Cub Conversion

Although YSTV broadcast in Colour from 1986 onwards, many of the monitors in the control room were still black and white, with only a few key output monitors displaying colour. This along with the mixed sizes of monitor made mounting them into the mixed collection of wooden shelving difficult. It also made it hard to know what the on-air picture would look like until it got there, by which time it was too late.

By the late 1990s the large numbers of BBC microcomputers supplied to schools were being replaced by PCs as technology marched on. Almost all of these had Microvitec "Cub" monitors with them. These were steel-cased 15" monitors, capable of displaying full colour. The ran at the TV picture size and frame rate (625 lines, 50 Hz), making them idea for displaying video. This had to be the case because the BBC could also be hooked up to a TV if you didn't have a dedicated monitor, as YSTV regularly did for many purposes.

Thus the plan was hatched to create a new monitor bank for the station using 18 of these monitors (three rows of 6) to display all the important live video signals to the control room. The monitors were relatively cheaply and easily available second hand, so accumulating a set was not a problem. The snag was that the model with a composite video input suitable for connection to the studio was almost unheard of, with most purchasers having opted for the basic model with only an RGB input at TTL levels, suitable for connection to a BBC micro but almost nothing else. This problem was solved by the construction of an adaptor board that could be installed into the back of the monitor to perform the decoding of the composite video signal into it's RGB components to be fed into the monitor. The RGB input was disconnected, as they were intended only for use as video monitors.

The innards of the upgrade

This circuit was created by Rob Sprowson, and a set of 18 duly created in 2000 or so?Unverified or incomplete information, together with a new, steel monitor rack sized so that the monitors would fit neatly on it. The station mains wiring was upgraded so that the wall behind the rack had enough mains sockets to plug everything in directly (see the G/046 page for the tale of how this was done]], and YSTV could now see every point of the vision path in colour. The old black and white monitors were cascaded to become part of the NaffoCue system.

Although a very good idea, the Cub monitors were not designed or built for a log life, getting very hot in use (they have been seen in use as Pizza warmers). Given they were second hand to start with, this lead to a steady rate of failures in the chassis, as well as problems with the stability of the converter boards themselves.

By 2003 this frequently lead to monitors that were drastically too bright, too dark or the wrong colour, and several of which whistled even when there was a video input (almost all whistle without one). This lead to a steady campaign (lead by Rowan de Pomerai) to get the monitor rack upgraded to something that actually showed accurate pictures. After much debate, deliberation and experimentation this was achieved in 2006 by the use of the VGA Converter Boxes, allowing the worst of the cub monitors to be scrapped and the remainder relegated to secondary use on OBs and loans to other people.