[ChristianFletcher]

I’m just starting my second television restoration on a Murphy Type 350. I haven’t changed out Any components as yet. The set had the selenium rectifier replaced with a silicon diode by the previous own and I have reformed the electrolytic and brought the set up on a variac. The set had slightly high HT due probably due to the use of the silicon diode. I have just over 10kv to the picture tube anode.

The picture is static and does have very solid horizontal and vertical hold. Has very poor volume when fed from the standard converter signal source.

So with a test card input I see only the top half the screen with the bottom lines finally compressed into a white line. When starting to search for information on this type of thing it’s probably important to get the terminology and description of the problem accurately described. So my first question is this what is called a collapsed frame.

So I’m thinking that this problem is caused by lack of drive to the frame scan coils so where should I start to diagnose the frame collapse from. I am thinking I should probably check I have the 500v boost voltage. Is it safe to measure the boost voltage without cremating the volt meter. What is the effect of having a low boost voltage.

My next checks would probably be to check the voltage around frame amplifier and frame output valve. I am wondering why the frame is collapsed in a none linearly fashion in my mind it should be equally collapsed about a central horizontal line ?

Note on the picture they are upside down the lower part of the screen is black

Thanks for any advice regards Chris