Installing new B7G valve base - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

G6Tanuki · 1st Feb 2020, 7:45 pm

Just Google for "PTFE B7G valve base".

The usual ones are 'skirted' for use with a screening-can, but you don't need to fit a can.

Or https://mullard.org/products/copy-of...ve-bases-b7g-1

and look at the "Amphenol PTFE" option.

I always use either PTFE or Ceramic valveholders when I'm building oscillators and such .

Luxman1050 · 1st Feb 2020, 8:06 pm

Cheers

Chindit · 3rd Feb 2020, 2:38 pm

De-soldering, straightening and removal of each two-fingered 'tine' in turn and replacing them with unused ones taken from a new, old stock valve holder has worked a treat for me on many of my battery sets, including 'biggies' like the ER Sky Emperor and Sky Monarch. No problems since.
You don't even have to fully straighten the replacement ones before you fit them - they will give enough as you push them in place.
As mentioned by many, if left alone, these valve holders are a constant source of poor or non-existent connections, leading to erratic LT voltages and inexplicable failures.
Colin.

bluepilot · 3rd Feb 2020, 6:01 pm

I recently bought a load of "Copper Brass Eyelet Hollow Tubular Rivets Through Nuts Hole Grommets" from a Chinese supplier. They come in all sorts of sizes and lengths.

Luxman1050 · 3rd Feb 2020, 7:24 pm

Cheers Stuart must say quite a response so I've got plenty of ideas to choose from.

clockman · 1st Aug 2020, 11:34 pm

Amazing number of posts to this problem i have located on my ultra twin the third valve base is faulty and i must replace it i have ordered 2 Mcmurdo bases from ebay and i will use nuts as most of you suggest

antenna441 · 27th Aug 2020, 10:04 pm

Just found this thread and thought you might be interested in my approach. I have never changed a complete valve base, in line with what others have said. I have changed many individual connectors. I have a collection of 50+ Attache case radios which seem to suffer badly from fractured forks. I put this down partly to the rigidity of the components closely soldered the valve holder, stressing the connector when valves are changed.
My testing sequence is as follows.... Visual check. o/p transformer check. Valve base check. Complete waxy c change. I'm a just change them and not bother to restuff for the look, sort of person. Testing the valve bases is the problem, so I made a test unit. A 7 way rotary switch and a test lead terminated in a B7G plug. It's really easy to use and the results are reliable. One of my Vidor Regattas required 11 replacement contacts all quickly identified. I attach a picture of my test unit. the difficult part, was sourcing the B7G plug The phrase rare as hens teeth comes to mind.

1st Feb 2020, 7:45 pm	#21
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,998	Re: Installing new B7G valve base Just Google for "PTFE B7G valve base". The usual ones are 'skirted' for use with a screening-can, but you don't need to fit a can. Or https://mullard.org/products/copy-of...ve-bases-b7g-1 and look at the "Amphenol PTFE" option. I always use either PTFE or Ceramic valveholders when I'm building oscillators and such .

1st Feb 2020, 8:06 pm	#22
Luxman1050 Octode Join Date: Apr 2019 Location: Margate, Kent, UK. Posts: 1,728	Re: Installing new B7G valve base Cheers

3rd Feb 2020, 2:38 pm	#23
Chindit Tetrode Join Date: Feb 2011 Location: Bishop Auckland, County Durham, UK. Posts: 97	Re: Installing new B7G valve base De-soldering, straightening and removal of each two-fingered 'tine' in turn and replacing them with unused ones taken from a new, old stock valve holder has worked a treat for me on many of my battery sets, including 'biggies' like the ER Sky Emperor and Sky Monarch. No problems since. You don't even have to fully straighten the replacement ones before you fit them - they will give enough as you push them in place. As mentioned by many, if left alone, these valve holders are a constant source of poor or non-existent connections, leading to erratic LT voltages and inexplicable failures. Colin.

3rd Feb 2020, 6:01 pm	#24
bluepilot Heptode Join Date: Feb 2010 Location: Duffort, Gers, France Posts: 714	Re: Installing new B7G valve base I recently bought a load of "Copper Brass Eyelet Hollow Tubular Rivets Through Nuts Hole Grommets" from a Chinese supplier. They come in all sorts of sizes and lengths. __________________ Stuart The golden age is always yesterday - Asa Briggs

3rd Feb 2020, 7:24 pm	#25
Luxman1050 Octode Join Date: Apr 2019 Location: Margate, Kent, UK. Posts: 1,728	Re: Installing new B7G valve base Cheers Stuart must say quite a response so I've got plenty of ideas to choose from.

1st Aug 2020, 11:34 pm	#26
clockman Pentode Join Date: Jul 2020 Location: Borehamwood, Hertfordshire, UK. Posts: 216	Re: Installing new B7G valve base Amazing number of posts to this problem i have located on my ultra twin the third valve base is faulty and i must replace it i have ordered 2 Mcmurdo bases from ebay and i will use nuts as most of you suggest

27th Aug 2020, 10:04 pm	#27
antenna441 Tetrode Join Date: Aug 2007 Location: Northampton, Northants. UK. Posts: 61	Re: Installing new B7G valve base Just found this thread and thought you might be interested in my approach. I have never changed a complete valve base, in line with what others have said. I have changed many individual connectors. I have a collection of 50+ Attache case radios which seem to suffer badly from fractured forks. I put this down partly to the rigidity of the components closely soldered the valve holder, stressing the connector when valves are changed. My testing sequence is as follows.... Visual check. o/p transformer check. Valve base check. Complete waxy c change. I'm a just change them and not bother to restuff for the look, sort of person. Testing the valve bases is the problem, so I made a test unit. A 7 way rotary switch and a test lead terminated in a B7G plug. It's really easy to use and the results are reliable. One of my Vidor Regattas required 11 replacement contacts all quickly identified. I attach a picture of my test unit. the difficult part, was sourcing the B7G plug The phrase rare as hens teeth comes to mind. Attached Thumbnails