Bush VHF81 hum

[Dorian27]

Thank you snowman for your reply .and thank you all for your help

[Dorian27]

The red coupling capacitor which one is that and what value resistor should be used after replacement of capacitor please what voltage capacitor should the 47uf be as well please

[davebms]

hello all, I think the red capacitor is c46 ,I got a pack of 5 (that's how they cam from rs) if you want one pm your address I will put one in the post
(I have 4 left) after I did my vhf81 they go in the opposite way to the other electrolytic caps

dave

[snowman_al]

Originally Posted by Dorian27

The red coupling capacitor which one is that ...

I believe Glowing Bits is referring to C46 on the top of your chassis. It is part of the FM 'detection' circuit. If FM is ok, leave it for now. It's easy to replace later.

Originally Posted by Dorian27

... and what value resistor should be used after replacement of capacitor please

?? Use the original.

Originally Posted by Dorian27

... what voltage capacitor should the 47uf be as well please

As said before, use at least a 400 volt replacements here.
The original may have a lower voltage on the can, but was from a time when the manufacturer knew it might see a surge of 340 to 360 volts shortly after switch on and was built to withstand that. (AC mains at 240 volts will get you 340+ volts DC off load. Remember for capacitor smoothing; DC volts = AC volts x 1.4)
Modern replacement electrolytic caps need to be rated to withstand any switch on surge, hence the 400 volts. Always best to over specify on the voltage (and temperature) rating.

Alan

[Glowing Bits!]

Frank, I hear what you are saying, the replacement only applies to certain red electrolytics only.
I was starting to fall asleep at the time of posting.
Rick.