UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Offered and Wanted Messages > Sets, Parts and Service Information Wanted (private buyers only, no swaps)

Notices

Sets, Parts and Service Information Wanted (private buyers only, no swaps) If you need help obtaining components, sets or equipment, post a message here. Private buyers only - no traders. No swaps.

Closed Thread
 
Thread Tools
Old 25th Jan 2022, 7:37 pm   #1
Helder Crespo
Hexode
 
Helder Crespo's Avatar
 
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 343
Default Lemco dogbone capacitors

Hi
I wonder if anyone has Lemco dogbone capacitors, 3000pF (Hi-K series, 500 or 750V) like the one in the photo. I'm looking for 10 more of these for an RF section.
Many thanks
Helder
Attached Thumbnails
Click image for larger version

Name:	IMG_1411.jpg
Views:	156
Size:	119.5 KB
ID:	250482  
Helder Crespo is offline  
Old 26th Jan 2022, 10:28 am   #2
G6ONEDave
Octode
 
G6ONEDave's Avatar
 
Join Date: Dec 2019
Location: Owston Ferry, North Lincolnshire, UK.
Posts: 1,117
Default Re: Lemco dogbone capacitors

Hi Helder,
I have some 3nf tubular capacitors that are similar to your Lemco one. These are light brown in colour and measure approx 17mm long x 4.5mm dia, they don't have any voltage stated on them. Having tested a couple they measure 2583pf and 2658pf which if at 20% tolerance are a bit low but still in tolerance. I can send you 20 of them for cost of post, PM me if it is of help.

Dave
__________________
Quote "All is hyperthetical, until it isn't!" (President Laura Roslin, Battleship Galactica)
G6ONEDave is offline  
Old 26th Jan 2022, 12:05 pm   #3
Longespee
Pentode
 
Join Date: Jun 2009
Location: Leominster, Herefordshire, UK.
Posts: 198
Default Re: Lemco dogbone capacitors

Hi Helder,
I may have some, let me check, although I get the feeling they are 1000pf.

I'm looking for some at 500pf in the same style, but they do seem quite difficult to pin down.

Sean.
Longespee is offline  
Old 26th Jan 2022, 12:10 pm   #4
vidjoman
Nonode
 
Join Date: Jun 2013
Location: East Sussex, UK.
Posts: 2,928
Default Re: Lemco dogbone capacitors

Think these were also sold by Radiospares back in time so might find them with the RS logo on.
vidjoman is online now  
Old 26th Jan 2022, 12:17 pm   #5
Helder Crespo
Hexode
 
Helder Crespo's Avatar
 
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 343
Default Re: Lemco dogbone capacitors

Quote:
Originally Posted by G6ONEDave View Post
Hi Helder,
I have some 3nf tubular capacitors that are similar to your Lemco one. These are light brown in colour and measure approx 17mm long x 4.5mm dia, they don't have any voltage stated on them. Having tested a couple they measure 2583pf and 2658pf which if at 20% tolerance are a bit low but still in tolerance. I can send you 20 of them for cost of post, PM me if it is of help.

Dave
Thanks Dave, that's very kind of you. I will take your offer in case I can't get the later make epoxy coated red ones.
Helder
Helder Crespo is offline  
Old 26th Jan 2022, 12:24 pm   #6
Helder Crespo
Hexode
 
Helder Crespo's Avatar
 
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 343
Default Re: Lemco dogbone capacitors

Quote:
Originally Posted by Longespee View Post
Hi Helder,
I may have some, let me check, although I get the feeling they are 1000pf.

I'm looking for some at 500pf in the same style, but they do seem quite difficult to pin down.

Sean.
Thanks Sean. I also think they're hard to find which is why I'm now trying with the forum after a long period of fruitless online searches. You can get 1000pF and 2000pF on eBay right now, but I've never seen 3000pF ones.
I checked my small stock of these, but unfortunately I don't have any 500pF. I have 1x1500pF, 2x2000pF (one of them RS marked) and 3x1000pF, in case you're interested.
Helder
Helder Crespo is offline  
Old 26th Jan 2022, 12:49 pm   #7
Helder Crespo
Hexode
 
Helder Crespo's Avatar
 
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 343
Default Re: Lemco dogbone capacitors

Quote:
Originally Posted by vidjoman View Post
Think these were also sold by Radiospares back in time so might find them with the RS logo on.
Yes, I have seen them with several different markings, including RS. Thanks.
Helder Crespo is offline  
Old 26th Jan 2022, 12:55 pm   #8
Longespee
Pentode
 
Join Date: Jun 2009
Location: Leominster, Herefordshire, UK.
Posts: 198
Default Re: Lemco dogbone capacitors

Quote:
Originally Posted by Helder Crespo View Post
Quote:
Originally Posted by Longespee View Post
Hi Helder,
I may have some, let me check, although I get the feeling they are 1000pf.

I'm looking for some at 500pf in the same style, but they do seem quite difficult to pin down.

Sean.
Thanks Sean. I also think they're hard to find which is why I'm now trying with the forum after a long period of fruitless online searches. You can get 1000pF and 2000pF on eBay right now, but I've never seen 3000pF ones.
I checked my small stock of these, but unfortunately I don't have any 500pF. I have 1x1500pF, 2x2000pF (one of them RS marked) and 3x1000pF, in case you're interested.
Helder
Thanks Helder, I just had a look and they are a mix of 1000pf and 2000pf.
Thank you for looking, very kind. This particular project will also allow me to use the Lemco/RS 500pf Mica rectangles, but even so these are still hard to find.

Sean.
Longespee is offline  
Old 26th Jan 2022, 1:19 pm   #9
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 19,990
Default Re: Lemco dogbone capacitors

Better known as tubular ceramics. They've stood the test of time quite well.

There were 'High-k' ones in the 1000pF region, as well as low tempco ones in the 1-100pF region.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now  
Old 26th Jan 2022, 1:26 pm   #10
Helder Crespo
Hexode
 
Helder Crespo's Avatar
 
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 343
Default Re: Lemco dogbone capacitors

Quote:
Originally Posted by Radio Wrangler View Post
Better known as tubular ceramics. They've stood the test of time quite well.

There were 'High-k' ones in the 1000pF region, as well as low tempco ones in the 1-100pF region.

David
Thanks David. In my searches I have been using both terms (dogbone and tubular ceramic). Still hard to find. They do seem to be quite robust, and I've read elsewhere that the only time someone found a faulty one this was due to mechanical breakage. However, they do seem to be a bit on the low side nowadays. Usually still within tolerance, but low nevertheless. Perhaps some degradation/oxidation in the metallic coating over time in spite of the epoxy coating, e.g. due to trapped residual contaminants.
Helder
Helder Crespo is offline  
Old 26th Jan 2022, 2:06 pm   #11
Helder Crespo
Hexode
 
Helder Crespo's Avatar
 
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 343
Default Re: Lemco dogbone capacitors

On the other hand, the High-K ones have a rather large positive temperature coefficient, and their capacity increases by 10-20% for a temperature change of only a few degrees. So perhaps they were designed for an operating temperature slightly above room temp. Just guessing here.
Helder
Helder Crespo is offline  
Old 1st Feb 2022, 8:12 pm   #12
Helder Crespo
Hexode
 
Helder Crespo's Avatar
 
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 343
Default Re: Lemco dogbone capacitors

I got a great set of 3000pF capacitors from Dave today, so this thread can be closed.
Many thanks,
Helder
Helder Crespo is offline  
Closed Thread

Thread Tools



All times are GMT. The time now is 8:39 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.