PHILIPS IF transformers

Once in a while I stumble over Philips IF cans with the coil open or the tiny ferrite core inside the plastic tube witch is the coil form stucked.

I wonder if someone has a good method to restore those transformers.

Here are some pictures are pictures of the type:

 

Attachments:

• IF can in the radio (57 KB)
• IF can dismantled (58 KB)

To thank the Author because you find the post helpful or well done.

Hello,

perhaps you can get help here or here. In the second link, Post 5, you can read how to repair a loose ferrite without dismatling the filter from the chassis.

Andreas

To thank the Author because you find the post helpful or well done.

Certainly!!!

But unfortunately I dont understand german language.

I'll try to use a online translator to see the article.

Thanks anyway.

Meyer

To thank the Author because you find the post helpful or well done.

Hello,

if you are not successfull with an online-transformer, then we should find another solution, because these articles show basic facts and are very helpfull.

Andreas

To thank the Author because you find the post helpful or well done.

Hello Meyer,

A small thread is HERE,  in English!

And HERE.

Roy

To thank the Author because you find the post helpful or well done.

Dear Andreas and Roy,

Thanks for your efforts to help me with this matter.

I made a satisfactory translation at Google's page:

http://translate.google.com/translate_t#web:de|pt|http%3A%2F%2F

It's very useful tool for us here in this forum.

My best wishes for all.

P.S. now I'll put my hands to work with my bad IF transformer.

To thank the Author because you find the post helpful or well done.

  When my Philips AM IFT are out of function. I disassembly IFT cans checking coils and find one coil are internal open by 4 sections, even rewind by cross wiring methode, the bigger coil size make Q value drop to low selectivity and sensitivity.

  Then I give up  repair original IFT and using Japanese TRIO brand IFT-B (IF output stage) substitute for Philips.  Plate. B+. Grid. Earth. 4 terminals connect to respective positions as short as possible. It is function well as original Philips IFT, and only need a little bit adjustment ferrite screw from 455KHz down to 452KHz, and find a space that use hot glue to fix new one on it. This my lazy way to fight against Philips AM IFT!

Best Regards

Don

 

To thank the Author because you find the post helpful or well done.

Having said that, I have bougth 5 Philettas (two 273, two 263 and one 254): three of them have the same IF problem. I have not yet solved it.

To thank the Author because you find the post helpful or well done.

In my case, the ferrite core was so badly stuck that the winding and plastic tube had to be discarded. 

1. The core was re-attached to the brass adjustment ferrule using epoxy.

2. The plastic former was replaced using a small length of plastic drinking straw of the same diameter as the original.

3. The windings were replaced with a 46 S.W.G silk-covered wire by winding in a criss-cross pattern. The idea being to reduce the self-capacitance of the windings as much as possible. Using a silk or cotton covered wire assists by spacing the wire conductor further apart than enamel covered wire. Because the windings are so tiny, you may be able to salvage some silk or cotton covered wire from an old IF transformer, although its much better to buy new if you can.

4. The transformer was re-assembled and re-tuned. It seems to work perfectly.

5. Alas, my attempts with new IF transformer windings for an Eddystone 940 haven't been quite as successful. (A previous owner had removed the original IF coils in their entirety. - Long story). Here the problem is getting the spacing between the primary and secondary correct, as well as getting a high Q. The selectivity is almost, but not quite right.

6.Also look at http://www.qsl.net/k5bcq/COIL/COIL.html . I must make one of these.

Good luck - Bryce

 

To thank the Author because you find the post helpful or well done.