Ady2017
Member
Last Activity: 07-24-2022, 04:36 AM
Joined: 12-21-2017
Location: Nottingham
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Any good references for variable capacitor design?
I have recently decided to put together a 1930's style crystal radio as a father-son project to get him started in electronics. The lack of availability of now-obsolete variable capacitors is causing a big headache. From what I have seen on the internet, a number of people have resorted to making their own variable capacitors but have not given any details about how they designed them. Does anybody have any old references for the design of variable capacitors which includes details such as plate spacing, plate size, number of plates, best materials to use, etc. -
Re: LG 42LD490 stuck in standby with flashing red light
Just thinking about it a bit more, it makes sense that it would be a main board issue as once the TV is on, it would happily keep working 24/7 until I switch it off and let it cool down. My bedroom TV on the other hand likes a new set of PSU caps every other year and the first sign of trouble is it keep switching itself off when it gets hot.
I have had a ESR meter on my list of things to buy for a while but I am a bit dubious about buying anything from ebay and especially being dispatched from China!Last edited by Ady2017; 11-16-2021, 03:10 PM. -
Re: LG 42LD490 stuck in standby with flashing red light
Yes, that seems like a great idea as whatever component it is that is faulty it does not like being cold. Try warming up the PSU first and if not then try warming up the suspect IC on the main board. It is one of those challenging intermittent problems - the TV is on right now and is working perfect but nobody dare turn it off!Leave a comment:
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Re: LG 42LD490 stuck in standby with flashing red light
Update - I have just been around the back of the TV and tried to listed where the high pitch sound is coming from which it makes while trying to start up. It is definitely coming from the main board and not the PSU board and so I guess that is the most likely culprit then.
It looks like the place selling a capacitor kit for the PSU to fix the problem is misleading.Leave a comment:
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LG 42LD490 stuck in standby with flashing red light
The problem with my TV is very similar to an earlier post but there was no final solution posted.
When the TV is first turned on from cold it will not turn on. The red standby light begins pulsing and a high pitch whine is heard. The back light remains off. If the TV is left trying to boot like this and then turned off and on again a few times then eventually it will turn on and sit there working all day long.
I initially suspected the PSU after spotting this kit for sale,
[url]http://www.ohmsupplies.co.uk/epages/62027733.sf/en_GB/?ObjectPath=/Shops/62027733/Products/KIT229[/url]... -
Is there a manufacturers tolerance for ripple?
Hi all
I need to replace a 680uF 35V SamYoung NXB cap which has got a ripple of 1820. Whilst passing my local little electronics shop I picked up what they had in stock which was a 680uF 35V Panasonic FC with a ripple of 1655.
As the ripple rating is only 9% below what the original was I am wondering whether to risk it and fit it.
The catalogues specify a capacitance tolerance of +/-20% but state nothing about the ripple. If there is a similar tolerance for ripple then I might be worrying about nothing. Does anybody know?
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Is it ok to use a capacitor with a much higher ripple?
Hi all
I am trying to source some new caps for the power board on my LG TV. The one I am currently struggling to find a replacement for has the specs:
Sam Young KMG 680uf 50V with a rated ripple current of 973. According to the catalogue these seem to be a general purpose capacitor and it is not clear why LG have used them on the power board.
I like to use Panasonic capacitors but most of these have got a ripple voltage of 2-3 times the figure of the original capacitor. My preferred FR capacitors are 3160 while the FC ones are 2215. Would going from 973 to... -
Re: Capacitor advice
TV is a LG 42LD490
Power board is, EAX61124201/16 REV 1.3
It is a 10 year old TV that has sometimes been on 24 hours a days and is still on its original caps so has done well and deserves a bit of TLCLeave a comment:
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Capacitor advice
Hi all
The time has come to replace the caps on the power supply board of my LG TV. It works fine when it is on but it is a pain to switch on which is a common fault apparently. All the caps currently in there are the original ones from the factory.
The main filter cap is a Sam Young KMF which is for SMPS applications but the second in the circuit is a Sam Young KMG which seems to be a general purpose capacitor. All the rest of the capacitors on the board are Sam Young NXB capacitors which are for SMPS applications. It does not make sense why all the caps on the board... -
Re: Can you revive TV remote controls?
Thanks I will have a look for the rubber pad kits. I don't know what my dad was talking about then but it was 10+ years ago!Leave a comment:
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Can you revive TV remote controls?
Hi all
Quick question - can you get TV remote controls working again when 1 or 2 buttons stop working?
When I was growing up I seem to remember my dad telling me that there was sometime like a grease that you could put on the underside of the rubber key to help them make the circuit when they touch the PCB.
Thanks -
Re: Difficulty trying to match ESR of a replacement capacitor
Yes, it is on the main input.
I finally found one or two with a low dissipation factor but they have got a short life of about 2000 hours. Others with a slightly higher ESR are often 10,000 hours. I was expecting to find something specifically designed for power supply applications but no luck yet. I have found ones for 'ballast' applications, whatever that is?
Does anyone have any experience with the Panasonic EE series? Specifically this one,
EEUEE2G101Leave a comment:
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Difficulty trying to match ESR of a replacement capacitor
Hi all
I am trying to find a replacement capacitor for a CapXon KM 100uF 400V. I have read that the big ones really go wrong but it is the last one left on the power supply board that has not been changed and the TV is still playing up so it is getting swapped too.
I have read that I need to find a replacement cap with the same or higher ripple and the same or lower ESR, with all the usual being matched. The ripple is easy to match but the ESR seems to be a challenge.
From the KM datasheet I have got, dissipation factor = 15% (therefore 0.15).
I have...Last edited by Ady2017; 10-13-2020, 04:57 AM. -
Re: Capxon capacitor codes?
Attached is a picture of a power supply board the same as mine. How can you tell which factory it came from?...Leave a comment:
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Re: Capxon capacitor codes?
Yes, it makes sense that it could be the date code as it is a 2011 TV.
There is only 2 Capxon capacitors left on the power supply board now, all the rest have failed one after the other and have been replaced with Panasonic FR ones. In future projects I will just replace the lot in one go.
The TV is a Logik L24DVDB11 if anyone has a service manual?Leave a comment:
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Capxon capacitor codes?
Hi all
I have got a suspect capacitor in my TV Power Supply. The old one is glued to the PCB but I want to order a new one before I pull the old one. The side with the ratings is the side that is glued down!
Does anyone know what spec a Capxon KM P1106 capacitor is?
There is no mention of the codes in the capxon catalogue, only ordering codes.
Thanks -
Re: Any recent feedback for Samwha caps?
This was quite funny to see as he did a awful job of replacing all the caps with whatever he could find and bodging them in. Looked a right mess afterwards....Leave a comment:
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Re: Any recent feedback for Samwha caps?
The original capacitors were CapXon KF series 105 degrees. Yes, looking at the datasheet they are quoted as being 'Low Impedance'. I already have some 'FR' capacitors which as far as I can make out are Panasonic and look like these are low impedance too so will swap them out to be safe.
When selecting capacitors, is it sufficient to match them according to the uF, the Voltage and if they are low impedance or general purpose?Last edited by Ady2017; 03-18-2018, 05:10 PM.Leave a comment:
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Re: Any recent feedback for Samwha caps?
Hi
The original ones were CapXon, 1000uf 25v (2 off) and 1000uf 10v. Replaced with 1000uf 25v and 1000uf 16v.
I had to get these from Maplins. Can not remember what series they were but they were the 105 degrees ones.
[url]https://www.maplin.co.uk/p/1000f-16v-105c-radial-electrolytic-capacitor-dt69a[/url]
[url]https://www.maplin.co.uk/p/1000f-25v-105c-radial-electrolytic-capacitor-dt70m[/url]
ThanksRe: Any recent feedback for Samwha c...r /> Hi<br />...Leave a comment:
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Re: Any recent feedback for Samwha caps?
Ok, thanks. If they still last for a few years then they will be ok then. I have bought some better ones to keep to one side in case the Samwha ones go. Thanks for the reassurance.Leave a comment:
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