Author Topic: Light pen screen alignment is out  (Read 1814 times)

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Offline Starglider

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Re: Light pen screen alignment is out
« Reply #25 on: 20:08, 16 May 18 »
Thanks guys!

Thanks!, Starglider aka ԹҽɾíƒɾɑϲԵíϲ's RҽԵɾ๏ RҽϲíԹҽs
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Starglider aka Perifractic
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Amstrad PCW8256 | Upgraded EME-232 DD Drive B
(Also Amiga, C64, Apple //e, Atari 400)

Formerly of The Blue Ribbon Soundworks – makers of SuperJAM! and Bars & Pipes for Amiga

Offline Starglider

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Re: Light pen screen alignment is out
« Reply #26 on: 22:49, 27 August 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.)
« Last Edit: 03:21, 28 August 18 by Starglider »
Thanks!
Starglider aka Perifractic
"Recordar es vivir"

Amstrad PCW8256 | Upgraded EME-232 DD Drive B
(Also Amiga, C64, Apple //e, Atari 400)

Formerly of The Blue Ribbon Soundworks – makers of SuperJAM! and Bars & Pipes for Amiga

Offline Starglider

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Re: Light pen screen alignment is out
« Reply #27 on: 10:05, 12 September 18 »
Here's the full fix video! Thanks for all your help!


https://youtu.be/EBfkiprmoi0

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

Thanks!
Starglider aka Perifractic
"Recordar es vivir"

Amstrad PCW8256 | Upgraded EME-232 DD Drive B
(Also Amiga, C64, Apple //e, Atari 400)

Formerly of The Blue Ribbon Soundworks – makers of SuperJAM! and Bars & Pipes for Amiga

Offline ComSoft6128

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Re: Light pen screen alignment is out
« Reply #28 on: 20:31, 12 September 18 »
Good video, watched it this afternoon, thanks!

Offline Starglider

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Re: Light pen screen alignment is out
« Reply #29 on: 20:38, 12 September 18 »
Thanking you kindly!
Thanks!
Starglider aka Perifractic
"Recordar es vivir"

Amstrad PCW8256 | Upgraded EME-232 DD Drive B
(Also Amiga, C64, Apple //e, Atari 400)

Formerly of The Blue Ribbon Soundworks – makers of SuperJAM! and Bars & Pipes for Amiga