M
Mickymoody
As long as the 2200 micro farad is good, overrating them is even better. Why the manufacturers use the bare minimum is strange? Obviously costs.
Nice one.
Nice one.
Samsung LE40M87BD 40" LCD TV Clicks but won't turn on
- Thread starter IJWS15
- Start date
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Actually, that's slightly worrying. In my experience, better (more reliable) capacitors will always be larger - especially if they have a higher voltage rating or capacitance. Your Maplin capacitors may not last long.
See http://www.satcure.co.uk/accs/television_capacitors.htm
M
Mickymoody
Actually, that's slightly worrying. In my experience, better (more reliable) capacitors will always be larger - especially if they have a higher voltage rating or capacitance. Your Maplin capacitors may not last long.
See http://www.satcure.co.uk/accs/television_capacitors.htm[/QUOTE]
Not necessarily, the manufacturers go for what is cheap, if the new caps have a better voltage rating, and a better temp rating, and therefore a better ESR, they would be OK. Larger caps might be used because they are older technology, and cheaper. As the new caps are higer rated, they will run cooler anyways, thus be more effective. So for me, size does not necessarily matter, as long as the specs are good. So says the ladiez.
Fair comment. So what is the ESR of the Maplin capacitor?
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M
Mickymoody
Without the technical specs, or physically testing the caps, it's impossible to guess, versus the OE spec that was fitted. I doubt that the ESR is listed, as it would vary from each manufacture?
Maplin should know. If a seller can't provide the ESR value then it's likely that it's high, meaning that it's a "general purpose" electrolytic, which may not last long in a switch mode PSU. Typically, the value will be 0.03 Ohms or lower at 100kHz.
M
Mickymoody
I thought high ESR is good? But was wrong, good call.
The problem with using incorrect capacitors is that the PSU may appear to function perfectly at first but you may notice a little interference on the picture, which gradually becomes worse. This occurs because a capacitor with too high an ESR allows short-duration high-voltage spikes to escape on the "DC" supply lines, causing the interference. The picture can be affected in different ways, including a slight "graininess". The interference can also be superimposed on the tuning voltage, causing problems with tuning and some quite weird effects.
The capacitors will run warm, or even quite hot to the touch, and the problems will become worse.
There's a good article about ESR here:
http://members.ozemail.com.au/~bobpar/esrtext.htm
ESR is quite simple, by the way. It's just the impedance of the capacitor, which is usually measured at 100kHz for convenience. "Effective Series Resistance" is just a fancy term used to describe it.
The capacitors will run warm, or even quite hot to the touch, and the problems will become worse.
There's a good article about ESR here:
http://members.ozemail.com.au/~bobpar/esrtext.htm
ESR is quite simple, by the way. It's just the impedance of the capacitor, which is usually measured at 100kHz for convenience. "Effective Series Resistance" is just a fancy term used to describe it.
Marlin are pretty useless for specialised components such as these.
They only do one range of high temperature capacitors which is the first thing to filter on when choosing replacements. They don't list a manufacturer or spec.
If you didn't fit the high temperature caps then I would strip them out again and fit proper rated ones. If you did then they will probably be ok
They only do one range of high temperature capacitors which is the first thing to filter on when choosing replacements. They don't list a manufacturer or spec.
If you didn't fit the high temperature caps then I would strip them out again and fit proper rated ones. If you did then they will probably be ok
Temperature rating doesn't matter per se but, certainly, any capacitor rated at less than 105°C will NOT have a low ESR value.
Conversely, a 105°C rating does not by itself guarantee that you have a low ESR capacitor! The only way to be certain is to measure it or to see the written specification.
Conversely, a 105°C rating does not by itself guarantee that you have a low ESR capacitor! The only way to be certain is to measure it or to see the written specification.
M
Mickymoody
Because new components have been introduced, the whole set needs recalibrating.
I think you mistake ESR for misunderstanding what it means? Electrical components are tested 'for convenience', for fun, I suppose?
I don't think he was disagreeing.
(Actually, I don't understand what he means, at all. Which set of what needs recalibrating?)
(Actually, I don't understand what he means, at all. Which set of what needs recalibrating?)
Replacing the capacitors in a PSU brings it back to the original specification (or better - i.e. less ripple on the DC supplies). Nothing on the PSU should need to be adjusted. It is self-regulating - usually using a comparator and an accurate voltage reference source. There are no components in a PSU, apart from electrolytics, that have a limited life, provided that they were correctly specified in the design.
We are well past the age of thermionic valves! (Although I'm old enough to be familiar with them!)
See A Beginner's Guide
We are well past the age of thermionic valves! (Although I'm old enough to be familiar with them!)
See A Beginner's Guide
Just dug this out as son's TV, slightly later model, seems to be developing the same fault.
Daughter's TV still going strong on the cheap Maplin capacitors.
Daughter's TV still going strong on the cheap Maplin capacitors.
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