Cossor 368 'Reaction' Receiver - 1935 - UK Vintage Radio Repair and Restoration Discussion Forum

27th Jul 2004, 6:44 pm

I recently bought the above set and began restoration on the set.

It needed the usual new condensers throughout (not a huge number for this set) and both low voltage electrolytics had gone very mouldy, after the condensers had all been replaced a new mains lead was fitted and also new speaker leads as these were very rotten.

There were then 2 slightly more fiddley problems to resolve.

Firstly, the dial cord was broken, however, when trying to remove the cursor from the original cord very gently two of the securing lugs just fell off, they were very brittle. It took a while to find a solution to this, but I cleaned up the back of the cursor and discovered that it was made of brass. I cut some wire ends from some old condensers and folded two over, I soldered one to each side of the cursor, this then allowed it to be re-attached to the dial cord and it travelled back and forth across the dial as it should.

The second problem was the switching mechanism. This goes from the front to the back of the chassis and was very corroded and dirty. I discovered that a spring held one end in place whilst a small bracket held in the other end. I removed the spring and the bracked and I was able to carefully withdraw the entire switching barrell.

Firstly I gently cleaned up the sprung contacts on the chassis with fine emery paper. I then examined the switch barrell and discovered that the switching was performed by numerous 'staples' around the perimeter of the barrell.

Each one of these 'staples' was cleaned with fine emery paper and then both the contacts on the chassis and the 'staples' were all given a spray of servisol. The barrell was then gently placed back in between the switch contacts and secured in to place.

The set was then powered up and worked perfectly, very sensative. It's nice to use an old reaction set, they take a bit of twiddling to tune in but this one is amazingly sensative. The faults were not major, just fiddley, but it was well worth the effort.

grindrod · 15th Apr 2005, 11:42 am

TRF's are great fun, I always regret selling a Burgoyne Hollywood AC3!

As brass ages it becomes crystaline and very brittle, I used to have an old Philips extension speaker that I used when I was a youngster making radios in the 60's and early 70's.

However, last year I found it in my Dad's loft and was shocked to find that the three brass 2BA bolts that held the magnet assembly to the speaker chassis had all failed!! The magnet had fallen off and ripped the coil to pieces.

If anyone has something similar I strongly suggest that they don't trust 70 year old brass nuts and bolts, especially if failure could have catastrophic consequences!!

Cheers, Martin

27th Jul 2004, 6:44 pm	#1
fableglade Guest Posts: n/a	Cossor 368 'Reaction' Receiver - 1935 I recently bought the above set and began restoration on the set. It needed the usual new condensers throughout (not a huge number for this set) and both low voltage electrolytics had gone very mouldy, after the condensers had all been replaced a new mains lead was fitted and also new speaker leads as these were very rotten. There were then 2 slightly more fiddley problems to resolve. Firstly, the dial cord was broken, however, when trying to remove the cursor from the original cord very gently two of the securing lugs just fell off, they were very brittle. It took a while to find a solution to this, but I cleaned up the back of the cursor and discovered that it was made of brass. I cut some wire ends from some old condensers and folded two over, I soldered one to each side of the cursor, this then allowed it to be re-attached to the dial cord and it travelled back and forth across the dial as it should. The second problem was the switching mechanism. This goes from the front to the back of the chassis and was very corroded and dirty. I discovered that a spring held one end in place whilst a small bracket held in the other end. I removed the spring and the bracked and I was able to carefully withdraw the entire switching barrell. Firstly I gently cleaned up the sprung contacts on the chassis with fine emery paper. I then examined the switch barrell and discovered that the switching was performed by numerous 'staples' around the perimeter of the barrell. Each one of these 'staples' was cleaned with fine emery paper and then both the contacts on the chassis and the 'staples' were all given a spray of servisol. The barrell was then gently placed back in between the switch contacts and secured in to place. The set was then powered up and worked perfectly, very sensative. It's nice to use an old reaction set, they take a bit of twiddling to tune in but this one is amazingly sensative. The faults were not major, just fiddley, but it was well worth the effort.

15th Apr 2005, 11:42 am	#2
grindrod Retired Dormant Member Join Date: Feb 2005 Location: Stroud, Gloucestershire, UK. Posts: 57	Re: Cossor 368 'Reaction' Receiver - 1935 TRF's are great fun, I always regret selling a Burgoyne Hollywood AC3! As brass ages it becomes crystaline and very brittle, I used to have an old Philips extension speaker that I used when I was a youngster making radios in the 60's and early 70's. However, last year I found it in my Dad's loft and was shocked to find that the three brass 2BA bolts that held the magnet assembly to the speaker chassis had all failed!! The magnet had fallen off and ripped the coil to pieces. If anyone has something similar I strongly suggest that they don't trust 70 year old brass nuts and bolts, especially if failure could have catastrophic consequences!! Cheers, Martin