Re: Samsung LS24F354FHNXZA - partially working no standby
Sure, it works great now and I haven't had any issues with it after the board swap, well aside from a minor nitpick where it locks you out of certain settings such as brightness if you enable other settings and the stand isn't great but ignoring that it's a very nice display and even with the added cost of a new board I still paid less than half the $100 retail price, so I'm quite happy with the result....
vgamesx1
Member
Last Activity: 04-16-2022, 04:08 PM
Joined: 01-05-2021
Location: East Tennessee
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Re: Airthereal APH260 mcu appears to constantly reset
Well I've replaced some of the remaining caps and read a bit of that datasheet for ideas, but I don't think this is getting fixed...
Of course, I'll keep the purifier since the motors in these things are super simple, so I've just hardwired it to its lowest speed and later on I can wire in a 4 position switch or should I feel compelled to do so, it doesn't look like it would be too hard to desolder the mcu and hack in my own.Leave a comment:
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Re: Airthereal APH260 mcu appears to constantly reset
Just a few test points, but they aren't useful for me as I don't have an oscilloscope, so the only thing I can see is that it does have a clock, and it's around 60khz, although that said if I can find pin INT0 then I could hook up UART and see if it displays anything.
*Gasp noises* I only just noticed on [URL="https://www.socmcu.com/en/index.php?m=Product&a=detail&id=67"]this[/URL] page that the chip has Low voltage reset, so maybe if it or normal reset were repeatedly being pulled low it would...Last edited by vgamesx1; 01-16-2021, 09:21 AM.Leave a comment:
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Re: Airthereal APH260 mcu appears to constantly reset
So I replaced not all but most of the caps on the 5v line and not much has changed, it will pause and occasionally do some funny flickering of the main display, but it'll soon go back to clicking away, I'm not so sure that this going to work.
(Note the electrolytic caps I removed have been replaced on the under side of the board as it's more accessible.)...Last edited by vgamesx1; 01-15-2021, 08:37 PM.Leave a comment:
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Re: Airthereal APH260 mcu appears to constantly reset
Update, I tried your experiment by placing some metal tweezers over the springs with a croc clip to ground and it'll sometimes kinda pause for a moment as if it tries to boot then it crashes and goes back to the previous resetting, I also removed C6 and the electrolytics surrounding it, then bodged a through hole cap in its place, this hasn't changed its behavior either....Leave a comment:
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Re: Airthereal APH260 mcu appears to constantly reset
I know it isn't the best photo but there are a couple, could you be more specific? C5? C6 (it's the one next to R6)? C6 and C11 appear to be a part of the power line btw, not sure what C5 is doing (maybe feedback? I see 2.5v on it).
Wait you're not thinking EC2 is a cap are you? Lol if that's what you were referring to sorry about that, it's the regulator.
Edit: Maybe it was something I did while poking around, but now I'm seeing a short on C6 and C11 or something else there is making them appear short......Last edited by vgamesx1; 01-15-2021, 09:01 AM.Leave a comment:
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Re: Airthereal APH260 mcu appears to constantly reset
Huh, for some reason I hadn't thought about noise on the switches but that makes a lot of sense, thanks!
Wait but wouldn't the noise have to be from the caps then? Because the transformer shouldn't have any power when I powered it from my supply, right? Well anyway I don't have any good caps just a bag of cheapos and I can't replace the 400v ones either but I'll replace the ones I can and update if it works later.Leave a comment:
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Airthereal APH260 mcu appears to constantly reset
My air purifier does this weird flickering/resetting, at first you might rightfully assume it's a power supply issue, however as you can see [URL="https://www.youtube.com/watch?v=6cCGN4WLank"]in this video[/URL] I've uploaded a demonstration of the problem where I'm injecting 5v to the board directly, also double-checking while powered from mains, the 5v supply looks solid and since there aren't many components, I've checked nearly all of them for shorts but nothing appears to be wrong with the support circuitry at least as far as I can tell, so my best guess at this point is the MCU... -
Re: Samsung LS24F354FHNXZA - partially working no standby
Ohm my transistor! Yeah, C610 was 99% certainly A problem...
I couldn't fit it back on because I accidentally covered it in solder thus I bodged a thorough hold cap into its place so I could test IC600 and not only did it boot on first power on it stayed on at least until it went to sleep, and I unplugged it.
That's so weird though since I couldn't measure anything on that cap with my DMM out of curcit, further testing is of course needed, actually never mind, although it does seem to stay...Last edited by vgamesx1; 01-13-2021, 08:37 PM.Leave a comment:
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Re: Samsung LS24F354FHNXZA - partially working no standby
Yes that's the cap I mentioned in the main post, it looked like it might've had a short, so just I went ahead and replaced it regardless and I'm fairly certain it's the correct value, but in hindsight you can see it goes straight to the backlight which works perfectly fine (when it wakes up) and that was likely a complete waste.
In circuit, I just tested it by itself and it's hard to measure, but I seem to be getting OL and nearly 100nF so good call, maybe it is ok, also R615 appears to be a 0ohm...Last edited by vgamesx1; 01-11-2021, 02:11 PM.Leave a comment:
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Re: Samsung LS24F354FHNXZA - partially working no standby
That's just some flux where I didn't do a great job of cleaning the board, sorry for the confusion, I double-checked it's certainly fine.
Although one thing I did find is on the 5v line, C610 was very low resistance at roughly 20ohm and removing it did bring it up to 3.8v and my 3.3v up to 3.19v, but it didn't fix my issue and one time it booted up I did confirm the line went up to 5v, so is the regulator going bad prehaps?Last edited by vgamesx1; 01-09-2021, 04:52 PM.Leave a comment:
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Re: Samsung LS24F354FHNXZA - partially working no standby
Whoops, surprise I'm just being dumb, and I didn't think the lower power rail was very important and also it's easier to see in a blown up photo where the 3.3v and 5v test points are... Well after checking it I'm getting 2.8v and 3.4v there, so both lines but mainly the 5v is pretty low, but it isn't shorted as far as I can tell, and I'm still not sure what's wrong yet.Leave a comment:
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Samsung LS24F354FHNXZA - partially working no standby
I got this off ebay very cheap as no power, well turns out it does have power and even shows a display, but it's very random and will only work for at most about 30 seconds before it becomes fully dead/no power again, just to be certain I've unplugged the LED backlight and display cables but that has had no effect on functionality, it runs on roughly 14v, at idle draws 0.02W and will go up to 6W or more when functioning correctly.
Thus far as a matter of course I've replaced the main power rail capacitor and inductor (slightly higher value) and I double-checked the power mosfet... -
Re: New Members - please post your introductions here
Hello, I', looking to get help fixing a monitor I just got.Leave a comment:
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