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CPC Laptop.

Started by Bryce, 12:20, 25 October 14

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Bryce

Hi all,
     I decided to start my "Winter project" and as discussed in an earlier thread, I thought I'd take a go at making a decent CPC Laptop. So here's the plan...

The Laptop I've chosen is a Compaq LTE Lite/25E:

[attach=2][attach=3][attach=4]

Craigsbar kindly sorted out two 6128+ PCBs, both of which are supposedly fried, but I'm hoping to get at least one of them back to life. If I get one working, here's plan-of-attack:

1 - Get one of the plus PCBs working.
2 - Swap LCD and build a controller interface (it currently has a mono 10in which I need to swap to colour).
3 - Find some way of using the laptop keyboard with a CPC.
4 - Build an 18V to 5V / 12V switch-mode PSU so that I can use the original Laptop PSU.
5 - Beat the PCB and new bits into the laptop case.
6 - Build an interface to allow that cool trackball in the lid to work as an AMX mouse.
7 - Add the expansions: X-mem and HxC - Possibly a CPC booster with bluetooth module too.

Other than that my goals are: All original CPC ports available at the back. No external parts. Laptop must be closeable as designed.
Use original power button, use the original LED points for the HxC, power and AMX LEDs, ie: it should look like original on the outside, except for an Amstrad badge :). I've dropped the idea of using the laptop batteries because the originals are both dead. I also don't think I can get the floppy to fit inside, so the HxC will replace it. I will hardwire a cartridge inside with AmsDOS/ParaDOS.

This will be a looooong project, but I'll document it here as I progress.

Bryce.

Dr Tiger Ninestein

Nice one Bryce, can't wait to see the finished product.

Bryce

Just started the investigation... Unfortunately the previous owner or person who attempted to repair it didn't own a Torx screwdriver, so it took a while to get the damaged screws out, but here's what's inside:

[attach=2]

At the top you can see the computer module, below from left to right is the battery (12V 2.2AHr - now 0AHr), in the middle is a dinky Seagate ST9144A (120MB 44pin IDE, haven't checked whether there's anything on it yet) and on the right a Citizen VIDA-15B (26pin, but with ready signal and seems to work fine). Just incase there's any Compaq fans out there, cursing my children because I'm destroying a perfectly good laptop, I'm not - It's fried. The LCD inverter is dead, the flat cable to the lid is torn and the power PCB is fried. Here's the space I have inside. It's 270mm wide, 200mm deep and 25mm height, so a plus PCB will fit inside if I remove the cartridge riser and cut off the "finger" with the external floppy connector. There's some internal walls that I'll have to remove and I might need to add some other support then for the keyboard. Luckily the keyboard mounting point are on the case and not on the PCB like newer laptops.

[attach=3]

[attach=5]

10in my arse! The viewable screen area is 8.4in diagnal. The lid is 20mm deep though, so any modern LCD will fit inside. On the right you can see the inverter which will be scraped and below it is the trackball - Seperate PCB: Win! Alps controller, probably RS232 or PS/2: Second win!

[attach=4]

The keyboard is rather flat with a membrane that obviously won't match the CPC matrix, so I'm thinking of making a PCB with microswitches to lay under it, hopefully there's enough space for that.

Bryce.

Bryce

Just in case anyones interested, here's the actual PC that was inside that module:

[attach=2][attach=3]

That black box is a 7.2V battery, there's also a CR2430 for the RTC and BIOS. There's three PCBs sandwiched on top of each other. On the second picture you can see the socket for a co-pro which wasn't fitted. Right underneath it is the 386SL with zero cooling :D What were they thinking! (Starting to sound like Dave in one of his EEVBlog teardowns, must resist using words like Fair-dinkum, Hum-dinger and Bobby-dazzler :D - Greetings Dave). You can see the regulator under that plastic strip too. It's made to be easily replaceable through a door on the side, so they obviously weren't convinced about its reliability, and rightly so, this one is fried too.

But enough waffling about 386s, time to check out the two 6128+ PCBs that arrived this morning :)

Bryce.

Bryce

Quick update: After the disappointment of the first donor PCB having a dodgy ASIC, I took a look at the second one and hoped it wouldn't be the same. It had some strange mod which involved several cut tracks, jumper wires to the back of the floppy port and a chip (74LS32) piggy-backed onto IC7 (74HC14 which also had a pin cut). Not sure what this mod did, but because of all the messing about on the PCB and the fact that the CPU, AY and NR02 had all been removed from the board, I though this would be in a worse state than the first one. However, it booted to a blue border with yellow window - A classic sign of dead RAM in the lower 64K. One quick swap later and re-installing an AY and CPU (I also replaced the cut 74HC14 just for good measure) and we have a fully working plus PCB!! Yaaaa the laptop mod can continue! The floppy hardware works, but it seems the upper 64K is dead too, so I need to swap that later when I have time.

Next step after that is to remove the right section of the PCB (the bit with the floppy port and filter with red wires). Without removing that it wouldn't fit in the case. Luckily this can be removed as it only contains the wires to the port (no longer needed) and a single power track which I can bridge.

Bryce.


EgoTrip

Can I have it when its done?

Bryce

Ehhh, no :)

My main reason for building it is because I want to be able to write software for  hardware expansions when I'm away from home. I could write it on an emulator of course, but I can only test it with the expansion connected, which isn't possible with an emulator.

Bryce.

CraigsBar

#7
Yay, at least a 50%success rate. The piggyback on the disc circuitry is the sts copymod, as used by xexor to slam the brakes on the drive motor to make the 8k sector discs copyable and it works a treat.

I have one in my main 6128plus as well.
IRC:  #Retro4All on Freenode

EgoTrip

Worth an ask  :D


If its a success, how much would it set someone back for you to build another for them? I doubt I'll ever have the money spare (CPC is pretty low down the list tbh, especially with decent emulation available) but its worth finding out in case someone I know wins the lottery and is generous towards me with their winnings.

TFM

Compliments Bryce! This looks very doable. My biggest concern is actually to get the RGB from the 6128 Plus to the LCD screen. But glad to see that the PCB works.  :)
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

Gryzor

Yessss. Pinning this, a must-watch.

Bryce

@egotrip : Until it's finished I've no idea what it will cost :)

Quote from: TFM on 19:14, 26 October 14
Compliments Bryce! This looks very doable. My biggest concern is actually to get the RGB from the 6128 Plus to the LCD screen. But glad to see that the PCB works.  :)

Actually the LCD (RGB to LVDS) is the least of my worries, I've done stuff like this before. The keyboard is going to be the real headache.

Bryce.

Zoe Robinson

This is such a cool project. Makes me wish I knew what the hell half of what you were talking about meant, so I could do it too. :)

MacDeath

#13
Bryce... please... stop this retro-techno-porn madness...
I'm just coming back from the "µAlchimie 2014" retrocomputer party near my home, with Overflow and Hermol...

And now I see that?

I... I...



(one more thing : I'm gonna pay by check...)

TFM

For the keyboard there are some solutions already, I just don't know if it helps in this case...
Can't find a link, but somebody should know.
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

Bryce

Quote from: TFM on 22:17, 26 October 14
For the keyboard there are some solutions already, I just don't know if it helps in this case...
Can't find a link, but somebody should know.

Really? We're not talking PS/2 or anything here. It's a completely unknown passive matrix with a flat cable.

Bryce.

CraigsBar

Quote from: Bryce on 22:50, 26 October 14
Really? We're not talking PS/2 or anything here. It's a completely unknown passive matrix with a flat cable.

Bryce.
Is anyone running a book on this? Can I have €5 on Bryce solves the keyboard by...... The end of the week?
IRC:  #Retro4All on Freenode

Bryce

Nah, you'd loose your €5 :) I'm looking at the LCD possibilities at the moment. I've found a few 8.4in LCD but they are all 640x480. This doesn't give you enough pixels for mode 2. The 640 on the LCD includes the border, so the actual pixels for the screen would be less than the CPC resolution which could cause a blurred picture. There doesn't seem to be 800x600 in 8.4in, just 8in, so the screen would loose 8mm horizontally and about 12mm vertically. I think I'd prefer slightly smaller but sharper? What do you guys think? 9in seem to be all widescreen versions, I definitely want it to be 4:3 aspect ratio. 10in 4:3 are around, but the cost starts to climb expotentially.

Bryce.

TFM

Well, sleep over it, check out the net (even ebay) and maybe you find such a screen. Maybe it's not produced any longer but somewhere available!?  :)

TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

TotO

#19
8.4" VGA screen (640*480) : G6486H-FF
8.4" SVGA screen (800*600) : G084SN03

The first should allow you to not lose in display size by full removing left/right borders and display fine 256*2xx games.
The second will add a big border... But, allow a nerd touchscreen feature. (sure, the first is the best choice for a laptop)

About the keyboard, yes, building a PCB using the good matrix with micro-switches is fine, because that should allow you to add on its some extra electronics to manage your connectors.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Bryce

Quote from: TotO on 09:01, 27 October 14
8.4" VGA screen (640*480) : G6486H-FF
8.4" SVGA screen (800*600) : G084SN03

The first should allow you to not lose in display size by full removing left/right borders and display fine 256*2xx games.
The second will add a big border... But, allow a nerd touchscreen feature. (sure, the first is the best choice for a laptop)

About the keyboard, yes, building a PCB using the good matrix with micro-switches is fine, because that should allow you to add on its some extra electronics to manage your connectors.

Thanks I'll check out those screens. I'd still prefer to go for 800x600, just because it will give a less blocky picture with no "blended" pixels.
My plan with the keyboard has a few other advantages too. I can assign some of the un-needed keys to things like HxC control and maybe even a digital volume control :) I have some 0.5mm high micro-switches that I think will work, I just need to remove the 40+ tiny screws from the back of the keyboard to find out how much space I have inside. :D

Bryce.

MacDeath

#21
I guess too a 800x600 display would be better for a CPC fullscreen-able display.

384x280... basically it is 400x300 so you can be sure it will fit well, magnify in 2x2 (mode1) and just get a little border.
but of course speccy's 256x192 would look like post-stamp unless you then switch into a 3x3 magnification (not good for Mode2 though).

Of course you would have almost the same border as on real CPC screen (even bigger) and always those lines on the top/bottom, on most softwares, but Batman Demo-able screen is good.
And if you can arrange a manualswitch to be able to go the 3x3 way in case of speccy-ports or spanish games (smaller displays) this could be great.
That's the point : if you can get a nice 800x600 you should try to have different magnification settings and it will be the most accurate option then.

With a 640x480... you can't actually display proper fullscreen unless 1x1 pixels or really stick to native CPC display (640x200)... still can have slightly upgraded vertical (y=240 pixels)

Yeah, CPC was "almost 800x600" before it even existed...


To me, the "full screen" capability of the CPC was perhaps its biggest feature despite not being really a feature to begin with but a by-product of the hardware.

CPC really is the 8bit computer with biggest actual resolution of its generation...

Bryce

The border ratio won't change no matter what mode you use. LCD displays on PCs are pixel-for-pixel, but connecting one to an analogue signal means the picture is resampled and slapped up on the screen exactly as it would look on the monitor. So the border stays the same, but the 640 pixels are then shown across about 580 pixels through a method of averaging. 640x480 might be ok in mode 2, but you have less pixels than the CPC is producing, 800x600 will definitely give you a sharper picture.

Murphys Law seems to effect LCD purchases too by the way. I can buy a 15.6" widescreen panel for €12, but a 800x600 8.4" panel will set me back about €80 and that's without having built the controller - turning out to be an expensive screen.

Bryce.

TotO

The idea with a 640x480 panel is more to be able to keep the 1:1 pixel ratio and remove those big borders that finally made the picture so small on a CTM. (and even smallest on a 8" screen)  :D
Sure, overscan screens will be cut, but... overscan means what it mean.  ;D
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Devilmarkus

Nice idea...
I also think about doing the same with my old Compaq Armada... But as I have no idea, how to connect the LCD display, I forgot the idea ;)

It has a 1024x768 LCD display...
When you put your ear on a hot stove, you can smell how stupid you are ...

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