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Old 7th Mar 2021, 8:55 pm   #3
KeithsTV
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Join Date: Aug 2007
Location: South Bradford, West Yorkshire, UK.
Posts: 2,571
Default Re: Need an Isolation Transformer for CTX-S (Philips 14CT2006)

That article brings back memories as it's around 30 years since I wrote it! At the time toroidal isolation transformers were readily available but are few and far between these days. The reason for using a toroidal transformer is the low external magnetic field as I mounted the transformer inside the TV. The stray magnetic field from a conventional transformer mounted internally would affect the CRT too much. If you can't get a toroidal transformer it would be best to mount the isolation transformer, such as the one suggested, externally. You could try asking Ed Dinning or Mike Barker if they could wind a suitable transformer although I don't think they can wind toroidal transformers.

If you are only using it as a video input then most of the circuit relating to video and audio out can be omitted. The components around TR5 and IC2c & d can be omitted and IC2 replaced by a dual op amp such as a TL072.

Incidentally I still have the TV I used to design the interface which gets used occasionally.

Keith
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