Museum of the Broadcast Television Camera

Question & answer

Pye Lynx Camera

I was asked "What is your opinion on the performance of these cameras?"

Hmmmm a tricky question, in a nutshell, satisfactory would be a quick answer. There are, as always, a number of caveats.

When making comparisons always compare like with like. The Lynx was well designed and built to last as your camera proves as it must be about 45 years old! It was in the first generation of the fit and forget surveillance camera's design class, its valve predecessors needing constant "tweaking". The comparable product from EMI was not as well build inside and Marconi cameras were aimed more at the military and broadcast market with prices to match! Cameras were also available from the USA and the continent ( RCA, Dage, Grundig, etc.).

The performance of a vidicon camera depends to a very large extent on the tube. Vidicon tubes were selected for target blemishes, resolution, microphonic, sensitivity, lag, black level shading, the list goes on....

EMI offered at least 7 grades of tubes:-
Premium grade, 1st grade, commercial grade, industrial grade, low cost CCTV, X-ray applications, there was also an unlisted "amateur grade" tubes or rejects! I understand that the cheapest "amateur" grade was about £12 in the early 1970s.

Pye normally used tubes made by Cathodeon, with was, I understand, part of the Pye group of companies. The vidicon tubes were branded "Staticons" and early tubes had an unusual "evacuation pip" on the side of the tube adjacent to the target contact ring. This meant that Pye cameras had a slot in the yoke at the front to accommodate this "Pip". Tubes from other manufacturers would, of course fit, but not necessarily vice versa.

The next big determining factor is the scanning yoke. This controls the precision of the geometry of the raster and focus. The electronics also play a part in this but the yoke is the big cost item. Again the yoke in the Lynx is satisfactory for it's application as a CCTV camera.

The lynx has the advantage of a modulator for direct connection to a TV, a band I set. Also I see your has the six pin connector for remote control of the beam and target voltages.

The target voltage affects the sensitivity of the tube. This voltage is automatically controlled in the later automatic versions of the Lynx to give a degree of control over changing light levels. It should be set to no higher than needed as the lag and other defects gets worse as the voltage increases.

The beam control should be set to "just discharge the picture". When the beam control is at minimum the tube is cut off and as the control is advanced the beam current will start to discharge the target and the picture will appear though a sort of "puddle" of whiteness. The correct setting is when the picture is fully discharged and no more. If there is too much beam current the picture will loose resolution and will take on a "flat" look.

If you have access to a number of tubes it would be well worth while selecting the best of them, the tube is the one thing that has the most effect on picture quality.

Useful info:-
Circuit Diagram for Lynx cameras, TVC1A, to serial No. 1158
Appendix A, 405 line component values & mods.
F.E.T. Lynx Brochure
Practical Television, December 1968 pages 130 & 131, described the Pye Lynx

Regards

Brian