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Re: Acer Aspire 8530-754G64Mn Model MS2249 - black screen, not booting
As you won't guess it anyway, here's the solution:
According to Acer's service guide I would have had to totally disassemble the whole thing in order to get to the lithium RTC battery (CMOS battery). So this button cell really was the last thing I'd like to check. But I found a shortcut.
I only had to remove 6 bottom screws to be able to pry open the left front corner of the case. I used a peace of wood to hold it open while replacing the button cell. The old cell had been discharged...
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Re: Acer Aspire 8530G no power up
...quite a while ago but has your Aspire 8530G eventually been salvaged?
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Acer Aspire 8530-754G64Mn Model MS2249 - black screen, not booting
Hello,
I've got my grandson's dead Acer Aspire 8530G-754G64Mn Laptop Model MS2249 on my 'dissecting table'. Pressing the power button gives back a few signs of life to it. The fan is spinning silently, the multimedia player's lights and volume-control touch slider appear to work but I can't hear a sound. An audio CD will spin for a little while but won't play. Screen and external monitor remain black. I removed battery, RAM and HDD, haven't found the RTC button cell yet. Both heat-piped processors, CPU and GPU card get about hand warm.
The only really working thing is the...Last edited by badhat; 03-15-2016, 06:36 PM.
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Re: Orion TV26266 won't start when cold (ChiMei Mainboard PCBF40 CMH140A)
Which ones to begin with?
[CENTER]
(this is for educational purposes only and not meant to encourage anybody to build similar designs )[/CENTER]
I currently don't have an ESR meter. I just ordered one of the [URL="http://www.ebay.com/sch/i.html?_from=R40|R40&_nkw=LCD+Transistor+Tester++Capacitance+ESR+Meter&_in_kw=1&_ex_kw=&_sacat=0&_udlo=&_udhi=&_ftrt=901&_ftrv=1&_sabdlo=&_sabdhi=&_samilow=&_samihi=&_fsradio2=%26LH_PrefLoc%3D1&_sargn=-1%26saslc%3D2&_salic=1&_sanli=1&LH_SubLocation=1&_sop=15&_dmd=1&_ipg=50"]cheap...Last edited by badhat; 09-02-2014, 05:15 AM.
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Re: LCD Monitor With Flickering Dimm Backlight and Hissing Noise
Now that I'm back to this forum with another case I stumbled across my old thread of January this year and I'd like to give some feedback.
What happened since? I wasn't able to sell the good parts on eBay but I found and bought a working power board for 20 EUR :-)
My Acer H243H monitor is since doing well with it.
Best regards,
Badhat
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Re: Orion TV26266 won't start when cold (ChiMei Mainboard PCBF40 CMH140A)
yes, sure:
These are photos of identical boards, more or less.
Regarding the hot caps I suppose the linear voltage regulators are right underneath and thus heating up the caps. I'll have a closer look tomorrow....Last edited by badhat; 09-01-2014, 06:03 PM.
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Orion TV26266 won't start when cold (ChiMei Mainboard PCBF40 CMH140A)
Hello,
I've got an Orion TV that takes 10 to 15 minutes to start at temperatures below 18 degrees Celsius. I think it might be a bad caps issue. I was planning to heat up the usual suspects a bit with the tip of my soldering iron, all one by one until I find the lazy one.
But now in the summer time temperatures simply won't get low enough to repeat the effect. I carefully applied some ice spray to most of the caps and scaler chip but with no effect.
Any more ideas?
Best regards,
Badhat
ps
one observation: a couple of tantalum...Last edited by badhat; 09-01-2014, 01:50 PM.
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Re: LCD Monitor With Flickering Dimm Backlight and Hissing Noise
I gave up, I'm selling the good parts on Ebay.
You're right, Budm, the inverter frequency is too low, otherwise I wouldn't hear it at all. Must be something around 10 kHz or even lower. I could see a continous 'spiky' waveform on a friend's oscilloscope for a few seconds, then a few seconds pause, then the waveform again with the pulsewidth modulation kicking in. Hard to trigger since the PWM frequency isn't stable. That's what makes the chirping sound. Everything appears ok except the frequency and the...Last edited by badhat; 01-23-2014, 07:38 AM.
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Re: LCD Monitor With Flickering Dimm Backlight and Hissing Noise
My transformers are ok, no arcing, corona discharge or the like. The chirping / hissing noise comes directly out of the PCB. I first thought of HV creepage and sprayed some clear acrylic laquer on and under the HV area of the board. May be it's imagination but I think it helped a bit. On power-up the inverter starts with a relatively clear and stable sinus tone of a few kilohertz. After about 2 seconds it stops and after about 2 more seconds it starts again with that chirping hiss.
I disconnected all high...Last edited by badhat; 01-16-2014, 05:39 PM.
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Re: LCD Monitor With Flickering Dimm Backlight and Hissing Noise
In the new image (see above) you can see the rosin crumbs. I added tin-lead solder and rosin flux to extract the transformers. Although benzine is not a good solvent for rosin I'm afraid the it could have dissolved and deposited part of the rosin at the high voltage windings. Should I use alcohol to dissolve the rosin residues and then benzine again to get rid of the alcohol? Maybe I'd first dry the transformers with a hair dryer, connect them and see what happens.
I mentioned above I could get a pair...
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Re: LCD Monitor With Flickering Dimm Backlight and Hissing Noise
here's some photographs
After drying the washed transformers I'll insert them inversed, I mean upside down so I might see some arcing....Last edited by badhat; 01-11-2014, 07:33 AM.
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Re: LCD Monitor With Flickering Dimm Backlight and Hissing Noise
Yes, that's my board. Thanks for (the link to) this great image. My board is stamped Rev. D but I haven't found no difference yet.
I measured some 650 ohms at the HV windings of the transformers. I'll unsolder and pull them and clean everything right now. I've seen bottom views of this kind of transformers during my searches showing the open windings. I always thought high voltage transformers should be sealed somehow :-)
Pictures will follow, I promise.
...
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