HP 1955 19inch Monitor troubleshooting flickering backlight nothing else displayed

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I would like to start off by saying thank you to the members of this forum, you guys have helped me a couple times fixing my Dell E172FP LCD monitor. but this time i have a problem that i searched the forums for but didnt find anything.

HP1955 LCD monitor when you plug it in it flickers the black light with a clicking sound coming from the back. the power button and all controls on the front do not do anything there is no sign of an image from the incoming connection. ive been told its the Logic board does this sound right. i ask because there are 3 bulged caps on the power board or is it the caps?

Any help would be appreciated..thanks
Chris

[PCBONEZ]

Re: HP 1955 19inch Monitor troubleshooting flickering backlight nothing else displayed

The caps may not be the whole problem but you aren't going to get anywhere with bad caps in it.
You should replace the caps first and then see what it does with good caps.
You just might get lucky and that's all it needs.

HP screens are often built by someone else.
If you look at the markings on the PCB's and do a little googling you may be able to figure out who built it and then look for problems with their other products.

.

[Krankshaft]

Re: HP 1955 19inch Monitor troubleshooting flickering backlight nothing else displayed

That HP 1955 is a Benq build (it's silkscreened right on the PSU ) and has the same design problems as the Benq FP737s the C5707 issues.

Let me guess the bulgers are Elite caps ?

Check the C5707 transistors while your at it also check the pico fuse (on mine it was 5 amps) and if it is shorted most likely one of the C5707s is dead.

You may be lucky with the caps as PC said.

A ticking sound usually means that the PSU is cycling probably due to the bad caps.

If your monitor powers up after cap replacement hit the power switch on the front panel to shut the monitor down to make sure that both backlights go off. If not thats another discussion.

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Re: HP 1955 19inch Monitor troubleshooting flickering backlight nothing else displayed

That HP 1955 is a Benq build (it's silkscreened right on the PSU ) and has the same design problems as the Benq FP737s the C5707 issues.

Let me guess the bulgers are Elite caps ?

Check the C5707 transistors while your at it also check the pico fuse (on mine it was 5 amps) and if it is shorted most likely one of the C5707s is dead.

You may be lucky with the caps as PC said.

A ticking sound usually means that the PSU is cycling probably due to the bad caps.

If your monitor powers up after cap replacement hit the power switch on the front panel to shut the monitor down to make sure that both backlights go off. If not thats another discussion.

WOW are you psychic? they are Elite caps!!

ive read alot of people have had issues with these caps. are the ones at Radio Shack for example a decent one to use or would i be better off getting something else.

Thanks..

[Wizard]

Re: HP 1955 19inch Monitor troubleshooting flickering backlight nothing else displayed

Order caps from king or badcaps.net or your electronic suppliers as recommended here.

Stick to caps we listed here in the what kind to get faq section of this forum.

Cheers, Wizard

[PCBONEZ]

Re: HP 1955 19inch Monitor troubleshooting flickering backlight nothing else displayed

WOW are you psychic? they are Elite caps!!

ive read alot of people have had issues with these caps. are the ones at Radio Shack for example a decent one to use or would i be better off getting something else.

Thanks..

Radioshack caps are not suitable.
Radioshack does not have low ESR caps and I think they only have 85 C temp caps.
You should stick with 105 C rated caps. [Just a good idea.]

As to what is needed it depends on the series[model] the Elite caps are.
For Elite in LCD's I've seen EB and PF series'. [There are probably others used.]

Elite EB ideally should be replaced with something like FM, MBZ, FJ, WG.
The PF aren't really even low ESR and FC or PW are fine there.

.

[PCBONEZ]

Re: HP 1955 19inch Monitor troubleshooting flickering backlight nothing else displayed

If you are in the US then FC or FM are at digikey.com
MBZ (or MCZ maybe) you can get from badcaps.net.

[EGuevarae]

Re: HP 1955 19inch Monitor troubleshooting flickering backlight nothing else displayed

If your monitor powers up after cap replacement hit the power switch on the front panel to shut the monitor down to make sure that both backlights go off. If not thats another discussion.

I have a Samsung 173s that at irst didn't want to display anything. Then I replaced a cap per PCBONEZ suggestion, and there was image... but now the lamps won't turn off even without power (well, I mean, with the monitor in soft-off...). Any idea?

[PCBONEZ]

Re: HP 1955 19inch Monitor troubleshooting flickering backlight nothing else displayed

I am interest to know that too Krankshaft.
I haven't run into that one yet.