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Capacitors????
brainstorm:
Hi Andy
I have recieved just one email from you and nothing in trash
Brian
Turnip:
Hi Brian,
Guess you're right - substituting a well known name for another is hell for the over 70s.
I used to love Imps, Waggon wheels and that chewy woody stuff before realising years later my jolly memories were a bit suspect.
Still feel that big caps are good (sounds a bit Animal Farm) - Chris
jimca007:
Back in the middle ages when I was a boy and most things were either valve or solid state cap values were " near as damit does " as long as the working voltage was equal to or + up to 15 % of the original.
Laterly with the ever increasing use of high frequency applications such as in SMPS's the boffins at Manufacturers courses all seem to sing from the same hymn sheet... exact same replacement, voltage temp tolerance and capacitance.
I questioned the wisdom of this at a sony course and was told with the increasing use of feedback loops, opto sensors and error detection circuits the slightly increased charge/ discharge time of a higher voltage same capacitance replacement can cause instability in a PSU.
I can't vouch for the validity of this explanation but it is a possibility....that said I've often substituted higher voltage caps and never noticed it causing a problem...
I suppose the final nail in the coffin is the fact that all manufacturers insist you do not alter or modify any part of the circuit or component specification without express authorisation of teh designers in order to maintain operational and safety parameters so from that point of view I guess its like for like.....
Ohm Supplies:
The main reason/ excuse for not changing the value of a capacitor would be explained by the phrase “by changing the value of any component you change the characteristic of the circuit “
Although this is true as is “do not alter or modify any part of the circuit or component specification without express authorisation” you could argue that capacitors should not spew forth after 12 months.It would also call into question the practise of using equivalent or uprated parts. I can think of one psu supplied by a major supermarket that had a knock of smoothing capacitor in that a different value than that shown on its canister.
When subbing caps its wise to try to stick to the original values and types, uprating the voltage is a good idea as is using slightly better quality caps. I’m sure if manufacturers had tested all the sets for 12 months before launch most of the problems would be cleared up, its also worth pointing out the number of “stock faults” on a particular set compared to the amount of components fitted in the set.
Regards
Andy
Turnip:
Hi folks,
Guess it's all health, safety and clip-boards - even when we as a country are going down the pan -
Bit too old to hold with that - puff - Chris.
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