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

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Test Gear and Workshop Equipment

Notices

Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders.

Closed Thread
 
Thread Tools
Old 10th Apr 2011, 10:26 am   #1
SM6FBY1
Diode
 
Join Date: Apr 2011
Location: Molndal Sweden
Posts: 1
Default "hf fuse" for sg output protection

Hello, I am looking for the external N-plug with a built in fuse that HP and Marconi used at the output of their signalgenerators for attenuator protection. Does anybody know where the plugs and fuses can be bought today?
73 de SM6FBY Bengt
SM6FBY1 is offline  
Old 10th Apr 2011, 1:51 pm   #2
Stockden
Hexode
 
Join Date: Mar 2008
Location: Forest of Dean, Gloucestershire, UK.
Posts: 491
Default Re: "hf fuse" for sg output protection

Well, the plug assemblies sometimes appear on eBay, which is where I bought mine from. Sadly the cartridge fuses to go inside seem to be unobtainable.
Stockden is online now  
Old 10th Apr 2011, 2:17 pm   #3
neon indicator
No Longer a Member
 
Join Date: Jun 2010
Location: Co. Limerick, Ireland.
Posts: 1,183
Default Re: "hf fuse" for sg output protection

That would be nice on my 8555 18GHz spectrum Analyser plugin on HP141T.

Though would the fuse blow faster than the mixer on the 1mW range ?
neon indicator is offline  
Old 12th Apr 2011, 9:03 pm   #4
robinshack
Octode
 
robinshack's Avatar
 
Join Date: Jun 2010
Location: Spalding, Peterborough, Cambridgeshire, UK.
Posts: 1,167
Default Re: "hf fuse" for sg output protection

Hello, an easier/more reliable alternative may be a 20dB or 30dB 1GHz (or suitable freq) power attenuator, rated at say 25W. May be worth considering?
I used to use a 20dB 25W (N type) attenuator permanently attached to my sig gen output. It was accurate (in dB) and many times paid for itself in protecting the sig gen. In fact, testing 25W VHF transceivers, I would often repeatably toggle between tx and rx whilst looking for intermittant antenna relay faults!
Like a previous post, the fuses (Littlefuse?) were hard to find.
73, Robin
robinshack is online now  
Old 13th Apr 2011, 5:53 pm   #5
Stockden
Hexode
 
Join Date: Mar 2008
Location: Forest of Dean, Gloucestershire, UK.
Posts: 491
Default Re: "hf fuse" for sg output protection

Actually, these seem easier to find than I thought. There's an example of the N connector version (TM5753) on eBay UK at the moment and there's examples of both the BNC connector version (TM9884) and an HP N connector equivalent (all with spare fuses!) here.

The fuses are 1/16A (62.5mA) produced by littelfuse, though my bit of paper with the type number on seems to have been mislaid. However short, fat fuses (1"-ish long but same diameter as 1.25" fuses iirc) rated at 62.5mA, as Robin says, aren't easy to find!

Having said that, I also agree with robin's point about using an attenuator.

Hugh

Last edited by Stockden; 13th Apr 2011 at 5:55 pm. Reason: Incompetence!
Stockden is online now  
Old 13th Apr 2011, 6:01 pm   #6
Herald1360
Dekatron
 
Herald1360's Avatar
 
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 14,521
Default Re: "hf fuse" for sg output protection

Aren't 20mm 63mA fuses readily sourced? A simple adaptor (or just a bit of spring) should take care of the fitting........
__________________
....__________
....|____||__|__\_____
.=.| _---\__|__|_---_|.
.........O..Chris....O
Herald1360 is offline  
Old 14th Apr 2011, 5:57 pm   #7
Stockden
Hexode
 
Join Date: Mar 2008
Location: Forest of Dean, Gloucestershire, UK.
Posts: 491
Default Re: "hf fuse" for sg output protection

Indeed they are, thank you for reminding me.

Unfortunately, because of the way the fuse is mounted, replacing the 25x6.3mm original with a 20x5mm fuse needs a little bit more than a spring as the fuse "ends" need to be increased in both length and girth. The photos below illustrate what I mean.

Still, it's clearly not impossible and I've been toying with the idea of drilling a 5mm hole through the middle of an old (metal) pot spindle. One day I might actually get round to doing something about it!
Attached Thumbnails
Click image for larger version

Name:	1.jpg
Views:	98
Size:	21.3 KB
ID:	49534   Click image for larger version

Name:	2.jpg
Views:	84
Size:	25.1 KB
ID:	49535  
Stockden is online now  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 7:35 am.


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 - 2020, vBulletin Solutions, Inc.
Copyright ©2002 - 2020, Paul Stenning.