Electronic Circuits and Projects Forum

check your degaussing coil circuit, you should hear a "thwang" sound when the set is turned on

when i turn it on i hear what could be considered a twang and then static on the screen as it turns on s oi assume thats what you mean

I would say the degaussing circuit is up the kyber...

Replace the positor, the little three legged box prior to the mains bridge, the coil that goes round the tube is attached to it if you follow the circuit. Make sure the set is unplugged from the mains before doing anything, and be very careful of charged capacitors. It might be prudent to stick a 100K resistor, with insulated leads, across the main ones in the power supply for a few secs each before you do anything else, just to be sure they are discharged. A nasty crack from the main smoothing block can easily kill a smps or worse, not to mention give you a new hairdoo.

avoid external magnetization, it can cause those color patches. you need a degaussing coil used by technicians to remove color patches, its stronger than the one in your tv

ooooh...lovely...a real live sony scan yoke in yer hands...
the static alone will frighten you as ya go near it...

The last one I done was about 6-7 years ago, and the damned anode cap fell out in the middle of the procedure...started jumping about arcing here and there etc....was frighteningly funny to watch according to my collegues...
The set survived, but I needed my purity adjusted afterwards...

I do agree though, loads of the sony's I have worked on suffered from purity problems due to the scan yoke moving about, it just didn't sound like it was this from what johnny69 posted.

Of course nobody mentioned that if he does play with the scan yoke, without a pattern generator, the tube set-up is unlikely ever to be close again. And in the case of a trinitron, a handful of those daft permalloy magnets won't go amiss either