Re: What bad glue can do to the board
@TechGeek: What did you mean by "IT"?
SolderTrouble
Member
Last Activity: 10-12-2017, 06:10 AM
Joined: 08-20-2013
Location: Silver Spring, Maryland
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Re: What bad glue can do to the board
I found another forum thread about the glue:
[url]http://www.electronicspoint.com/threads/that-awful-yellow-glue-on-circuit-boards.61364/[/url]
The last message there contains: "You can't get it off until it starts discoloring. I've tried."
The glue on my monitor's power supply is still yellow or light tan. I tried applying 91% isopropyl alcohol with a q-tip for a few minutes but that didn't help me scrape it off with an exacto knife. So I'm looking for more detailed information about how to remove the glue....Leave a comment:
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Re: Samsung 2493HM - black screen, blue LED steady on; intermittent
@budm, Thanks for all the time you contributed. Now that my monitor's immediate problem appears to be fixed, I have a dilemma about whether to work on more of the glue or hope it will last years before the next glue-related problem arises.
I did a little more research and found the following forum thread:
[url]http://www.electronicspoint.com/threads/that-awful-yellow-glue-on-circuit-boards.61364/[/url]
The last message there says about the glue: "You can't get it off until it starts...Leave a comment:
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Re: Samsung 2493HM - black screen, blue LED steady on; intermittent
@budm: "Use Alcohol to soften the glues."
I tried putting 91% isopropyl alcohol on a patch of the glue and didn't notice any softening, neither quickly nor after a few minutes of soaking. Can you provide more detailed information about how to remove the glue? If it's going to be very time-consuming or risks damage to the board, leaving most of the glue in place might be the wisest course of action, especially if it's likely to be years before the glue degradation causes another problem. Do you have...Leave a comment:
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Re: Samsung 2493HM - black screen, blue LED steady on; intermittent
I think I've made progress. I video-recorded the bottom of the power supply under dim lighting and recorded the arcing, which showed me exactly where it was arcing. A small transformer is on the top side there. Some of the yellow glue touches the transformer, a neighboring capacitor, and something I'll call an uninsulated jumper wire. Attached are two frames of the video that show the moment the arc begins and the moment of brightest arc. Also attached are three photos: two of the bottom of the power supply with...Leave a comment:
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Re: Samsung 2493HM - black screen, blue LED steady on; intermittent
I've attached 9 photos of the power supply board, which I describe at the end of this message.
I measured the resistance of the yellow glue in several places, including the spot that seemed darkest (tan), by placing the probe tips about 1/10" apart. It was "infinite" each time. It was also infinite in the three spots where I scraped off the glue's surface. Of course, it might conduct at a higher voltage than the multimeter puts out, but hopefully the fact that it has very high resistance...Leave a comment:
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Re: Samsung 2493HM - black screen, blue LED steady on; intermittent
Since it's still yellow, is it unlikely to be the cause of problem?Leave a comment:
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Re: Samsung 2493HM - black screen, blue LED steady on; intermittent
Thanks, budm, for the speedy reply!
By "brown" glue do you mean the yellow glue? Does the glue change color from yellow to brown as it ages, or are there different colors that both age poorly?
EDIT: The thread about bad glue that budm linked says the glue darkens and becomes conductive with age. But the glue on mine is still yellow. Does this mean it's not yet conductive?Last edited by SolderTrouble; 08-03-2016, 03:05 PM.Leave a comment:
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Samsung 2493HM - black screen, blue LED steady on; intermittent
Four days ago my 2493HM didn't wake up when I woke up my computer in the morning. Its screen remained black, and its blue LED was lit (not blinking). Turning it off & on several times didn't help (so I've temporarily swapped in an old 19" monitor). Before it failed I saw no signs of trouble. (Not counting 5 years ago, when it kept failing unless I kept it from sleeping, and while failing made a sound like electrical arcing which sounded like it was somewhere behind the LED. Samsung fixed it for free since it was still under warranty, but they didn't tell me what the problem was; perhaps... -
Re: Samsung monitor 2493 HM steady blue light dead
I read this entire thread today because my Samsung 2493HM is experiencing the same symptoms (black display, solidly lit blue LED). I got the impression that ivtec didn't understand budm's advice regarding how to test power supply board voltages when the power supply board isn't connected to the main board. Specifically: temporarily connect a resistor between the PS-ON and STBY (standby) pins of the smaller of the two connectors normally cabled to the main board, to raise the voltage on the PS-ON pin. PS-ON is an input signal that...Leave a comment:
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Re: Samsung 2493HM Monitor
A few days ago, my 2493HM started behaving just like asdflea's monitor: blue power LED is lit solid (not blinking) and black display. I plan to start a thread about it after I read more of the troubleshooting threads already available. In the meantime, here's a link to Samsung's service manual, which has troubleshooting info, wiring diagrams, schematics, etc:
[url]http://elektrotanya.com/samsung_2493hm_ch.ls24kie.rar/download.html[/url]
(It's in English.)
Is it possible for the moderator to change the vague Subject of this thread...Leave a comment:
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Re: ECS mcp61pm-hm 6-bad 1800uf 63 Tk caps
I've attached two close-up photos that show the capacitor that has the small brown (electrolyte) spot and very slight upward bulge at its vent. The bulge is hard to see clearly because it's so slight... the photo shot from the side is the better view. The photo shot from above is the better view of the brown spot. I believe the zillion tiny white particles are dust motes, not leaked electrolyte.
The photos were shot about 6 months ago. To my eye, the capacitor still looks the same now... the bulge & spot haven't gotten...Leave a comment:
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Re: ECS mcp61pm-hm 6-bad 1800uf 63 Tk caps
@c_hegge: I appreciate the advice. I'd appreciate more detail about the risks and tradeoffs if possible, because there's also a risk of destroying the motherboard if/when I try to unsolder the failing capacitor.
In case it helps to evaluate the risks, the capacitor that's failing is the one circled in red in the attached photo of the motherboard....Leave a comment:
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Re: ECS mcp61pm-hm 6-bad 1800uf 63 Tk caps
@Lucidbarrier: Thanks for commenting.
Perhaps I should have tried setting my soldering station to a temperature higher than 450C. But I was reluctant to risk destroying some component with too much heat.
I only replaced 3 of the old capacitors--the ones that had obviously leaked electrolyte or bulged upward--because replacing them was so difficult and because the computer worked properly after replacing those 3.
I didn't reinstall the motherboard or peripherals back into the system case, because...Leave a comment:
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Re: ECS mcp61pm-hm 6-bad 1800uf 63 Tk caps
Since the technique of heating the old solder while pushing in the new capacitor is likely to be generally useful--an alternative to removing the old solder--I wrote about it in a more general thread titled "How to remove leftover solder":
[url]https://www.badcaps.net/forum/showthread.php?t=22083&highlight=clean+solder+holes[/url]
That thread is in the "Equipment Usage, Soldering, Techniques and Reviews" subsection of the "Electronics Theory and Troubleshooting" section. (It's...Leave a comment:
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Re: How to remove leftover solder
Is it really necessary to clear the old solder from the holes? There are 3 posts in another forum thread that discuss an alternative when the old solder is hard to remove:
[url]https://www.badcaps.net/forum/showthread.php?t=8053&page=3[/url]
The 3 posts are dated 8/20/2013 through 8/23/2013. The 8/20 was posted by c_hegge, and the other two by me. C_hegge wrote that he's successfully used the technique of heating both holes simultaneously (from the bottom side of the motherboard) to soften the old solder while pushing...Leave a comment:
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Re: ECS mcp61pm-hm 6-bad 1800uf 63 Tk caps
The technique of pushing the capacitor in while heating the solder-clogged hole from the bottom side (as described above) worked, but I discovered it helps a lot to first trim the length of the capacitor lead so the lead won't bend during the pushing. (When I first tried doing it while the lead was long, it went only partway into the hole before a bend appeared, and got stuck there. I had to heat the hole again while pulling the cap to get it out... after which I trimmed the lead and succeeded.)
I suppose one would need to...Leave a comment:
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Re: ECS mcp61pm-hm 6-bad 1800uf 63 Tk caps
c_hegge wrote: "If the solder refuses to come out, then I don't clean it. I just put a bit of fresh solder over the holes, and hold the soldering iron over both holes to keep the solder melted as I push the new cap in."
Thanks. In my case, only one of the two holes is clogged, so it's unnecessary to heat both holes at the same time... one of the two leads of the new capacitor can slide freely into the unclogged hole while the new capacitor is pushed and the blocked hole is heated. I think I've already tried this,...Leave a comment:
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Re: ECS mcp61pm-hm 6-bad 1800uf 63 Tk caps
Hi, I've noticed that several posters here had trouble removing the old solder from the motherboard holes. Me too! The old solder doesn't seem to want to melt.
I've been trying to recap my motherboard (using the caps kit I purchased a few weeks ago from Badcaps). The project is turning out to be much harder than when I practiced on a trashy old board. Every step--removal of old cap, clearing hole of old solder, and getting new solder joint to adhere to hole's solder pad--has been much tougher than expected.
...Leave a comment:
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