Re: help with generic Core 2 Duo laptop with power on issues
Great, will do — don't have the bench supply in front of me right now, but will get it and test that way. I'll update the thread as I make progress.
BTW, I assume replacing this IC would involve the standard fare of steps — flux and heat gun with nearby components protected by Kapton tape, clean up pads with solder braid after chip removal, re-tin with flux and some solder in case the new IC isn't pre-balled, place new chip and apply heat gun? From the datasheet I can see it has an inner...
MacGyver's paperclip
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Last Activity: 07-13-2023, 08:44 PM
Joined: 07-01-2023
Location: Boston
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Re: what to check before replacing hybrid MOSFET/controller IC on SAMSUNG TV power bo
Incidentally, I didn't know whether to post this here or in the sister "Troubleshooting Power Supplies and Power Supply Design" subforum, but most of the recent threads in the other seem to be PC power supply related and thought it better fit here. I also didn't want to cross-post, but if that's a more appropriate place, I can re-post there or ask a moderator to move it for me. Apologies in advance if I made the wrong choice.
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Re: what to check before replacing hybrid MOSFET/controller IC on SAMSUNG TV power bo
I have this trusty old 32-in SAMSUNG LCD TV that I'm repairing a second time, and would appreciate some feedback before I pull the trigger on this second round since this time it involves an active component replacement instead of just a cap.
It's a 10+ year old TV, but it has served me well as my office/den TV and is more than sufficient in that role. I've had a few problems with it and it lacks some modern functions, but nothing too troublesome for its age nor anything I can't...Leave a comment:
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what to check before replacing hybrid MOSFET/controller IC on SAMSUNG TV power board
TLDNR; Have an old SAMSUNG TV with blown hybrid MOSFET/controller IC on power board to be replaced; replaced blown main capacitor on same power board several years ago successfully, and TV has been working fine since until this IC popped all of a sudden. Want to know what if anything to check on board to make sure before replacing and testing with new IC. Have 2 new matching ICs, DIP socket to make removal/replacement easier, a whole other known-good power board with which to compare, if necessary. -
Re: help with generic Core 2 Duo laptop with power on issues
Yeah, I had the same feeling, just from watching similar repairs but not from experience, so I appreciate the input.
I don't have one of those special-purpose power injection tools, but I presume using a bench power supply set to 1 V and current initially capped very low and slightly increasing should achieve the same result, with the bench power negative to board ground and bench power positive to the non-grounded ends of the caps in question? That's how I've seen it done in some of the...Leave a comment:
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Re: help with generic Core 2 Duo laptop with power on issues
Incidentally; as a moderator (privately) commented, the SMSC chip is of course a Super I/O chip. I referred to it as the "SMBus IC" mainly because it — among other things like keyboard control, legacy connections, etc. — does some managing of power and charging using the SMBus (protocol). The moderator also noted it looks damaged to them as well....Leave a comment:
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Re: help with generic Core 2 Duo laptop with power on issues
Thanks for responding. Of course; there is one (relatively) bigger SMD capacitor at around 1 x 2 mm square near the SMSC chip and a bunch of smaller ones. With no power or AC adapter/battery connected, large and small, all close ones measure roughly 30 Ohms on the non-grounded ends. Other SMD capacitors close by but grouped with other circuitry (like a PC Card slot controller) from their traces all show rising resistance starting from hundreds/thousands of Ohms when measured until my meter goes off-scale,...Leave a comment:
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Re: help with generic Core 2 Duo laptop with power on issues
Now, before I go in and provide a whole pile of photos, component IDs, voltages, measurements — I have very carefully inspected the board over and over for any visibly burnt or damaged component, but I cannot find any. I tested all large and most of the smaller capacitors for shorts with a multimeter, but all seem fine. There are some capacitors who trigger the multimeter to beep in diode/continuity mode, some as expected like those around the CPU, but measuring in resistance mode indicates these are not actual shorts,...Leave a comment:
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Re: help with generic Core 2 Duo laptop with power on issues
Device I'm dealing with is an old Core 2 Duo laptop, allegedly in working condition and was given to me for use in testing, random tinkering, etc. Will not turn on *completely* (explained below). I'm an experienced engineer and geek who has built and fixed hundreds of computers, only not many of them at the component level, with decent soldering skills and proper equipment for micro-soldering jobs. I'm basically using troubleshooting this as a good opportunity to teach myself more about working on board/component level...Leave a comment:
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help with generic Core 2 Duo laptop with power on issues
Hi everyone. Hope everyone's doing OK and thanks for reading.
TL,DNR; Laptop would charge, but not power on. Replaced dead CMOS/BIOS battery and identified flimsy power button daughtercard connector; got it to POST fine outside chassis. After reassembling, still would not power on. Disassembled and after more troubleshooting, now in a state where it *will* power on, but won't POST or charge. Passive and active components all visually OK, capacitors check out unshorted, voltage rails seem proper. Suspect SMBus IC damage, but need a second set of eyes to look and comment before I... -
Re: New Members - please post your introductions here
Well, hello everyone! Been a long time lurker of this awesome forum & site, but it's past time I became a poster, too, so I finally took the plunge and registered. Not to mention, I have questions to ask now that I have been spending more time tinkering with electronics lately. Briefly, I'm an experienced engineer and hacker (as in the proper & original meaning of the word) with hundreds or so computers built and fixed over the past, oh, 20 - 30 years or so, but I haven't been working much on the component/board level...Leave a comment:
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