Replacing capacitors - UK Vintage Radio Repair and Restoration Discussion Forum

skamanuk · 15th Mar 2017, 2:39 pm

Hi can anybody tell me what modern value capacitors I can safely replace the following with.

1. 0.002uf 350volt
2. 0.01uf 350volt
3. 0.005uf 350volt
4. 0.005uf 150volt
5. 0.04uf 150volt

Pye black box amplifier . The above caps are all original HUNTS so need replacing. Gary

Boater Sam · 15th Mar 2017, 2:58 pm

1, 0.0022uf 2.2nf 2200pf
2, 0.01uf 10nf
3, 0.0047uf 4.7nf 4700pf
4, 0.0047uf 4.7nf 4700pf
5, 0.039uf 39nf

All voltages to be the same as originals or higher.

15th Mar 2017, 5:17 pm

A frequently asked and not unreasonable question, time for a sticky I think.

Station X · 15th Mar 2017, 5:21 pm

There is one, but no one ever reads it;-

http://www.vintage-radio.net/forum/s...ad.php?t=88767

skamanuk · 15th Mar 2017, 6:24 pm

A followup question if I may. I need to replace the mains smoothing can (picture attached) where would I track this or a modern version of?. The can only has two pins as can be seen by picture 2

Edward Huggins · 15th Mar 2017, 6:53 pm

The can is earthed. You are unlikely to get a "modern" version of what you have. You will need to buy 2 seperate electrolytic capacitors of similar (or near as) value and at least the same operating voltage. If this is in the smoothng circuit, and it looks like it, you MAY be able to use a 16uf and a 32uf. These may lower the hum level as well. We really need you to provide the make and model number of the unit so it can be can be checked with the circuit diagram.

15th Mar 2017, 7:22 pm

Quote:

There is one, but no one ever reads it;-

Lack of advertising or... A big banner saying "Beginners start here"?

TonyDuell · 15th Mar 2017, 7:52 pm

That smoothing capacitor is actually 2 capacitors in one can. A 25uF one and a 12uF one rated at 350V each (uF = microfarad). The negative side of each capacitor is connected to the can, and therefore to the metal chassis of the amplifier, the positive sides are connected to the tags. Oriignally one of the tags would have had a red mark on it (possibly on the rivet fixing it to the plastic base of the can), as the writing on the can says that would be the 25uF one, leaving the other tag for the 12uF capacitor.

If the mark is no longer present you have to trace where each tag is connected to and compare it with the circuit diagram. That will tell you which is which.

The nearest modern equivalents are 22uF and 10uF. Although a bit lower I think they will work. Electrolytic capacitors are never close-tolerance components. Finding a single can with the right value in it might be a problem, you may have to replace it with a pair of capacitors or re-stuff the old can (carefully cut it open, extract the guts and fit a pair of modern capacitors inside.)

Philips210 · 15th Mar 2017, 8:50 pm

Quote:

Originally Posted by skamanuk

A followup question if I may. I need to replace the mains smoothing can (picture attached) where would I track this or a modern version of?. The can only has two pins as can be seen by picture 2

Hi.

I wonder whether your HT reservoir/smoothing capacitor really needs to be replaced. Have you tried to reform it? I always avoid replacing this component where possible and in the vast majority of cases they will reform. If it will reform OK then it's more than likely to be fit for service. I'm sure other forum members could give you further advise on this.

Regards
Symon.

crackle · 15th Mar 2017, 8:52 pm

0.039uf 39nf are available in 100v versions, but you need to go to a fairly specialist supplier for 250v ones.
Personally I would use the commonly available 0.047uf for the 0.04uf one as well.

Mike

skamanuk · 16th Mar 2017, 2:05 am

Quote:

Originally Posted by Boater Sam

1, 0.0022uf 2.2nf 2200pf
2, 0.01uf 10nf
3, 0.0047uf 4.7nf 4700pf
4, 0.0047uf 4.7nf 4700pf
5, 0.039uf 39nf

All voltages to be the same as originals or higher.

Thanks for the help. the only versions i can find are 630v quite a lot higher than the originals, are they ok to use

Boater Sam · 16th Mar 2017, 2:30 am

Yes, as I said "or higher"

nicam49 · 21st Mar 2017, 9:04 pm

Hello All, I'm also the proud owner of a Pye BB,- a MK1- though mine sadly has an o/c primary winding on the o/p transformer,- it's not the ultra-linear model - however, I want to crack on with it and replace those Hunts caps before powering it up, but I'm bewildered by the variety of caps available:- Polypropylene, Polyester, ceramic, etc....can anyone please advise what I should use for the best as replacements....thanks!
Nick

Station X · 21st Mar 2017, 10:48 pm

Take a look here:-

https://www.vintage-radio.com/repair...apacitors.html

'LIVEWIRE?' · 21st Mar 2017, 11:21 pm

At the risk of re-stating something I, and no doubt other forum members have mentioned before, modern dual (and triple)can electrolytic capacitors are available from various sources, though I doubt if anyone makes a 12uf capacitor nowadays. In most cases a 16uf replacement will be OK, though the reservoir capacitor, which is directly connected to the cathode of the rectifier, should not exceed the maximum value specified in the data for the valve in question. Stockists of modern 'cans' include Cricklewood Electronics, the BVWS, and www.askjanfirst.de amongst others.

15th Mar 2017, 2:39 pm	#1
skamanuk Retired Dormant Member Join Date: Apr 2013 Location: London, UK. Posts: 245	Replacing capacitors Hi can anybody tell me what modern value capacitors I can safely replace the following with. 1. 0.002uf 350volt 2. 0.01uf 350volt 3. 0.005uf 350volt 4. 0.005uf 150volt 5. 0.04uf 150volt Pye black box amplifier . The above caps are all original HUNTS so need replacing. Gary

15th Mar 2017, 2:58 pm	#2
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Replacing capacitors 1, 0.0022uf 2.2nf 2200pf 2, 0.01uf 10nf 3, 0.0047uf 4.7nf 4700pf 4, 0.0047uf 4.7nf 4700pf 5, 0.039uf 39nf All voltages to be the same as originals or higher.

15th Mar 2017, 5:17 pm	#3
Guest Guest Posts: n/a	Re: Replacing capacitors A frequently asked and not unreasonable question, time for a sticky I think.

15th Mar 2017, 5:21 pm	#4
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Replacing capacitors There is one, but no one ever reads it;- http://www.vintage-radio.net/forum/s...ad.php?t=88767 __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

15th Mar 2017, 6:24 pm	#5
skamanuk Retired Dormant Member Join Date: Apr 2013 Location: London, UK. Posts: 245	Re: Replacing capacitors A followup question if I may. I need to replace the mains smoothing can (picture attached) where would I track this or a modern version of?. The can only has two pins as can be seen by picture 2 Attached Thumbnails

15th Mar 2017, 6:53 pm	#6
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,327	Re: Replacing capacitors The can is earthed. You are unlikely to get a "modern" version of what you have. You will need to buy 2 seperate electrolytic capacitors of similar (or near as) value and at least the same operating voltage. If this is in the smoothng circuit, and it looks like it, you MAY be able to use a 16uf and a 32uf. These may lower the hum level as well. We really need you to provide the make and model number of the unit so it can be can be checked with the circuit diagram. __________________ Edward.

15th Mar 2017, 7:52 pm	#8
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Replacing capacitors That smoothing capacitor is actually 2 capacitors in one can. A 25uF one and a 12uF one rated at 350V each (uF = microfarad). The negative side of each capacitor is connected to the can, and therefore to the metal chassis of the amplifier, the positive sides are connected to the tags. Oriignally one of the tags would have had a red mark on it (possibly on the rivet fixing it to the plastic base of the can), as the writing on the can says that would be the 25uF one, leaving the other tag for the 12uF capacitor. If the mark is no longer present you have to trace where each tag is connected to and compare it with the circuit diagram. That will tell you which is which. The nearest modern equivalents are 22uF and 10uF. Although a bit lower I think they will work. Electrolytic capacitors are never close-tolerance components. Finding a single can with the right value in it might be a problem, you may have to replace it with a pair of capacitors or re-stuff the old can (carefully cut it open, extract the guts and fit a pair of modern capacitors inside.)

15th Mar 2017, 8:52 pm	#10
crackle Rest in Peace Join Date: Mar 2011 Location: Basildon, Essex, UK. Posts: 4,100	Re: Replacing capacitors 0.039uf 39nf are available in 100v versions, but you need to go to a fairly specialist supplier for 250v ones. Personally I would use the commonly available 0.047uf for the 0.04uf one as well. Mike

16th Mar 2017, 2:30 am	#12
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Replacing capacitors Yes, as I said "or higher"

21st Mar 2017, 9:04 pm	#13
nicam49 Hexode Join Date: Aug 2014 Location: Wigston, Leicester, UK. Posts: 350	Re: Replacing capacitors Hello All, I'm also the proud owner of a Pye BB,- a MK1- though mine sadly has an o/c primary winding on the o/p transformer,- it's not the ultra-linear model - however, I want to crack on with it and replace those Hunts caps before powering it up, but I'm bewildered by the variety of caps available:- Polypropylene, Polyester, ceramic, etc....can anyone please advise what I should use for the best as replacements....thanks! Nick

21st Mar 2017, 10:48 pm	#14
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Replacing capacitors Take a look here:- https://www.vintage-radio.com/repair...apacitors.html __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

21st Mar 2017, 11:21 pm	#15
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: Replacing capacitors At the risk of re-stating something I, and no doubt other forum members have mentioned before, modern dual (and triple)can electrolytic capacitors are available from various sources, though I doubt if anyone makes a 12uf capacitor nowadays. In most cases a 16uf replacement will be OK, though the reservoir capacitor, which is directly connected to the cathode of the rectifier, should not exceed the maximum value specified in the data for the valve in question. Stockists of modern 'cans' include Cricklewood Electronics, the BVWS, and www.askjanfirst.de amongst others.