Wednesday, 17 June 2015

Teardown: Professional 1980s Digital Video Effects [DVE] Processor

This is a teardown feature of two units that form a professional grade video effects system from the late 1980s.

The two devices in question are the CEL Electronics P152B Universal Touch Screen Controller which is clearly designed to be mounted into a video editing desk/studio and it's processor which is the CEL Electronics P164 Model 38XP Digital Effects Framestore - TBC designed to be rack mounted. Clearly intended to be used in high-end professional installations.

CEL Electronics which was a UK Limited company does not appear to exist any more but the name does seem to be owned by a company called Snell Group (which is part of Quantel), which does manufacture hardware and software solutions for the broadcast & video production industry. Unfortunately there is very little information available on the internet for these two old devices or even the company CEL Electronics. There are mentions of the company on a few wiki pages relating to video processing and devices but as of writing there is only one page that has any information at all: P152B Information & P164 Information.

From what i can understand the P152B is a universal controller, which is why the legend on the panel only refers to basic functions, the system needs to be booted with system disks (3.5" floppy disks) for the specific device it is to control, in this case the P164. Without these disks the system is essentially non-functional. Sadly i wasn't given anything other than the two units when i bought this so i am unable to make any thing work at the moment.

CEL Electronics P164 38XP Digital Effects Framestore - TBC
This rack mountable unit is clearly the main processor for the system, at the back there are 75ohm BNC connections for what appears to be four video inputs and outputs including additional I/O for syncs, chroma keying, component and composite outputs. There are also several multiway 'D' connectors, their use unknown.

At the front there is an access panel with ventilation guard, behind this are the eleven plug in PCBs which appear to be separated into analog (right) and digital sections (left) which plug into a backplane. Behind this is a switch mode power supply and output connector panels.

It is difficult to determine the exact purpose of each PCB and what capabilities the system has but here i will look at each board in turn and see if we can figure some of this out. Essentially it will digitize incoming video, process it and then output the results back out to analog video so the system will essentially flow as:  Inputs > ADC > Processing > DAC > Outputs.

This is not like the famed Quantel Paintbox, but (i believe) rather a hardware device for basic transitions, fades, wipes and maybe chroma keying, pan & zoom etc. I also understand it can be used for format conversion, ie NTSC to PAL etc.

CEL P164 Rear Panel

SPF1 Board.
The screen print indicates this is processing some of the Chroma information. There are eight large custom CEL ASICs named 'CEL KABOC'.

SPF2 Board.
Similar board to SPF1 but this time operating on the Luminance, with the same ASICs as the SPF1 board.

FSM Board.
There are two identical boards like this. Clearly FSM is Frame Store Memory. The DRAMs are Goldstar 256k by 4 bit devices with 16 devices in each bank with a total of 4 banks over the two boards. This totals 2 MBytes RAM for the system. The DRAM controllers are custom marked with CEL but also with the National Semiconductor logo so maybe a custom part.

BBO2 Board.
Not much to go on with this board, mostly populated with 74 series logic and custom PAL/GAL devices with another custom CEL ASIC labelled 'SX-8'

IOT Board.
This board is likely some kind of IO control, maybe interpreting the commands & data from the P152B and the various ports on the back.

CPU Board.
No prizes for guessing this one, with the title CPU is clearly some kind of main processing board. There is a TI TMS 320C25FN DSP with external SRAM and EPROMs. Some of the SRAM is unpopulated so can probably be upgraded. A Rockwell R65C52P device is a dual communications interface.

PM1 Board.
Although this appears on the analog side of the system is does seem to be digital in nature, a good dose of 74 series logic and two large IDT 71325A55P 2KByte dual port SRAMs with 3 more of the CEL KABOC ASICs. Maybe this is some kind of buffer RAM?

BIM Board.
Just a blank spacer board. The BIM is Built-In-Mixer and is an option for the CEL P164 not fitted to my unit.

IVI Board.
No idea on this one!

ADC Board.
The Analog To Digital Conversion board, three Exar MP7684 8 bit 20Msps ADCs. This is in the ADC board to convert the analog composite and component video inputs to digital. I would say this would be one ADC for the YUV component video channels. Notice the large number of adjustment pots and varicaps, also the analog delay lines in the green and black rectangles, you can see how  these work in EEVBlog Episode #381.

ENC Board.
The counterpart to the ADC board, with 3 TRW 1016N7C8 Video DACs to provide composite and component YUV video outputs. Again like the ADC board there are many adjustments!!

CEL Electronics P152-B Universal Touch Screen Controller
This is the controller of the system, although it appears to be rack mountable i dont believe thats how it would have been installed. From an ergonomics point of view i think this would be installed face up in a video editing desk to allow easy use of the faders and the joystick. My assumption is you can create an effects program here which is processed by the P164 unit.

The P152 appears to be generic in nature and probably was a controller for several different systems, the legend on the front only gives basic ideas of the functions. On power up it tries to read the floppy disk and reports no disk found so i would expect a program for each of the processing units this can operate can be loaded in as needed.

The so-called touch screen is a simple IR emitter / receiver matrix over the green screen CRT, placing your finger on a 'button' would break two beams indicating your finger location. Primitive but i am sure it works!

On the front panel we have menu buttons VTR, FX, MIX, SEQ, SET UP & U. Visibly the 'FX' button has been used the most. Below that we have Take; Go & Stop then a Spinwheel which is a nicely damped 360 degree rotational encoder. Finally on this side we have 8 function keys relating to menus shown on the CRT.

On the other side we have three adjustment knobs, the floppy disk drive, two transition faders and a joystick. The faders and the joystick are of very high quality, damped but smooth and light to touch with most of the parts made from machined aluminium or steel. The joystick self centres and is 3 axis, X & Y being up, down, left and right with the 3rd axis is provided by the rotation of the black handle which rotates about 20 degrees in either direction and self centres.

Note the 'Maurice II' underneath the monitor, could be a brand for the system, internal CEL Codename for the project and possibly a reference to Maurice Leblanc?

On the back we have an impressive six serial ports, video output (presumably mirroring the internal CRT) and connection for a 2nd floppy disk drive.

A full teardown video is available on my YouTube channel: