Correct, it drives the relay via a ERR_FLAG circuit which overrides the PWR_ON control thyristor.
The question is, why is FLT pin raised?
see this manual which is as close as I can get [url]https://elektrotanya.com/samsung_bn44-00632a_l46f2p_pslf201f0_bn44-00633a_l55f2p.pdf/download.html[/url]https://Correct, it drives the relay...2p_pslf201f0_b...
nath1977
Member
Last Activity: 01-06-2025, 10:44 AM
Joined: 10-01-2023
Location: Hampshire
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Thanks for the replies folks. Further investigation has led me to both of the backlight driver IC's raising the FLT indication pin - this in turn is causing the relay to be opened. I can't see any issues with the Current sense and Over Voltage readings (based on little facts other than [URL="https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=http://patentimages.storage.googleapis.com/pdfs/US20140159217.pdf&ved=2ahUKEwiJwdr-ndmKAxX9QkEAHUmDFO8QFnoECBsQAQ&usg=AOvVaw26fNa3eIa0peiohXqB4k7c%C2%A0"]this doc[/URL]).
Will keep digging......Leave a comment:
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Thanks - that seems like a different issue and this one pulses without anything connected.
I’ve replaced all the electrolytics and or tested them out of circuit with an ESR meter and they’re OK.
Where do I go next - what the likely culprit for the PSU failing to start and stabilise?Leave a comment:
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Does anyone have a diagram for a BN44-00632 - I have one for the similar 0622b but its not identical.
So after a little more poking around with all connectors disconnected I can see a steady 390vdc across the large electrolytic which seem healthy.
A5V is steady at 5.3vdc.
B5V is pulsing in time with the relay
13V is pulsing in time with the relay
Ive had a good look around for dry joints and reflowed some which look suspicious but no better.
Any pointers would be greatly appreciated. Thank you!Leave a comment:
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Samsung F7000 occasionally cycles and fails to switch on
I have a UE40F7000 Samsung which occasionally fails to properly come out of standby. The relay clicks and the backlight flashes but then goes off again with a click, and repeats. I think its temperature related as leaving it overnight seems to allow it to switch on OK.
I assume its PSU related and had a look - it's a BN44-00632B. No signs of swollen caps or hot components.
I saw a great YouTube video on a possible PFC related issues and an underrated resistor [url]https://youtu.be/DREofE4WIvg?feature=shared[/url] though a quick trace from the SPC7011F pin 7 lead me... -
Re: Wier WA505 SMPSU output failed
PDF copy......Leave a comment:
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Re: Wier WA505 SMPSU output failed
Re-tested and ensured I was on AC and tried a second DMM too. Nothing between BB1 and BB2. Resistance is 0.3 Ohms though it looks like some big fat metal plates, which if they had failed would have been pretty obvious.
BB2 to BB7 and BB2 to BB5 both read 3.5vdc....Last edited by nath1977; 10-24-2023, 01:11 PM.Leave a comment:
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Re: Wier WA505 SMPSU output failed
Thanks - I am aware I need AC setting though may have had a brain fade at the time. Will try later and use another meter too.
Here is a partly completed diagram [url]https://www.digikey.co.uk/schemeit/project/new-project-2023-10-24-0918-22e80276702d4050b85ca94532b4a1f0[/url]
The heavy duty busbars soldered on the component side are labelled and Ive added them to the diagram.
BB2 to BB7, 3.5vdc
BB2 to BB1, 0vac
BB2 to BB5 - need to check!
R205 looks like it might be the sense feedback....Last edited by nath1977; 10-24-2023, 05:57 AM.Leave a comment:
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Re: Wier WA505 SMPSU output failed
My search continues…
I've sketched out the main components of the main output low voltage side and struggling to get a voltage reading across the transformer output prior to the rectifiers. Post rectifier diodes I get 3.5v, prior I get nothing. Will tidy my sketch and upload here. Any ideas?Leave a comment:
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Re: Wier WA505 SMPSU output failed
Hmmm joining the sense pins to the main output has made no difference to the voltage. ��Leave a comment:
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Re: Wier WA505 SMPSU output failed
I think ive worked it out but not yet been able to try. There are remote sense outputs which I didn't connect when testing. Id imagine thats the problem!...
This document prompted the thought. [url]https://cdn.badcaps-static.com/pdfs/66b163b3dcff771e88532106ef55eb63.pdf[/url]
It seems like a plausible reason for the low voltage on the 5v, and based on some other reading, the auxiliary voltage outputs on PSU's tend to rely on the primary working properly and under some load.
Every day is a school day....Leave a comment:
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Re: Wier WA505 SMPSU output failed
9 in total, Rubycon ZLK and some Samwah WL
I guess these are not top spec - Im not looking to run this thing extensively or put it in to live operation. Its a hobby repair to some old broadcasting kit I want to see running once in a while.
Using a DMM I can get 2000uF measured on those parallel input caps. I realise this isn't a rigorous test so should look at replacing them next....Leave a comment:
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Re: Wier WA505 SMPSU output failed
Rubycon 35v and 10v electrolytics on the outputs....Leave a comment:
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Re: Wier WA505 SMPSU output failed
Pics enclosed. Thank you....Leave a comment:
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Re: Wier WA505 SMPSU output failed
Still looking for some help if I can. Load resistor, and several output smoothing capacitors replaced.
I can now get all of the low current voltages present 24v, -5, 15v etc. However once loaded with say the cooling fans on the 24v, there isn't enough power to drive the fans. Also, the high current 5v is only reaching 3v.
No obvious faulty components elsewhere on the board. Any obvious things I need to go after first?
Thank you!Leave a comment:
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Re: Wier WA505 SMPSU output failed
What a top tip! After a little scraping and grinding I managed to get some readings. 100R it is! Thank you so much 😊...Leave a comment:
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Re: Wier WA505 SMPSU output failed
Having removed the resistor and measured it again, it’s 18k. Seems very high to have ever been that hot. I’m assuming this is a false reading as a result of it overheating.Leave a comment:
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Re: Wier WA505 SMPSU output failed
Thanks. Can I ask what would be the likely cause of this fault. I realise caps dry out with age and fail - so why did the resistor frazzle too? Will the output voltage have risen when the cap failed?Leave a comment:
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Re: Wier WA505 SMPSU output failed
Thanks - I failed to mention the resistor is also across the 5vdc output.Leave a comment:
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Wier WA505 SMPSU output failed
Hi,
Im about to repair a failed Wier WA505 power supply which hasn't been used for many years. It was working for 30 mins or so, then started to smell bad so switched it off quick.
On closer inspection a 1500uF cap across the 5v output has swollen. Adjacent to this is an overheated (open circuit) resistor.
Ive removed the electrolytic cap and resistor - the cap replacement is straightforward and will replace the adjacent ones at the same time. The resistor looks like it sits across the output. Any ideas what value this is likely to be? Was thinking 100R 1/2watt would be suitable....Last edited by nath1977; 10-01-2023, 06:08 AM.
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