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{{HDNO}} | |||
{{Outofdate}} | |||
The | The '''''main mux''''' is the huge black thing in the [[AV rack]]. It routes video to different places, and also has analogue TV demodulator inputs. It's controlled by an outboard box which sits on the Director/Vision Mixer's desk. | ||
==Functions== | |||
* 32 input to 4 output matrix | * 32 input to 4 output matrix | ||
==Faults== | ==Faults & unknowns== | ||
2 composite inputs to the matrix are dead. | *2 composite inputs to the matrix are dead. | ||
*Input 23 ad 32 are dodgy. | |||
== | ==Explanation of operation== | ||
This was originally based around a PIC16F84 with an 8MHz crystal containing code written by [[hist:Rob Sprowson|Rob Sprowson]], the code for which is now lost. | |||
'' | A new PIC, a PIC18F2455 using a 20MHz crystal, has replaced this PIC through use of an extra 'daughter' board. This change in PIC was to allow easier coding, using C instead of assembler, and to provide USB capabilities. The source code has also been lost. | ||
It now runs on an installed Arduino, and is one of the first [[YVP_Protocol|YVP Protocol]] compatible devices. This does mean a computer is needed to control it however, connected to the now real, RS-232 compliant serial port on the back. | |||
==Power supply== | |||
This is very much the weak point of the mux, and is tied up with why there are loads of unconnected [[BNC]]s on the back. - The Mux used to hold a distribution amplifier for creating 8 outputs of each main output from the matrix. Sadly though, this experienced some heavy cross-talk, and was misdiagnosed as "electric fields". The original creators now propose that simply adding better decoupling to the power supply would have solved the problem. | |||
There are two mains transformers: | |||
* 2x6V | |||
**50VA | |||
**powers + and - 5V rails | |||
*2x6V | |||
**3VA | |||
**wired as 1x12V, 3VA to provide the +12V rail. | |||
All the supplies are smoothed with big electrolitics, and then regulated with 78/79 series regulators. | |||
All this is built on a length of chocolate block connector strip, with a lot of stranded hookup wire. | |||
[[Category:Vision Path]] | |||
[[Category:Home-Made]] |