IFTransformers

Dear Don,

I wonder if this problem I had with jammed IF transformer cores and how I overcame it might be of interest to other readers who might have a similar problem?

On my Wireless 19 Set I felt that the IF and input coils might need adjusting, it’s still a bit deaf. So much was wrong with it when I first got it that they could need some adjustment. I removed the wax and turned the green threaded portion only for it to keep turning with no change in received signals.

On removing the screening can I found the green threaded part had broken off from the ferrite core. Only one ferrite came free with its green threaded adjuster. I tried super-gluing a short piece of plastic between the ferrite core and green part but it broke off again in the coil former when I screwed it in. It would have to be perfectly central and not off at an angle. It wasn’t, which is why it broke the very top off the ferrite. Do I go online to look for some more IF transformers and aerial input coils, if available? I could just buy the same problem again.

I abandoned the idea of screwing them in and got some pieces of plastic slightly smaller diameter than the ferrites, cut them to about one inch in length and super-glued them to the cores. I could now push the ferrites in and out of the cores but they were too long to put the chassis back into the cabinet. I tried cutting one down but didn’t have enough to grip to pull it out again. I tried long nose pliers but pushed it further in. The set was working quite nicely now but how to pull them out if I pushed them in too far without leaving them too long?

My solution was to glue a small length of cotton to the plastic, which I could pull the core back out if it went in too far. To help it to stay in place I used a small hacksaw to cut into the plastic to make a groove to tie the cotton into and super glue it. On all six coil formers I had to roll up a piece of sandpaper and work it inside the coil former to enlarge the inside so the cores would run freely. They were so tight I originally thought they had been glued. I guess over 71 years the formers had shrunk resulting in gripping the ferrite cores tightly. Two formers were loose in the coils so I fixed those into position with candle wax.

The photo shows the original green adjuster, which didn’t break off, although it’s a bit tight, two ferrite cores with long plastic pieces and at top left is the shorter plastic piece with a length of cotton attached. At the bottom is a ferrite core with the long plastic glued on. The final job is to slightly lean the set forward and tune all six cores then drop some melted candle wax into the top of the cores to seal the plastic that hold the ferrites in place.

Not yet though because I want to try a Q Multiplier from a circuit I found in PW, December 1966 for an R1155 set and it says the first IF cores need re-aligning. Although the article is for the R1155 with an IF of 560kc/s details are given for an IF of 465kc/s. Bill Kitchen G4GHB.

Ashton under Lyne