply. Panasonic makes low ESR caps like FR, FM, and FC ("best" to "entry level"). So choose a supplier that carries the above.

Also the power supply is also found in the Hanns G as I mentioned in post #3. See this megathread

https://www.badcaps.net/forum/showthread.php?t=11329

A kit is not likely to have replacement caps for the logic board and most of them exclude the large filter capacitor.

[Dusk]

Re: MrFlibbles' Viewsonic VX2835WM Problem

I replaced the C124 and C126 caps on the motherboard with cheap equivalents from the local electronics shop, and it improved things!

I almost destroyed the board with my soldering job, I ended up going out and buying a new soldering iron with temp control because the old one was a decade old. Had to use a tiny drill bit to clear one of the PCB holes of metal that wouldn't melt, but it didn't seem to damage the board because it worked when I turned it on.

Now it powers up! It still has some serious issues so a full recap of the power board is definitely required at a later point (I will have to buy a multimeter with capacitance readings), but it is at least usable now.

Thanks.

[Dusk]

Re: MrFlibbles' Viewsonic VX2835WM Problem

Replacing the two caps stated above brought the beast back to life for about two weeks, before it died completely.

I bought a full 12 cap replacement set for the power board. It was much easier de-soldering using the supplied wick. After 3 hours of work, the monitor now lives once again!

Thanks to this amazing community for all the money saved and all the lessons learned.