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General Category => NC100, NC200, PCW, PDA600 - the rest of the Family! => Topic started by: Starglider on 09:20, 17 October 16

Title: Light pen screen alignment is out
Post by: Starglider on 09:20, 17 October 16
Hi, I have the Electric Studio light pen for PCW. It works, but the alignment is off. No matter where on the screen I place the pen, the crosshair cursor is confined to the right fifth of the screen. It moves parallel to my pen movement, but is not under the pen tip.

Any ideas?
Title: Re: Light pen screen alignment is out
Post by: Bryce on 10:00, 17 October 16
I can't be sure on the PCWversion, but the CPC version certainly had a calibration setting in the menu that needed to be adjusted every time you used it.

Bryce.
Title: Re: Light pen screen alignment is out
Post by: Starglider on 20:52, 17 October 16
Yes I see that in the CPC Light Pen MkII manual, but nothing in my MkI PCW manual.  >:(

I would've thought the MkI would need calibration if MkII did!


Edit: In the CPC MkII manual it says calibration will auto-run on first load. I wonder if that happened on the PCW version and now I'm stuck with the previous owner's calibration. I don't see any obvious file on the disk, but maybe it's a hidden file. How do I view hidden files?
Title: Re: Light pen screen alignment is out
Post by: FloppySoftware on 02:06, 20 October 16
Try with
Code: [Select]
DIRS in CP/M. Good luck!
Title: Re: Light pen screen alignment is out
Post by: Starglider on 02:16, 20 October 16
Hmm, that just says:


NON-SYSTEM FILE(S) EXIST
Title: Re: Light pen screen alignment is out
Post by: FloppySoftware on 08:52, 20 October 16
In that case, there are not hidden files (in that user area).
Title: Re: Light pen screen alignment is out
Post by: Starglider on 09:27, 20 October 16
Interesting. OK.

I hope someone might have some more ideas on this.

Sent from my SM-G935F using Tapatalk

Title: Re: Light pen screen alignment is out
Post by: Starglider on 03:58, 28 October 16
Any other ideas welcomed!
Title: Re: Light pen screen alignment is out
Post by: Starglider on 18:50, 26 November 16
Hopeful bump

Thanks!!

Title: Re: Light pen screen alignment is out
Post by: Starglider on 00:05, 13 May 18
"Oh God please" bump!
Title: Re: Light pen screen alignment is out
Post by: GeoffB17 on 02:50, 13 May 18
If you're looking for a 'hidden' file, one way would be to use the disk within LocoScript, which will list files in various user areas.   This may show up 'normal' files which might not be normally visible within CP/M.

There is also a DIR variant called DISK which I believe lists files in ALL user areas, also another prog which has variants, at least one of which is called LDIR, which also lists files in all user areas.

Then, the disk sector editor DU-V86 will allow display of the directory tracks, this may reveal any oddities lurking there.

Another option might be to create a .DSK image of the disk, that image file can then be inspected manually using DUMP or similar.   If you made such an image, and attached it, I'd gladly inspect it for you.

Geoff
Title: Re: Light pen screen alignment is out
Post by: Starglider on 03:25, 13 May 18
If you're looking for a 'hidden' file, one way would be to use the disk within LocoScript, which will list files in various user areas.   This may show up 'normal' files which might not be normally visible within CP/M.

There is also a DIR variant called DISK which I believe lists files in ALL user areas, also another prog which has variants, at least one of which is called LDIR, which also lists files in all user areas.

Then, the disk sector editor DU-V86 will allow display of the directory tracks, this may reveal any oddities lurking there.

Another option might be to create a .DSK image of the disk, that image file can then be inspected manually using DUMP or similar.   If you made such an image, and attached it, I'd gladly inspect it for you.

Geoff
Thanks. I actually don't think there is a hidden light pen alignment file, otherwise it wouldn't be hidden. That was just one theory above.

My query is more about how the electric studio light pen actually works. Basically wherever I hold it, the cursor moves vertically correctly, but horizontally is stuck in a column on the rightmost inch of the screen. It's as if the width of the screen is one inch, according to the pen. Every movement gets compacted into the right side only.

This doesn't lead to very appealing art

Thanks!, Starglider aka ԹҽɾíƒɾɑϲԵíϲ's RҽԵɾ๏ RҽϲíԹҽs
️ http://youtube.com/perifractic
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Title: Re: Light pen screen alignment is out
Post by: GeoffB17 on 19:46, 13 May 18
OK, might not be a 'hidden' file.   Maybe a file that's been deleted, but is still there.   Could be checked, and recovered?

I should have asked before.   Did the light pen ever work?   Is the software on an original labelled disk.   Are the menu options visible if you look in the .COM file, and does that show a config option that you normally don't see?   May need to try to work out why your prog believes it's fully installed/configured when in fact it is not?   What happens if you copy the .COM file alone to a new disk and try to run that?

Geoff
Title: Re: Light pen screen alignment is out
Post by: JohnElliott on 01:36, 14 May 18
My query is more about how the electric studio light pen actually works.

You rang?

The Electric Studio light pen is covered in my 'PCW Hardware' document, distributed with JOYCE or available here (http://www.seasip.info/Unix/Joyce/hardware.pdf). Section 11.4 covers the light pen, but in brief: the light pen has a 12-bit counter which starts to decrement when its light sensor is triggered, and stops when there is a horizontal retrace.
Title: Re: Light pen screen alignment is out
Post by: Starglider on 02:20, 14 May 18
You rang?

The Electric Studio light pen is covered in my 'PCW Hardware' document, distributed with JOYCE or available here (http://www.seasip.info/Unix/Joyce/hardware.pdf). Section 11.4 covers the light pen, but in brief: the light pen has a 12-bit counter which starts to decrement when its light sensor is triggered, and stops when there is a horizontal retrace.


I did ring!  ;D  Thanks for coming to the door!


I made a little video of the fault, if you could take a look and let me know any ideas? I'll be trying to fix it in an upcoming episode of Retro Recipes. Many thanks!:


https://www.youtube.com/watch?v=mq3Qtfc7Ab0
Title: Re: Light pen screen alignment is out
Post by: P5ychoFox on 21:25, 14 May 18
Looking forward to a PCW related retro Recipes episode. I used to have a PCW light pen and it always worked fine (no help to you I know). Such old technology but still captivating to me. I hope you get it working, keep up the great work on your channel.
Title: Re: Light pen screen alignment is out
Post by: Starglider on 21:41, 14 May 18
Looking forward to a PCW related retro Recipes episode. I used to have a PCW light pen and it always worked fine (no help to you I know). Such old technology but still captivating to me. I hope you get it working, keep up the great work on your channel.
Thank you, that means a lot! I will do. Down the line I also want to make a "Refurbish This!" Episode for the PCW. Case repair, retrobrite, space bar repair, and such like. I was lucky to find one in the USA and already upgraded it with a second High Density drive.

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

Title: Re: Light pen screen alignment is out
Post by: 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?
Title: Re: Light pen screen alignment is out
Post by: Starglider on 23:24, 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?
Hmm would that bit error be with the legitimate software, the light sensor, the serial port, or somewhere else normally?

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

Title: Re: Light pen screen alignment is out
Post by: Starglider on 23:34, 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?
P.S. Could I write that in BASIC? I have Mallard but no manual or PDF.

Thanks!, Starglider aka ԹҽɾíƒɾɑϲԵíϲ's RҽԵɾ๏ RҽϲíԹҽs
️ http://youtube.com/perifractic
️ http://patreon.com/perifractic
Title: Re: Light pen screen alignment is out
Post by: JohnElliott on 01:02, 15 May 18
My guess would be that the problem is in the hardware of the light pen interface.

I think any diagnostic program would need machine code to get an adequate response time.
Title: Re: Light pen screen alignment is out
Post by: Starglider on 01:40, 15 May 18
My guess would be that the problem is in the hardware of the light pen interface.

I think any diagnostic program would need machine code to get an adequate response time.
Thank you. I'm wondering if an aging resistor might be a cause in the serial box.

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

Title: Re: Light pen screen alignment is out
Post by: Starglider on 04:59, 15 May 18
OK John, I've opened things up. Photos: https://photos.app.goo.gl/VRwa1uQGMpDOiUWo1 (you can zoom in far)


I think the chip at the top right is the counter. Motorola MC74HC4040.


Where would you start? Replace that chip? Replace the resistors first? Anywhere else?


The other chips are gates, trigger inverters, bus buffers.


(Also in the photos is the USA PCW adapter I have to use for the serial port. It's just a passthrough ribbon cable inside. Any chance this could be the cause of my woes?)
Title: Re: Light pen screen alignment is out
Post by: JohnElliott on 12:40, 16 May 18
That level of diagnosis is way out of my league. I certainly wouldn't go replacing components without first having written the diagnostic program to check my guess about what the interface is doing.
Title: Re: Light pen screen alignment is out
Post by: Chinnery on 15:07, 16 May 18
Looking at the board, all the ICs seem to be 74xxx logic chips, which are reasonably common.
I know you've been known to take a hammer to a problem to fix it (literally)... perhaps you could use a proverbial hammer and change these ICs one by one? At least you'll know if it was hardware or software :)
Slightly more sensibly, I know my el-cheapo eprom programmer can check these logic ICs, so perhaps a less aggressive approach would be to take each chip out and test it in a similar programmer? Mine is a TL866CS which is freely available on ebay... and not let me down yet in retro rom programming. I haven't yet used it to test a logic chip yet though.
Title: Re: Light pen screen alignment is out
Post by: Starglider on 20:08, 16 May 18
Thanks guys!

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

Title: Re: Light pen screen alignment is out
Post by: Starglider 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 (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.)
Title: Re: Light pen screen alignment is out
Post by: Starglider 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

Title: Re: Light pen screen alignment is out
Post by: ComSoft6128 on 20:31, 12 September 18
Good video, watched it this afternoon, thanks!
Title: Re: Light pen screen alignment is out
Post by: Starglider on 20:38, 12 September 18
Thanking you kindly!