Light pen screen alignment is out

Started by Starglider, 09:20, 17 October 16

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Starglider

Thanks guys!

Thanks!, Starglider aka ԹҽɾíƒɾɑϲԵíϲ's RҽԵɾ๏ RҽϲíԹҽs
[emoji973]️ http://youtube.com/perifractic
[emoji973]️ http://patreon.com/perifractic

Starglider aka Perifractic
http://youtube.com/perifractic 

Amstrad PCW8256 with Gotek & HD Drive B

Starglider

#26
Quote from: JohnElliott on 23:00, 14 May 18
I'd probably try to diagnose this by writing a program that mimics the normal lightpen read function and records what values were read from the lightpen as it does so.

Thinking about this: If the counter starts ticking when the pen sees the electron beam, and stops ticking when the beam hits the right margin, then if the cursor's always on the right that means the PCW is only seeing small changes in the counter. That suggests the counter's only decreasing by small amounts. Maybe one of the bits isn't rolling over?

Edit: Ignore the below. I swapped the Inverter/Trigger next and it worked! That means that was the faulty chip. I've ordered a new one and will have 2 working light pens :) I'll post the video next week at http://youtube.com/perifractic. Thanks all!

Previous text:


Hi all, I finally sourced a second, working unit and have started chip swapping. Here's a layout of what each of the 7 chips does:

[GATE] [GATE] [COUNTER]
[INVERTER/TRIGGER] [BUS BUFFER]
[GATE] [BUS BUFFER]

I've already swapped the top-left Gate and the Counter, but the problem remains.

What would you swap next for the issue shown in my video? (I ask as it's so time consuming to do.)
Starglider aka Perifractic
http://youtube.com/perifractic 

Amstrad PCW8256 with Gotek & HD Drive B

Starglider

Here's the full fix video! Thanks for all your help!


https://youtu.be/EBfkiprmoi0

Thanks!, Starglider aka ԹҽɾíƒɾɑϲԵíϲ's RҽԵɾ๏ RҽϲíԹҽs
[emoji973]️ http://youtube.com/perifractic
[emoji973]️ http://patreon.com/perifractic

Starglider aka Perifractic
http://youtube.com/perifractic 

Amstrad PCW8256 with Gotek & HD Drive B

ComSoft6128

Good video, watched it this afternoon, thanks!

Starglider

Starglider aka Perifractic
http://youtube.com/perifractic 

Amstrad PCW8256 with Gotek & HD Drive B

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