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Old 8th Mar 2018, 4:53 pm   #27
Keith's Avatar
Join Date: Jan 2003
Location: Tewkesbury, Gloucestershire, UK.
Posts: 517
Default Re: Bush TV22 restoration

Hi again Graham,

I can manage with the progressive scan video for now although the 25Hz refresh rate would be a bit wearing on the eyes long term. Also I think the vsync timing is chopping off the bottom of the frame. I'm not sure that Peter's logic circuit would help in this case. I thought it was designed to correct the inverted line pulses in the frame blanking period and add in the half line pulses but I may be mistaken. I'd be interested to know the repetition rate of your vsync pulses. Good test for your new scope!

I'm still injecting baseband video into the grid of the video amp so I'm a bit sceptical about the corona interference theory - maybe it's a bit more than corona! I need to look in the LOPT can in the dark. Anyway, I've ordered some RS anti-corona spray from (RS are out of stock). In the meantime I'll have a go at adding a bit of decoupling - it's almost non-existant on the TV22.

You're correct about the white bar - I haven't figured how to get a full screen image on the second monitor yet.
Keith Yates - G3XGW
VMARS & BVWS member

Last edited by Keith; 8th Mar 2018 at 4:59 pm.
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