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CTV A Brace Of Co-op C2001s

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Jayceebee
(@jayceebee)
Noble V-Ratter Registered
Posts: 1689

@crustytv Thanks for that. I had found the data but not anything modern that was suitable, I might just give it a try. I'm very pleased the way the board turned out, some aspects were a very steep learning curve but filled in quite a few cold winter nights where it wasn't possible to get into the workshop. Apparently there is a Kicad plugin available to make the traces look a little like boards of the period, another project for chassis two this winter maybe.

Next step is chassis number one which has quite a bit of damage due to rust. A selection of convergence pots was a lucky find on eBay and something suitable for the o/c blue A1 control has been offered by Chris The Teleman. Just waiting now for something to restuff the 600uF smoothing can to arrive, also the 4.7 meg resistors in the focus chain which are way out of tolerance. The line linearity coil is broken and winding o/c due to the water ingress but may be repairable. 

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Topic starter Posted : 29/06/2022 10:46 pm
Sundog
(@sundog)
Trusted V-Ratter Registered
Posts: 171

Great job with the restoration!

The geometry is astounding good. Many broadcast monitors used a lot more circuitry and tweaks to achieve that accuracy.

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Posted : 30/06/2022 7:03 pm
Jayceebee
(@jayceebee)
Noble V-Ratter Registered
Posts: 1689

@sundog You would have been less than impressed with the first versions of the A823 chassis. They suffered from bent verticals, some so severe I don’t know how they got past quality control. It was found to be caused by interaction from the line oscillator on the scan drive board and pincushion transductor on the scan control board. These two boards were back to back and the official mod was to rotate the scan drive board 180 degrees.

This solved the issue but the earliest sets had two customer controls for field hold and height. With the board rotated these couldn’t be accessed and we had to blank of the two large holes for the rather large knobs. Thankfully no one complained about the loss of the controls as the design was stable.

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Topic starter Posted : 01/07/2022 10:21 am
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