Hi guys. I am very new to this, but was hoping you would help me fix my lcd. Originally, the screen started to turn itself off randomly. I was able to restart it, but after few days it shut down and I was not able to bring it back to life. I replaced all 25V 470 uF caps on this board. They were not blown, but looked like they were starting to "inflate". (sorry, i am not sure what the proper terminology is to describe it). That did not fix the problem though. When I connect the power cable I can hear a clicking noise coming from the parts that I circled on the picture. They turn really hot if the power cable is connected. Would someone please tell me what I should do next? How do I go about testing the other components on the board? Thank you.
HP lcd L1502 15"
Collapse
X
-
Re: HP lcd L1502 15"
Hi did you test the transistors that you have arrowed (probably 5707 or 5706 markings on them )
Also did you resolder the 4 x transformers
If you check threads that deal with Dell 172 monitors they have the same type of board and have the same symptoms -
Re: HP lcd L1502 15"
Hi guys. I am very new to this, but was hoping you would help me fix my lcd. Originally, the screen started to turn itself off randomly. I was able to restart it, but after few days it shut down and I was not able to bring it back to life. I replaced all 25V 470 uF caps on this board. They were not blown, but looked like they were starting to "inflate". (sorry, i am not sure what the proper terminology is to describe it). That did not fix the problem though. When I connect the power cable I can hear a clicking noise coming from the parts that I circled on the picture. They turn really hot if the power cable is connected. Would someone please tell me what I should do next? How do I go about testing the other components on the board? Thank you.
What brand and series capacitors did you use as replacements for the bulging caps?
PlainBillFor a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.
Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.Comment
-
Re: HP lcd L1502 15"
Hi sabre, Thank you for replying to my post. I appreciate your help. The transistors are 5707. How do I go about testing them? I have very limited understanding of these things. I did not resolder the transformers.Comment
-
Re: HP lcd L1502 15"
Hi PlainBill,
Thanx for taking time to look into this for me. I used united chemi-con caps from Digi-key.
Also, I found out that the problem occurs when I connect little circuit board that has VGA connector on it. If its not connected, there is no clicking heard on the big board.Comment
-
Re: HP lcd L1502 15"
That's the logic board. It's kinda obvious that it won't do it without the logic board connected, since the logic is what instructs the inverter to turn on.Originally posted by PeteS in CARemember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.Comment
-
Re: HP lcd L1502 15"
Yes. Your problem is in the inverter area. For now, take out the 5707 transistors and measure them with your multimeter set to 200 ohm scale. If any leg combinations read 0 ohms the transistors are bad and need to be replaced.Originally posted by PeteS in CARemember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.Comment
-
--- 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.
--- end sig file ---Comment
-
Re: HP lcd L1502 15"
Hi Retiredcaps,
I've read that you do that, but I don't know how to test it. I am going to read about it and try testing it right now.
Thanx for advice. I appreciate it.Comment
-
Re: HP lcd L1502 15"
So here is the pic of the transistors i need to test. How do I go about testing them? I tried setting my meter to 200 ohms. When i connect positive lead to B and negative to E or C i get random readings that stabilize around 0.9-8. If I test from E to B and from C to E i just get random readings that do not stabilize. I am not sure if I am doing this right. Thank you for putting up with me. Any help would be appreciated.
leoComment
-
Re: HP lcd L1502 15"
So here is the pic of the transistors i need to test. How do I go about testing them? I tried setting my meter to 200 ohms. When i connect positive lead to B and negative to E or C i get random readings that stabilize around 0.9-8. If I test from E to B and from C to E i just get random readings that do not stabilize. I am not sure if I am doing this right. Thank you for putting up with me. Any help would be appreciated.
leo
Please attach a picture of your meter with the function switch set in the position you are using, and with the probes plugged in..
PlainBillFor a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.
Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.Comment
-
Re: HP lcd L1502 15"
OK here are the pics of my meter:Last edited by leov; 03-12-2011, 10:36 PM.Comment
-
Re: HP lcd L1502 15"
I can't explain the strange behavior. Ordinarily I would expect to see this display between any two legs of a transistor. A jitter of the last digit isn't unusual. What reading do you get when you try to measure the resistance between two points on the circuit board that are obviously connected, for example, the emitter of the two transistors in post 12?
PlainBillLast edited by PlainBill; 03-13-2011, 07:04 AM.For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.
Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.Comment
-
Re: HP lcd L1502 15"
So here is the pic of the transistors i need to test. How do I go about testing them? I tried setting my meter to 200 ohms. When i connect positive lead to B and negative to E or C i get random readings that stabilize around 0.9-8. If I test from E to B and from C to E i just get random readings that do not stabilize. I am not sure if I am doing this right. Thank you for putting up with me. Any help would be appreciated.
leo
Don't forget to read PlainBill's above post.Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!Comment
-
Re: HP lcd L1502 15"
The readings your getting with your ohmmeter, the jumping and taking time to settle down makes me wonder if you may have a problem with your DMM leads?What reading do you get on the 200 ohm scale with the leads of your meter hooked together?
Don't forget to read PlainBill's above post.Comment
-
Re: HP lcd L1502 15"
You definitely have the meter set to the correct range, and the leads plugged in correctly for resistance measurements. The display shows a typical display for a resistance greater than 200 ohms.
I can't explain the strange behavior. Ordinarily I would expect to see this display between any two legs of a transistor. A jitter of the last digit isn't unusual. What reading do you get when you try to measure the resistance between two points on the circuit board that are obviously connected, for example, the emitter of the two transistors in post 12?
PlainBill
Thank you for your help guys.
leoComment
-
Re: HP lcd L1502 15"
Bill, here is what i did. I think that I found the bad transistors. Please see the picture. Th3 has pointed me to those before, but with everyone's help and a little of reading here on the forum i think i got it. Please confirm my findings.
Thank you for your help guys.
leo
PlainBillFor a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.
Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.Comment
Related Topics
Collapse
-
by B0r1sPSU - BN44-00878A
Symptoms:
The TV turned itself off, and I haven't been able to turn it back on. The standby voltage was unstable and lower than it should be.
A weak clicking sound was coming from the transformer.
Video with clicking sound:https://www.youtube.com/watch?v=lAduhjNtqCA
Progress:
After the transformer, I measured four Schottky diodes. DM862C and DM864C diodes readings were 003 in both directions. After detaching them from the circuit and measuring them, DM864C was the shorted one. These Schottky diodes are SB550.I... -
by slimmy182Hello, I bought this Mac from a friend, he said that it simply stop working. The MacBook looks very clean but does not power on, stuck on 5v 0.42A, and sometimes display 5V and 0A (then 0.071A and again 0A).
I opened it looking for some problem, it was not touched before for sure and the board is very clena, no spot of corrosion at all from what I can see. Voltage on multimeter of the board off the case it's the same, 5V 0.42A. But then I noticed this "clicking sound" come from the board ( I attached here the audio file).
Looking on google I found this:... -
by beetle1303I gotten a Carver CM-1090 amplifier from a friend who has kept it in storage for decades. Opened it up, thick layer of dust cumulated everywhere. Vacuumed it semi-cleaned, and blown off as much as possible the remaining dust. This is a 220V version.
On initial powered up with nothing connected - it works with all the lights and button indicator lit up as pressed, etc. I then powered off, connected a CD player into the CD RCA input and powered it on. It seemed to work for a short while and when I turned the volume up and down to see the the VUs works, the power started to clicked off...3 Photos-
Channel: Troubleshooting Audio Equipment
-
-
by mikelu53I have a UN60D8000YF with a BN44-0432A power supply and a BN41-01622C main board.
The set was working then not,then started clicking.
Wilth the power supply disconnected from the main board I can occasionally get it to power the LED back lights , getting it to stop clicking is luck.
Checked caps and diodes and mosfets the best I could. When it stop clicking there is 5v and 18v on the connector to the main board.
A schematic or suggestion would be great.
Thanks -
by bffargoLG 60PB66550 NOV 2014
PSU: EAY63168603
PCB: EAX65359531 2013.11.01 Rev:1.0
Main board: EAX65399305(1.0) 13.11.27 PU42A/PA42A/PD42A
Symptom:
While watching, just went black and started clicking relay every few seconds.
Initial diagnosis:
Removing JUST the main CPU/Input PCB from circuit stops the clicking. No problems with any other boards/drivers. (Removing all other boards and only putting Main back in is all it takes to start clicking again)
Deeper diagnosis:
Pulling pins #1/#2 (Blue/Grey) from the connector housing... - Loading...
- No more items.
Comment