Quote:
Originally Posted by DKW F102
Hi again. Thanks to everyone who has explained about the 'audio coupling capacitor'. As I said in my second posting, I have been replacing the 'audio coupling capacitor' as a matter of course ( not realy knowing what it does) while changing all of the other wax paper capasitors, or to use a new confusing term ' Toffees' (so called as they are toffee colour and sticky too). I geuss that all of the resistors and capasitors should ALWAYS be checked during the restoration of a radio / amplifier. If they are not in spec then it pays to change them. I do wonder if people who talk about 'the valve sound' are used to sets with duff resistors and capasitors making them think that all valve stuff should sound like that. Anyway, I'm of to measure some 'audio coupling capacitors' ... !!
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Quote:
Originally Posted by DKW F102
Hi. Stevehertz ... When you say to check capacitors for resistance, how can I tell what the reststance should be ? I've only seen uF/nF/pF and the voltage on them. Is this the E.S.R I suppose ? I bought an E.S.R meter when I started geting my kit together but could not realy understand what it was supposed to be for, so have not used it since. I measure my resistors with my AVO 8 and my capacitors with a Greyshaw CR 50 C/R Bridge. Both the AVO and the bridge have been overhalled /aligned by a kind member of this forum. Am I missing something I should realy be paying attention to ?
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The simple way is to connect your capacitor to your meter which should be set to read 'resistance', and set to 'high value' ohms range, the highest range it has. If you get
any resistance reading - a low value is a definite no-no - but even a high value (100's of K ohms) means that the cap will be able to pass DC and should be replaced. Ideally you want to see a reading that is very high; in excess of 10 or 20 millions ohms (Megohms), or better still, 'open circuit' ie an infinitesimal amount of resistance.