Monitor flashing on and off even when not connected to a laptop

[rajc22]

hi,

I have a Pavilion 22xw monitor (over 5 years old) which flashes on and off when solely connected to a power supply. When I connect it to a laptop, the monitor shows the display from the laptop for a second or so and then switches off and on again. I recently connected to a Windows laptop and the monitor stabilised for a few hours but then started flashing on and off again. Hence it does not seem to be a software issue (as Windows and a Mac have both been tested). If it's a hardware issue, is there any way to identify what the problem could be? Some websites suggest a capacitor may be blown but then it did work for a few hours on a Windows laptop.. any help to find out how to identify what the culprit might be would be much appreciated.

Thanks

rajc22 

[savvy2]

Pavilion 22xw monitor (as old as 2014) 7 years old possible, and not fail like pre 2010  love to do.

is a  bad monitor or its cables are bad.

fails on 2PC so is not 2 bad PC  is it,? no.

so bad mon, it is or?

or its cable. bent pins on end of cable are possible

so testing 1,2,3.?

the monitor with no PC present.

turn  MON on and under 15seconds push the OSD menu key first.

see that menu does it work? , at all times and for sure on  any working PC

if not the monitor is bad, OSD must work until the mon power lamp goes amber (sleep)

if mon sleeps as the all do not connected to a PC, cycle power on mon, do Menu button again,.

you said

flashes on and off when solely connected to a power supply.

does that mean no PC connected and power lamp button flashes

the screen flashes I can not see over your shoulders so, I may answer wrong , never in person me. hands on.,

please tell what flashing means, be very clear on that.

or answers will be wrong, from me too.

I  repaired actual monitors (inside) back to 1965, (even huge military RADAR systems and the for DEC VT100s later.)

and more  until 80s, so know my way round the trees. (using I2C testing too)

but what matters here her is what you see and is not clear to me a tall

forget caps you have no soldering iron ,solder or skills to do that . 

focus first on testing the monitor and its cable first.

'then we let the chips fall as the must.

the monitor is bad.

you know that, but what part of it is bad is still unkown.

what is flashing mean? where even show photos of it failing

ALL monitors made in 20 + years all go to sleep , when PC goes dead or sleep or the cable falls off the monitor.

either.

it will tell you GOING to sleep, or power saver mode or  lost connections or show, in 15 seconds time.

lost data from PC.

the menu button must be pushed 15 seconds or less from monitor turned on

if you say the PC fail, and whatever flashed IDK you'd cycle the monitors  power first.

then see what it tells you, if nothing on the screen the MONITOR IS FOR SURE DEAD or its power pack dead.

how is that for testing, I can go as deep as you are brave, 

[rajc22]

Many thanks Savvy2 for your reply 

I will try to answer as best I can 

does that mean no PC connected and power lamp button flashes Correct - flashes whether PC is connected to a laptop or not  

the screen flashes I can not see over your shoulders so, I may answer wrong , never in person me. hands on.,

please tell what flashing means, be very clear on that. The whole screen comes on and then comes off similar to when the power comes on and then switches off and then comes on again. The power button switches off each time also 

or answers will be wrong, from me too.

I cannot press the OSD button within the 15 seconds as the power goes off and then comes on again every second or so hence insufficient time for the button effect to be observed before power goes off again and flashes. 

ALL monitors made in 20 + years all go to sleep , when PC goes dead or sleep or the cable falls off the monitor.

either. I don't think the monitor is going to sleep; it seems like inconsistent power supply causing it to shut off but then restart again every second. 

For a short period (a few hours) yesterday the monitor when connected to my laptop worked fine and I was able to press the OSD button, do a factory reset etc.. but it made no difference. The flashing started again early today. It really seems like the power is going off each time and then coming on again.

Unfortunately i cannot upload videos onto this forum but i attach a picture below 

I did actually remove the circuit board to see if the capacitors had blown but they look fine.. (from a pure amateur perspective and following guidance from a YouTube video).