Re: Acer X223HQ (Version Bbd) on/off-power-cycling
Alright, I'll start with that.
I've also been thinking that maybe the power button itself might be "bad". I had a faulty button on my hanns.g 2 years ago, which would manifest itself by repeatedly displaying the osd menu. Replacing that switch solved the problem.
I'll report back after going over the board with a microscope....
usbdevice
Member
Last Activity: 11-18-2022, 06:49 AM
Joined: 08-29-2012
Location: Zürich
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Re: Acer X223HQ (Version Bbd) on/off-power-cycling
Hi Per, thanks for your reply. I forgot to subscribe to the thread so I didn't get notified of your reply, therefore my late response.
Thank you for clearing that up!
Bad solder joint could very well be, although I'm having trouble thinking of a reason why the power cycling would stop after using the power button if a bad solder connection would be the only fault.
Would you care to take a guess as to where I should start looking for (a) bad connection(s)?
...Leave a comment:
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Acer X223HQ (Version Bbd) on/off-power-cycling
Hi all
There's two other threads about this monitor with seemingly the same problem. The problem was resolved in one case by replacing the entire PSU board and in the second one by replacing an unknown IC.
[url]https://www.badcaps.net/forum/showthread.php?t=50657[/url]
[url]https://www.badcaps.net/forum/showthread.php?t=40512[/url]
The first one has pictures of the pcbs and I noticed that there's one IC and assorted caps not populated on mine (but the PCB itself looks identical) so I thought that'd warrant a new thread.
It's my... -
Re: Macbook Pro A1989, 820-00850-A, water damage
Finally, the last order arrived today and I can get back to work on this.
I'll let you know how it goes.Leave a comment:
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Re: Macbook Pro A1989, 820-00850-A, water damage
Would there be any way to test for this at this point?
Yeah, I kind of figured that. But since there is no pressure to have it fixed, I'm going to see how far I can take it without too much of an investment in hard to find components. There's also the learning experience.
Gotcha.
I'll report back when I have the replacement parts installed, probably will be in a few weeks seeing as the sources will be mainly aliexpress.
Thanks...Leave a comment:
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Re: Macbook Pro A1989, 820-00850-A, water damage
Sorry, this took longer than expected.
Here we go:
Visual inspection yielded no clues, I had a friend look over it too.
So voltage injection. I didn't have a hot-air station last night so instead of removing ICs or Transistors I removed associated resistors (which in all but one case were the components that were getting warm anyway) with a regular soldering station.
In the order things started warming up:
At 220mA and approx. 1.8V (of course I had to increase the voltage...Leave a comment:
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Re: Macbook Pro A1989, 820-00850-A, water damage
I was able to measure the resistances between the inductors and PP5V_G3S during lunch break. The lowest ones are just above 8 Ohm:
L7210: 8.34 Ohm
L7220: 8.35 Ohm
L7270: 14.74 Ohm
L7410: 8.06 Ohm
L7420: 8.1 Ohm
L7430: 8.1 Ohm
L7702: 26.34 Ohm
L8102: 18.61 Ohm
The rest are even higher.
I'll continue tonight with the voltage injection when I have more time.
Thanks again!Leave a comment:
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Re: Macbook Pro A1989, 820-00850-A, water damage
L7600 to GND is 6.06 Ohm. Is that considered a (partial) short?
Continued thanks.Leave a comment:
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Re: Macbook Pro A1989, 820-00850-A, water damage
Alright, moving on.
At 2.5A U7600 (CSD58879) started warming up. I've removed it from the board and the short from PPBUS_G3H to GND is now gone.
Should I check anything else before trying to source a replacement?
As always, thank you for your help.Leave a comment:
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Re: Macbook Pro A1989, 820-00850-A, water damage
Hi piernov, thanks for your reply.
I measured the resistances from the inductors to PPBUS_G3H. The ones with the lowest resistances were:
L7210: 2.5 Ohm
L7220: 2.5 Ohm
L7270: 9.6 Ohm
L7410: 2.3 Ohm
L7420: 2.3 Ohm
L7430: 2.3 Ohm
L7702: 25 Ohm
L8102: 43.5 Ohm
L8100: 346 Ohm
The others are in the tens of kOhms range and higher.
For reference: PPBUS_G3H to GND measures at 0.3 Ohm which is basically the contact resistance of the multimeter probes....Leave a comment:
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Macbook Pro A1989, 820-00850-A, water damage
Hi all
This laptop was my wife's, a little water dripped onto/into it while it was stowed in her backpack. Unfortunately she couldn't wait and tried turning it on right after she realized what had happened - "It didn't turn on but got hot."
Since I'm naturally curious and I hate to throw hardware away I figured I'd have a go at and see if I can repair it.
I've been searching for info on this particular machine but there's so much stuff I'm having a hard time putting it all together.
The power sequence for example is still unclear to me.
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Re: Hanns-G HG281D, LCD Monitor no power
Hi all
About 1 year ago (post #349) I had resolved the first trouble with my Hanns.G (screen going black for a second or 2 every once in a while) with the info in this monster-thread.
Now, 1 year later, the PSU of my monitor has started to act up making it more and more difficult to get the display to turn on.
And once again, with the info accumulated here, my monitor is running fine again. After replacing the 8 caps mentioned again and again (C603, C606, C707, C406, C605, C108, C111, C114) the monitor powers...Leave a comment:
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Hi usbdevice
I have a similar problem to you with my Hanns-g HG281DJ.
The monitor is taking longer and longer to work when first switching on, but once it has warmed up it works fine.
I can also get it to work quicker if I press ctrl/alt/delete.
When the blue windows screen comes up with start task manager etc. it usually works fine.
If I then open the task manager and keep the task manager window open the monitor will be working much sooner than if I just leave it on the desktop screen.
There are also sometimes certain web pages... -
Re: Hanns-G HG281D, LCD Monitor no power
Hello all
First I'd like to thank everyone who has contributed to this thread and shared their experiences repairing this particular monitor.
Second, sorry for the long post. This is a success story so you might not even want to read this.
I bought my Hanns.g 4 years ago and it started showing first signs of failure about one year ago. The monitor would go black for a second or two, and then the image would come back.
For a couple of months now, when booting my pc the image would be fine, but a...Leave a comment:
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