Thread: Ortonview PCB
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Old 3rd Aug 2021, 5:37 pm   #152
SiriusHardware
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Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,485
Default Re: Ortonview PCB

A circuit query regarding the circuit as given in the project document - I notice the NWDS pullup resistor (R3) is 10K - when Tim and I were looking around for ways and means to observe and cure the corruption problem, one thing we did find was that raising the value of the NWDS pullup to 10K made the corruption problem happen more 'reliably', in order to observe it more easily.

If you (Slothie) are still getting occasional flickers in the display cell one step to the left of the data field (so, third one in from the right) even with the four capacitors fitted on A8-A11, try taking that resistor down to 4K7, which is actually the recommended value for the NWDS pullup in the original VDU docs anyway, and the value I had fitted all the time I was playing with my original lash-up version of OrtonView.

220pF capacitors still have not arrived yet, alas. To disable the battery-back feature and just use my 6116 as 'normal' RAM I take it I can either fit a schottky diode (which I happen not to have) in D2 or just link out D2 for now, link pins 2 and 3 of the write protect switch and don't fit the battery or D1. Did I miss anything?

Last edited by SiriusHardware; 3rd Aug 2021 at 5:47 pm.
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