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.
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.
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.
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.
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.
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.
--- begin sig file ---
If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.
We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.
Please do not post inline and offsite as they slow down the loading of pages.
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.
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?
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?
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.
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
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.
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
Last edited by selldoor; 01-11-2014, 07:54 AM.
Reason: pics
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
hi all, got this macbook with dead trackpad. after some investigation i found that fuse is bwlown. it's marked with a K on it. anyone kjnow it's value ? it is a 0402 package.
another problem is: i tried another trackpad that was working fine, but the feedback sensor was not. all volts are present, but the click mechanism isnt .
Step 1.
Laptop was brought to me as dead not working. Removed everything , cleared everything.
Step 2.
Some liquid damage close to the Type - C connector, and the connector even though it was cleaned wasn't charging the battery . Removed the Type-C port, and replaced it. Now the laptop turns on and charges battery. Shows external screen , not internal.
Step 3.
Took out the screen and checked it to a secondary Gen 2 i have, screen works like a charm.
Step 4.
Lets ,dive into the board. I see the edp cable on the...
Before replacing what I know to be bad even with my novice experience. What I have checked at the moment is the fuse and the obvious burnt capacitor. I haven't bought any replacement parts yet.
I still have no idea how this happened but could just be plain old turned bad. What other stuff should I consider buying as replacement? thanks in advance.
Edit: I saw that a replacement board can be had for about $50. I would rather attempt to fix before just replacement the board.
Hi I wonder if anyone might be able to steer me in the right direction. I have this Samsung UE46ES8000 TV and it went bang during use. The main fuse on the PSU board is open. I've checked every diode/mosfet/transistor I can see and nothing appears to be short to cause the fuse to go. The DC output of the bridge rectifier is not short either. I've seen online that some of these models are known for having their PFC mosfet or other mosfets shorting and blowing the fuse but i'm not seeing that here. If anyone aware of these models having any issues to cause this? I'm reluctant to just replace the...
I'm inexperienced with electronics repairs, I've done a little bit of soldering caps and whatnot, but i have a blown fuse on this mimaki printer I got which I have bought a replacement for.
How do I remove this type of fuse (see picture)...it kinda looks like it would pull out of that bracket but it didn't come at first pull and I didn't want to brute force it incase it's soldered on there like most of the rest of the components.
Anybody know how to remove this type of fuse?
(The fuse is toward the bottom of the image labeled F2)...
Comment