Author Topic: CPC6128 Parados and Internal 3.5" floppy drive mod  (Read 13599 times)

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Offline Eidis

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  Hi Guys !

 Some time ago I acquired a lovely CPC6128 which am very fond of. Unfortunately right from the start I noticed some things which needed improvements. The main goals were:

1) Make an RGB SCART cable
2) Power everything with +5V DC
3) Replace AmsDOS with Parados v1.1
4) Install an internal floppy drive

I made the cable using Alternative RGB Wiring pionouts, minus audio out connector and the 100uf capacitor, which can be found here:
TV SCART cable - CPCWiki - The Ultimate Amstrad CPC Community & Encyclopedia!
TV SCART cable - CPCWiki - The Ultimate Amstrad CPC Community & Encyclopedia!

After connecting the SCART cable and a temporary PC PSU to CPC6128 converter I fired it up for the first time and behold, it was working.



Chapter 1: AMSDOS vs Parados

 After little bit of Googling I decided to replace AMSDOS with Parados. I wanted to remove the original chip without destroying it so this made my task more difficult. For it I used the following things:

1) 8W 12V micro soldering iron
2) Solder wick
3) Multicore solder resin







 First of all I tinned all pins of AMSDOS rom so the new solder will bind with the old one and will be better absorbed by solder wick





Then I used solder wick and tried to absorb as much solder as I could from every pin. A low power soldering iron was intentionally used here to avoid damaging the traces and the chip. It is advisable to allow soldering iron and solder wick to make contact only with solder which needs to be removed and avoid touching the PCB. The solder tip should not be held to a pin for more than four seconds. Luckily this soldering iron is underpowered so it is unlikely to cause any damage if held slightly longer, but the previously mentioned rules still apply. I tried to make a contact only for as long as I saw solder being absorbed by the solder wick. Usually it was 4 - 6 seconds.



Here's how it looked after one pass



And here's after second pass. Please note that the main goal is to see clearly through the hole. You can gently probe the pins and watch if they move freely or are still held in place with some solder. This task is very time consuming and requires precision. Please take your time and do not rush things.



After approximately 40 passes the chip finally allowed to remove itself. I soldered a DIP28 socket in its place, used tooth brush and rubbing alcohol to clean off flux from soldered pins and motherboard, and burned a fresh copy of Parados in Winbond W27C512 EEPROM which is cheap and readily available. For this task I used Sivava Willem programmer. Before burning the data, I needed to set offset to 8000 in the programmers software, otherwise Amstrad failed to recognize the chip.



Here's how the PCB looks with the newly installed DIP28 socket from below.



Chapter 2: Fitting 3.5" floppy drive and preparing the cables

 First of all I would like to say sorry to every Amstrad purist for the butchery which will be revealed in the following pictures.

 Amstrad did a very good job at stopping people from fitting ordinary 3.5" drives in their hardware. The mounting points and dimensions for both of them are completely different. In order to fit a 3.5" drive I needed to cut out the plastic which was used to mount the original drive.

Here is the upper part before the butchery



After



Now the lower part before the butchery



And after



I used a fragment of one floppy drive to mark the mounting points where I will need to drill holes. If anyone is interested, I can post the exact measurements.



For this task I used BOSCH drill and a tip with 3mm diameter. The drill was operated at the maximum lowest speed. Here are the results.





With floppy drive mounted in place. I used regular PC screws and five carton washers for each screw (see example on the floppy drive). The total washer height needs to be 3mm.



Viewed from the side



Here's how it looks when half assembled. I chose Mitsumi D353M3D floppy drive because it has smaller form factor, compared to others, has good placement for data and power sockets, the green access led stays off when the drive is not being accessed (not the case with many other floppy drives where it lights up dimly when the drive is not used and normally when accessed) and consumes less power than others.



As you can see, it is very easy to modify the internal floppy cable from 26 pin to 34 pin. It is almost transparent and can be transplanted to a donor IDC34 connector without crimping. Please note that side pins of the power connector need to be swapped, because Amstrad decided to put +12V on the +5V pin and vice versa.



Here is a front view of the newly installed floppy drive, perfectly aligned with the bottom part of the case.



And a view from the bottom





This is still a work in progress and I will need to find a way to make the upper part of the case fit as nicely as the lower part and find some way to neatly close the gap.



Here is another thing which surprised me. Most modern 3.5" floppy drives entirely run on +5V. The original 3" requires +5 and +12 because the step motor is rated for +12V. This was a very positive surprise because now I can power the whole system with +5V 3A PSU. But until then I will use the temporary replacement.



In order to fake the ready signal for the floppy drive, I soldered pins 33 and 34 on the motherboard together. Here is Le Batman Forever demo, running on my lovely Amstrad.



Please let me know your thoughts and suggestions about this mod.

P.S. A black floppy drive and +5V 3A PSU are on their way ;)

Keep the scene alive !
Eidis
« Last Edit: 19:01, 17 March 12 by Eidis »
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Offline Bryce

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #1 on: 21:00, 17 March 12 »
All fine work my friend. The "offset" you mention is because you used a 64K EEPROM and some Address bits are being held high. With the extra space in the EEPROM, you could install AMSDOS too and add a switch to select which one you want. More info on that here:
DualOS - CPCWiki - The Ultimate Amstrad CPC Community & Encyclopedia!
DualOS - CPCWiki - The Ultimate Amstrad CPC Community & Encyclopedia!

Bryce.

Offline OCT

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CPC 664 internal 3.5" floppy drive mod
« Reply #2 on: 21:36, 17 March 12 »
First of all I would like to say sorry to every Amstrad purist for the butchery which will be revealed in the following pictures.
They've all been through the suffering  :o of seeing this already (from a time before the 664 was considered such a rara avis).

Quote
Amstrad did a very good job at stopping people from fitting ordinary 3.5" drives in their hardware. The mounting points and dimensions for both of them are completely different. In order to fit a 3.5" drive I needed to cut out the plastic which was used to mount the original drive.
[...]
For this task I used BOSCH drill and a tip with 3mm diameter. The drill was operated at the maximum lowest speed. Here are the results.
Alternatively, clockmakers' or opticians' screwdrivers of increasing size, each rotated manually a few times, do the trick as well with minimal danger to the old plastic.

You may try and integrate an HxC with buttons and SD card slot in the spare space (since it does not seem to be available with a case just yet: "3.5 inch USB SSD Floppy Drive Emulator 1.44MB": Could this be a Poor Man's HxC?
"3.5 inch USB SSD Floppy Drive Emulator 1.44MB": Could this be a Poor Man's HxC?), and display through the top cover.
« Last Edit: 01:05, 18 March 12 by OCT »

Offline Bryce

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #3 on: 21:40, 17 March 12 »
Maybe I missed it, but did you mention whether the original ROM survived the 40 rounds of soldering?

Bryce.

Offline Eidis

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #4 on: 23:02, 17 March 12 »
 Thanks Guys for all your suggestions !

 Yes, the AmsDOS rom survived and is in good condition. That micro soldering iron is a real gem and safe guard for works like these





Here are the dumps:

Edit: Oops ! The previous link was broken. Here is a working one.

http://www.MegaShare.com/4026588



However, I have compared it with amsdos.rom which comes with WinAPE and they are identical. I was hoping that I will have an undumped ROM as well ;)

P.S. Is it really worth while to install a dual dos rom with AmsDOS and Parados ? Untill now every software which I have tried runs fine with Parados.

Keep the scene alive !
Eidis
« Last Edit: 08:53, 18 March 12 by Eidis »
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Offline fgbrain

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #5 on: 23:25, 17 March 12 »
Quote
In order to fake the ready signal for the floppy drive, I soldered pins 33 and 34 on the motherboard together.
Did you check whether it's possible to avoid this by a proper jumper/mod on the drive itself? That way you would have the ultimate alternative to the initial 3" drive.

BTW, great pics & thanx for your guide!
_____

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Offline steve

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #6 on: 23:33, 17 March 12 »
@Eidis, excellent job and well documented, is it possible to remove the white front plate from the drive and replace it with a slightly larger plate to cover the gap?

Fitting the HxC in the gap is also a good idea.

Edit: just noticed you have a black drive coming, but maybe you can still fit a new panel to it?
@Gryzor, this mod deserves to go in the Wiki, for those thinking of doing the same thing.
« Last Edit: 23:42, 17 March 12 by steve »

Offline TFM

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #7 on: 00:27, 18 March 12 »
Great job!!!
 

P.S. Is it really worth while to install a dual dos rom with AmsDOS and Parados ? Untill now every software which I have tried runs fine with Parados.

Well in case you like to run CPM or DR. Logo then you do need the Amsdos ROM.
 
Further you can also install advanced DOS like the XD-DOS f.e. in the W27C512 EEPROM, and you still have one 16 KB part free ;-)
 
 
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Offline OCT

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Re: Parados and Internal 3.5" floppy drive mods
« Reply #8 on: 00:41, 18 March 12 »
Quote
Thanks Guys for all your suggestions !

Yes, the AmsDOS rom survived and is in good condition. That micro soldering iron is a real gem and safe guard for works like these
They used to be available from Conrad BTW (though the Stannol Micro-Lötkolben (Lötnadel), 12 V 203430 im Conrad Online Shop I find now does not look exactly similar, nor quite as cheap), but not really long-lived as regards their heating element (several died long before needing a replacement tip).
Quote
Is it really worth while to install a dual dos rom with AmsDOS and Parados ? Untill now every software which I have tried runs fine with Parados.
Yes, but you can nowhere near use the full capacity of DD 3.5" disks with AMSDOS - and would usually need a side (head 0/1) switch in hardware, whereas ParaDOS does crash or at least screw up the screen (by showing its message again) with some loaders that re-initialize ROM 7 later on, and has some code that CP/M apps rely on removed (as documented, to make room for its file manager/menu instead).

BTW, what was broken on the original 3" drive and what has become of it?

Fitting the HxC in the gap is also a good idea.
We've long been hoping&waiting for an HxC that comes in a suitable form factor with front display/buttons, SD card reader, and faceplates (preferably both black and "computer grey") at least with breakpoints to fit 3, 3.5 and 5.25" slots as a full-fledged drive replacement.

Quote
@Gryzor, this mod deserves to go in the Wiki, for those thinking of doing the same thing.
Please feel free to also use material from/links to my earlier Retrofitting a CPC 664 with a 3.5" drive (ParaDOS recommended for full capacity)
Retrofitting a CPC 664 with a 3.5" drive (ParaDOS recommended for full capacity) - will try to find the extra images lost with the external host as well.
The 3.5" drive as shown there actually has one of the READY mods mentioned by fgbrain.
« Last Edit: 01:07, 18 March 12 by OCT »

Offline Eidis

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #9 on: 01:09, 18 March 12 »
 Thank you Guys for the warm welcome !

 I am puzzled. Could anyone please explain why do I need a drive with Ready signal instead of jumpering pins 33 and 34 ? According to the following Wiki articles, the only inconveniences which I could experience would be a motor which spins all the time or some games, which have data on both sides of the 3" floppy disk, not working.

 When I turn on the CPC6128 the chosen Mitsumi drive sits there quietly and when I run the "cat" command, after listing the directory contents it stops spinning the disk after approximately two seconds just like when in normal use. Other floppy drives, which I have tested, showed strange symptoms like dim light of access led when the drive is not being accessed. That was the main reason why I decided to go with Mitsumi D353M3D.

Disk drives - CPCWiki - The Ultimate Amstrad CPC Community & Encyclopedia!
Disk drives - CPCWiki - The Ultimate Amstrad CPC Community & Encyclopedia!

Drive Compatibility - CPCWiki - The Ultimate Amstrad CPC Community &
Drive Compatibility - CPCWiki - The Ultimate Amstrad CPC Community &

@steve, thank you for the praise. The upper part of the case still needs to be filed to become a perfect fit. I like inserting physical media in these oldskool computers, the loading speed is very good and over the years I have accumulated a giant pile of 3.5" floppies so there is no need for HxC. I want to keep the original floppy drive bezel so IMHO the gap could be filled with rubber object, shaped for the gap, or a small piece of custom shaped wood, which has black vinyl tape wrapped around it.

@TFM/FS, are there some other advantages as having HDD and CPM support when using XD-DOS ? Does it read floppies faster or has some sort of data cache ?

@OCT, This soldering iron has survived five tips and has seen the guts of many exotic hardware ;) The original 3" drive looks like new and I took extra care to preserve its integrity. It probably works fine or needs a belt replaced. I have no media or way to test it but it would be good if it found a caring and loving new home. Otherwise it will just collect dust.















P.S. I'll do a proper Wiki article for this project as soon as it will be finished. Still waiting for the black floppy drive from UK and China quality PSU

Keep the scene alive !
Eidis
« Last Edit: 02:05, 18 March 12 by Eidis »
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Offline TFM

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #10 on: 02:00, 18 March 12 »
@TFM, are there some other advantages as having HDD and CPM support when using XD-DOS ? Does it read floppies faster or has some sort of data cache ?

Well, the XDDOS provides support for the Vortex format which is (at least) in some Countrys standard. If you start from scratch it doesn't matter. In addition XDDOS provides a bunch of interesting new commands (copy, format....). Just type !HELP to show the ROMs. And then !HELP,rom-number-of-XDDOS to show its RSX commands.
 
EDIT: You can also use DOS like RODOS, which provides subdirectories with names and so on.
« Last Edit: 19:25, 18 March 12 by TFM/FS »
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Offline fgbrain

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #11 on: 09:33, 18 March 12 »
Quote
I am puzzled. Could anyone please explain why do I need a drive with Ready signal instead of jumpering pins 33 and 34 ? According to the following Wiki articles, the only inconveniences which I could experience would be a motor which spins all the time or some games, which have data on both sides of the 3" floppy disk, not working.

Ready is required to tell OS that disc is present in the drive. By 'jumpering pins 33 and 34' you just tell the OS that disc is always inserted. For serious usage you really need Ready signal.
_____

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Offline OCT

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #12 on: 10:33, 18 March 12 »
The original 3" drive looks like new and I took extra care to preserve its integrity. It probably works fine or needs a belt replaced. I have no media or way to test it but it would be good if it found a caring and loving new home. Otherwise it will just collect dust.
...which would be a pity, since I still do have spare belts but a drive with defective circuitry (that any expert is welcome to have a look at - with a bit of luck, not more than an SMD driver transistor damaged by a voltage spike) - and thought of trying to make a working one out of that if one defective in other parts came along, but a 3" that just needs belt replacement like yours at the most would be best of course. :)

As you wrote you don't need it anymore, just send a message how much this would cost with postage to Germany.

While you're at modifying your CPC (especially when considering adding an HxC floppy emulator), other useful switches to add are an ABBA (drive order, for applications that require being run from |A) and a RAM bank exchanger (to easily make memory dumps), as well as an auto-boot toggle (doing |CPM at power-on, which can also load anything else e.g. a menu you put on the boot track).

Offline Eidis

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #13 on: 19:16, 18 March 12 »
@OCT, PM sent.

The internal floppy drive is already recognized as |A drive. Thank you for bringing up the idea of installing a boot menu on the boot track. I'll look into it.

Keep the scene alive !
Eidis
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Offline Gryzor

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #14 on: 20:24, 18 March 12 »
Man, what a fantastic first post... not only was the guide superb, but it was very enjoyable to read, too!


Since you said you'll be doing an article I'll keep off for the time being. But please, if you need any help with it do let me know!


Oh, and welcome :)

Offline OCT

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #15 on: 20:53, 18 March 12 »
The internal floppy drive is already recognized as |A drive.
Yes, so then the HxC won't be (has to become B: if connected simultaneously), if you do add one. Hence the ABBA idea (and by that I don't mean singing Scandinavians in leggings ;) ).

Offline Gryzor

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #16 on: 21:16, 18 March 12 »
Btw, you did an excellent job retrofitting that 3.5" drive, so why not also paint it to match the whole setup?


Oh, also, you can actually build an HxC cable with the ABBA switch integrated to it...

Offline Eidis

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #17 on: 23:58, 18 March 12 »
 Thank you Gryzor !

 You have a very awesome site and friendly forum and it is because of you Guys that I decided to get me an Amstrad in the first place ;) Keep up the good work !

I ordered exactly the same floppy drive on eBay, only with black bezel and a +5V 3A PSU. They should arrive in about 12 days time and I'll post updates on this project as they happen.

Eidis
« Last Edit: 00:26, 19 March 12 by Eidis »
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Offline Gryzor

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #18 on: 15:34, 19 March 12 »
Awww I feel all warm and fuzzy inside now :)


Really cool that the same drive comes in black (remember the time when everything came in just white? It was such a revelation when I got my first black CD writer to match my PC tower...), do show us some pics :)

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #19 on: 23:33, 19 March 12 »
Great post with lots of good pictures...I like pictures  :D
Keep us updated, it's really nice to see.
 
 
Cheers,
Shane
The CPC in Australia...
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Offline OCT

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #20 on: 02:12, 07 January 16 »
I chose Mitsumi D353M3D floppy drive because it has smaller form factor, compared to others, has good placement for data and power sockets, the green access led stays off when the drive is not being accessed (not the case with many other floppy drives where it lights up dimly when the drive is not used and normally when accessed) and consumes less power than others.
Happened to get my hands on a classic-CPC-colored one of exactly these too, and learn it could be modded to READY fairly easily from the (tiny) right-hand side of DEN3:
http://www.pitsch.de/stuff/amiga/a1korg_01.pdf
Have you done that mod per chance and can report whether it went well indeed?

Offline TFM

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Re: CPC6128 Parados and Internal 3.5" floppy drive mod
« Reply #21 on: 19:48, 07 January 16 »
Great find! Thanks!
TFM of FutureSoft
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