compaq q2159 going into standby

[jwilliams1967]

Hi everyone. This is my first post so I apologise if Im in the wrong forum.
The problem I have is this monitor only displays a picture when I first power it on and then when it boots into windows. The picture lasts for a second then goes black. if I switch off and on again I get a picture for a second then if goes off again. the same happens if I unplug the vga cable. there is no picture at all so I think the 2 seconds to black is not the problem. I have visually checked for bad caps and dry joints . I have followed the 2 seconds to black as described in this forum although ,as I have stated , I don't think this is the problem because I have no picture at all. please help.
many thanks

[Rtech]

Re: compaq q2159 going into standby

If you get a Picture and then it goes off, the two most likely faults are the Backlights,be it the lamps or the wiring on one of them or more...OR a failed Inverter transformer.Photos are the 1st requirement for more help...use 'Go advanced ' below then manage attachments.

[rauno45]

Re: compaq q2159 going into standby

When my benq monitor showed similar symptoms it turned out to be one of the transistors shorted and because of that the power supply shut itself down after a few seconds so that it could not hurt any other components on the board. Maybe you should check for shorts on the board. But if you would have pictures it would help to troubleshoot a bit.

[jwilliams1967]

Re: compaq q2159 going into standby

will post pics in a minute

[jwilliams1967]

Re: compaq q2159 going into standby

Here are the photos as requested. I have followed the guide 2 seconds to black to the best of my ability but as I have stated ,I don't think its relevant because I cannot see a picture when I shine a light on the screen. ( im a computer engineer and have seen inverter problems many times before).
If the monitor is left on for a while then the screen goes into standby as would be expected . strangely every time I shut the pc down and restart I get a brief picture at the startup screen and also when it first boots into windows. I have tried this monitor on other pcs so am certain its not a pc issue.

please help people .

[philliesfan30m]

Re: compaq q2159 going into standby

i'm gonna have to agree with rtech as it being a bad bulb probably sending it into shut down mode or inverter problem. what voltages do you have on the 10 pin connector on the power board with power on and off?

[jwilliams1967]

Re: compaq q2159 going into standby

thanks for the quick response . will check in the morning and post results.

[Davi.p]

Re: compaq q2159 going into standby

I've never heard this type of problem, it always hear one new..
Check the voltage of the 2 voltage reg. U101-U102 on video input board, report the part. numb. and pin readings.

[jwilliams1967]

Re: compaq q2159 going into standby

Hi guys . im a bit of a novice so can you give me some quick guidance please
When measuring the voltage on the 0 pin connector what should I set my multimeter too ? ac or dc and what range ? and can I use the metal chassis as an earth reference point or would one of the black wires on the terminal be earth. many thanks for your patience

[jwilliams1967]

Re: compaq q2159 going into standby

worked it out people . set meter to 20v dc and last 2 blacks are earth . will post results as requested by philliesfan0m

[jwilliams1967]

Re: compaq q2159 going into standby

hi here are the results from the 10 pin connector working from the red wires down to the green on and in standby.

monitor on
5.06
5.05
0
0
3.6
2.83
3.21
2.53
2.48
0

monitor in standby
5.06
5.05
0
0
0.09
3.03
2.51
2.48
2.48
0

hope this makes sense to somebody.
thanks again

[philliesfan30m]

Re: compaq q2159 going into standby

what are all the pins labeled on the board if they are labeled. pin 5 looks to be the ps_on signal from the main board.

[Lumberjack777]

Re: compaq q2159 going into standby

With your symptoms and not being able to see a picture at all. I'd check the voltage regulators on that main board.

Retiredcaps wrote an excellent guide on how to test those. https://www.badcaps.net/forum/showth...tage+regulator

Also, this youtube is excellent from norcal715 - http://www.youtube.com/watch?v=cNFzBJELFoU

[Rtech]

Re: compaq q2159 going into standby

When you have these symptoms,and carried out the '2 secs to Black',you decided that this was not the problem, as you could not see any image on the screen.....in some cases that is quite normal,but still the problem is '2 secs to black'. You can switch it on and off ?? you do get an initial image ?? it looks from your voltage readings that the 5v is fine, and if the on/off voltage eluded to by Philliesfan is the Enable/Backlight On,then in my opinion the problem is on the power supply Board or Backlights/Backlight wiring.

[Davi.p]

Re: compaq q2159 going into standby

Your pin readings seems correct, what do you get on that "not connected" 11th and 12th pin visible on the bottom side?

[jwilliams1967]

Re: compaq q2159 going into standby

hi davi.p can you tell me exactly where 11th 2th connectors are please

[jwilliams1967]

Re: compaq q2159 going into standby

Here are the results from metering the voltage regulators.
pin 1 is labelled on the board

U101 LD 1117A 33AVE
pin1 0
pin2 3.27
pin3 5.06

U102 AS 1117L-18
pin1 0
pin2 1.79
pin3 3.26

thanks for all your help people. learning a lot and enjoying it

[Davi.p]

Re: compaq q2159 going into standby

the first readings you've made are on the output connector, if you watch on the bottom side there are 2 contacts for the same connector made for a larger connector, at the 11th + 12h pin you have to measure something from 12 to 24 v, but this don't reveal much i think. I notoce now that in the title you said "goint to st.by" why? Unfortunately your Video input board (VIB) has good regulators, so i think you have a bad vib.

[jwilliams1967]

Re: compaq q2159 going into standby

the monitor goes into standby because of power management settings . it is behaving as it should but has no display or backlight. what is vib?

[jwilliams1967]

Re: compaq q2159 going into standby

sorry ignore last question