HP w2338h LCD Monitor randomly powers off and randomly won't power on.

[cobaltsmith]

Just started having problems with this monitor and not sure why. I have it taken apart and can't see any bad caps. I was hoping someone might have an eye for what's going on better than I.

I can turn it on and it will run fine for random amounts of time. From turning off immediately to waiting half hour. Sometimes it simply won't turn on. Any help would be greatly appreciated. Thank you in advance.

[senndogg]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

what colour is the led indicator when it does not want to turn on?

[cobaltsmith]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

Amber? I'm honestly not entirely sure. I did the power tests some time ago and only recently pulled it back out to check for bad caps and what have you. I heard about some retarded power mode where it won't turn on. I made sure that wasn't the issue.

[selldoor]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

Hi - Good set of pictures thanks -Can we have similar for the backs of the boards if possible without the flash.
Intermittant problems are often difficult to bottom. Whilst the caps may not be bulged or leaky most seem to be ELITE which are not considered great, particularly on Power Supply. - Are they all elite?. If no -one can spot anything else perhaps consider a recap - if it runs hot they may be dried out.
There are a number of these coming up where the ccfls are broken - they may be extra brittle so suggest you handle panel with care. Also there has been some with burning/ arcing reported at the ccfl end wiring - you could check for this - maybe triggering a protection circuit and shutting it off . Perhaps Senndogg was working on that theory - if the power light stays the same colour and just the screen seems to go off it could be the backlights. When it is in that state can you see any image of what is on the pc - perhaps by shining a flashlight at the screen at different angles

[cobaltsmith]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

I know it isn't the backlight. The power switch does change color as the monitor shuts off. I will get the back of the boards posted shortly.

[cobaltsmith]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

Backs of the boards.

2088 is the logic board. 2089 is the power board.

[selldoor]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

Next time it is all connected and working measure the voltages on the power out socket on the power supply board. When it goes off measure again and post the results.

[cobaltsmith]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

I do not have a voltage reader. Sorry I forgot to mention that. I repair 360s so I have basic tools. No meters I'm afraid.

[selldoor]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

Well I dont think you can do much more without one
they have $5 multimeters at harbor freight tools in america

[senndogg]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

@selldoor: in fact i have had a similar issue with a hp monitor, when plugged in the mains; led was amber and pressing the power button had no effect. sometimes it started ok. it was an easy fix: caps in the 5V rail.

[cobaltsmith]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

@selldoor: in fact i have had a similar issue with a hp monitor, when plugged in the mains; led was amber and pressing the power button had no effect. sometimes it started ok. it was an easy fix: caps in the 5V rail.

Could you direct me to those caps? They arn't very expensive or hard to replace.

[senndogg]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

it was a different board but at yours seem to be the C915 and C939 in the power board.

[cobaltsmith]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

Thanks very much. I found a complete cap replacement kit on Ebay for 13. I'm going to hook everything up one more time and check for shorts while it's powered up. I found a black mark in the casing that looks like a short. SO I think selldoor was on to something when he talked about the safety being tripped. That really sounds like the behavior it was showing.

Course, your description is just as valid really. So, both will be tended to. I really appreciate the help guys.

[selldoor]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

Make sure the Ebay site is selling decent caps REAL panasonic rubycon nichicon etc otherwise it may be a waste of money. Try and cost making up your own set from digikey.

[cobaltsmith]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

Woh. Went to Digikey. Little overwhelming on what they have available. However in their listing it states high quality Caps and notes the same names you mentioned. Here is the link. http://www.ebay.com/itm/Repair-Kit-H...ht_4512wt_1163

I can't do the testing today due to some school things going on with my kids. Hopefully I can test and fix or order tomorrow.

[selldoor]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

OK digikey can be a bit daunting 200,000 caps to choose from but It gets a lot easier
In the search type capacitors
Then choose aluminium
In the first column highlight FR
Manufacturer column highlight Panasonic

Click apply filters

You then just enter the voltage and Uf value off the cap
This will give you a couple of choices to do with the type of packaging - you want the one where you can order 1.

Check the physical size is the same or smaller.
If they dont have FR try FM Then FC.

Having said that your chap says they are good brands and he is in the US not China - feedback good and 7 day moneyback.

[retiredcaps]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

See (regulars may skip URL below)

https://www.badcaps.net/forum/showpo...4&postcount=19

Fastest way is to check "in stock" and then type in the search field

1500uf 35v fr

if you are looking for a 1500uF 35V FR cap.

[retiredcaps]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

Having said that your chap says they are good brands and he is in the US not China - feedback good and 7 day moneyback.

I believe budm knows the seller.

[klkmalik]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

Just started having problems with this monitor and not sure why. I have it taken apart and can't see any bad caps. I was hoping someone might have an eye for what's going on better than I.

I can turn it on and it will run fine for random amounts of time. From turning off immediately to waiting half hour. Sometimes it simply won't turn on. Any help would be greatly appreciated. Thank you in advance.

Did you try resolder high voltage area,? such as invertor tranformer , ccfl and ballast caps.

[cobaltsmith]

Re: HP w2338h LCD Monitor randomly powers off and randomly won't power on.

Did you try resolder high voltage area,? such as invertor tranformer , ccfl and ballast caps.

You know, I honestly didn't even think to check the solder conns. I have ReFlowed so many xbox 360's and this didn't occur to me. Good idea. I will double check that stuff when I get a chance to. Thank you very much for the idea.