HP 2159m Dead, no power

[budm]

Re: HP 2159m Dead, no power

Do you have good pictures of the main board? It can be as simple as bad voltage regulator.

[ckgbmd]

Re: HP 2159m Dead, no power

Here they are. Is the voltage regulator on the main board? I thought all that stuff was on the power supply.

[ckgbmd]

Re: HP 2159m Dead, no power

Also, I have measured the voltage across the main cap, it is 164 V, so it seems the power supply is fine. If only I could figure out how to turn it on/off with the pin, then I could test the output voltage to the 750 V DC outs to see if those are working. But for now I guess it seems like the problem is with the main board.

[selldoor]

Re: HP 2159m Dead, no power

The Voltage regulators are probably the components with "U" numbers.
There are 2 3 legged ones and maybe some others. The 8 legged ones maybe regulators but not always.
You/we need to know what is written on them.

Read This
https://www.badcaps.net/forum/showthread.php?p=261329 (by retiredcaps.

[Mr Bill]

Re: HP 2159m Dead, no power

Did you fiddle with the on/off button? I did have 1 monitor that the button was bad. It would turn on but you had to press it several times very hard.

[ckgbmd]

Re: HP 2159m Dead, no power

Wow, that is a useful and serious document.

here's what I've got:

U201
MT1117
3.31002M
first lead - 0.0 V
second lead - 1.523 V
third lead - 5.269 V


U202
AX1117
A-18
943A
first lead - 0.0 V
second lead - 1.805 V
third lead - 5.081 V


The best I can tell, these are fixed VRs for 3.3 and 1.8 Volts. the first one appears to be bad? The model lettering is confusing, however, I am not sure I looked at the right data sheet, and I could not find direct correspondence on the data sheet anyway.

[ckgbmd]

Re: HP 2159m Dead, no power

MrBill, my 2 year old did that, repeatedly, but I tested the button and it seems to be working fine - when I press it, the leads are shorted.

[budm]

Re: HP 2159m Dead, no power

U201 IS 3.3 fixed regulator, you only getting 1.523V, so that is bad.
U202 is a fixed 1.8V regulator, it is OK.
Check or replace that C214 next to it.

3.3V fixed:
http://www.digikey.com/product-detai...OSCT-ND/660708

[selldoor]

Re: HP 2159m Dead, no power

Wow, that is a useful and serious document.

here's what I've got:

U201
MT1117
3.31002M
first lead - 0.0 V
second lead - 1.523 V
third lead - 5.269 V


U202
AX1117
A-18
943A
first lead - 0.0 V
second lead - 1.805 V
third lead - 5.081 V


The best I can tell, these are fixed VRs for 3.3 and 1.8 Volts. the first one appears to be bad? The model lettering is confusing, however, I am not sure I looked at the right data sheet, and I could not find direct correspondence on the data sheet anyway.

I can't see any adjusting resistors so yes ,they are fixed and U201 appears to be bad. I say appears as sometimes it can be a knock on effect from
an attached faulty capacitor.

[ckgbmd]

Re: HP 2159m Dead, no power

Thanks. I am trying to figure out if I can test the capacitor C214 without removing it from the board. If it were shorted I would get low resistance across it right? I get 0.8 kOhm right now. That is probably just from some resistor in parallel with it right? It looks OK? God help me replace that VR, not so quick with a soldering iron, I was really hoping it was a cap somewhere.

[retiredcaps]

Re: HP 2159m Dead, no power

God help me replace that VR, not so quick with a soldering iron, I was really hoping it was a cap somewhere.

I use a non temperature heat gun on low to remove SMD components. It takes about 30 seconds to remove. I use kapton tape to protect the components around it so they don't get heated.

The how to test a voltage regulator thread also points to a video by norcal715 that demos how to remove a voltage regulator with a soldering iron.

[budm]

Re: HP 2159m Dead, no power

It will be easy to remove the old regulator by cutting off the two small legs first, no need to try to save the old bad regulator in one piece, best not to damage the board.

[ckgbmd]

Re: HP 2159m Dead, no power

Thank you all very much for the advice. I ordered several VRs (because I will probably destroy one) and also a replacement capacitor for C214 just in case. That one is a CapXon SJ 105C, 100 uF 16V. I looked up the data sheet to get the ripple current rating, and there was some confusion becuase the 6.3 x 7 mm dimension only goes to 68 uF for a 16V piece. So in the end I ordered this
http://www.digikey.com/product-detai...271-ND/1970522
which is a Nichicon rated for 5000 hr (excessive, maybe) and with a 163 mA ripple current rating. But, its OK if the ripple current rating is higher than previously, right?

[ckgbmd]

Re: HP 2159m Dead, no power

Hello, I managed to replace the VR and now I get the correct voltage. Now the power LED started working. I put it 1/2 way back together and the monitor turns on, shows menus etc. The problem is, the image is fuzzy. tiny green dashes dart horizontaly across the screen. Has anyone run into this problem? I suspect the thin ribbon cable that connects to the flat panel, the connectors are crappy. Or maybe it was my hack soldering job? I am also currently missing a couple of the screws that held the boards in place, need to find those. Any suggestions?

[ckgbmd]

Re: HP 2159m Dead, no power

Issue seems to be resolved, mostly:

1. I made sure all screws were in place so grounding was properly done.

2. The ribbon cable connector on the LCD side was bent, I bent it back. It was really a bad connector. Some HP exec saved some $$$. I am attaching a picture of the connector so others may watch out for it. It is a simple slide-in thing, there is no wedge or lock of any kind, thus it is held on with a piece of tape. The tape in the pic is OEM, not mine.

Thank you all for your help.

[ttt9090]

Re: HP 2159m Dead, no power

ckgbmd, I did one not long ago (different make & model) & experienced similar weirdness when I powered it on at first.
Moved it away from PC and connected it to a laptop & it was fine. Moved it back to PC & connected it & was then fine.
Not sure what caused it, but it's good now.
P.S.
Thanks for the post, I am helping a friend to diagnose same monitor now & I believe this will help him

[paul112333]

Re: HP 2159m Dead, no power

hello, i got almost same problem, monitor hp 2159m , powers up for 2 seconds shows screen and after 2 seconds black screen. maybe someones know how to fix it, i check all capacitors but they all good.

[selldoor]

Re: HP 2159m Dead, no power

Picture is just a thumbnail -please post it using manage attachments.
Pic should be less then 2 mb jpg.
You need to read the 2 seconds to black guide by retired caps - click on troubleshooting computer displays at the top of the page - it is a sticky at the front of the forum
Start on post 19

Looking again pic doesnt look clear enought for troubleshooting
it should be straight on and all in focus. One of the back is needed as well

[paul112333]

Re: HP 2159m Dead, no power

when display goes off after 2 secs , i can see with flash light screen still shows. looks like backlight problem.

[selldoor]

Re: HP 2159m Dead, no power

You might well be right -can you post a good picture of the front and back of the board and I will tell you where to test the inverter transformers. From the tiny pic we have 'it looks different to the boards earlier in the thread