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1
Technical Support / Re: CPC 464 - very quiet speaker audio
« Last post by Audronic on Today at 02:28 »
@gw0udm


It is also possible that the Speaker Cone is Jammed and only moves a small amount ?
If you have an other speaker that you could use as a test that might prove if I am correct.
Or keep changing the Caps C301 is also a good one to change

Good luck
Keep Safe

Ray
2
Technical Support / Re: CPC 464 - very quiet speaker audio
« Last post by gw0udm on Today at 00:20 »
Right a quick update


Rummaging through the junk box I've found a couple of spare capacitors and changed them out (C309 and C311) but with no improvement (see pics, although I'd only done one when I took this).


I think the one that thomas mentiones in the post above is C308 (also circled on the pics). It's covered with what looks like a blob of glue. Unfortunately I don't have any of these in stock (look like a 22uF) so will get one in.


There is also C314 which is a non-polarised electrolytic, don't have any of those either so maybe worth replacing that too.


Any other thoughts? I will probably try and get hold of one of these cheap oscilloscopes and see if I can trace the path if I can't get anywhere.


James
3
Programming / Re: Using Index registers
« Last post by roudoudou on Today at 00:13 »
use them when you want, this is not school, neither an exam. Optimisations may come later if needed...
4
Programming / Using Index registers
« Last post by IndyUK on Yesterday at 23:43 »
Hi folks,

Wanted to get peoples opinion on the use of the Index registers. Whenever I read any tutorial on Z80 assembly, I always find that somewhere in the index register section there is always a suggestion of not using them because they are slow. It is true to say they are slow (based on the t-states tests I've done) but, I think they are very convient. I have been experimenting with creating array types of objects (probably their primary use) and really tried to void using them but, just couldn't avoid them altogether. My code got messy and lengthy and to be honest I lost interest in continuing with the project.

So my question really is - when should we use them and when not?

Looking forward to your feedback.
5
Hi

Wanted to join the others to also say "nice job".

It's strange to not be able to scroll above or below what you have written.

Discovered something that maybe of interest to you. If you ever need to examine your BASIC program. Open the Assembler screen (F3) and under the File menu there is a "Read BASIC" option. That will dump your listing into the assembler window. I don't think you can edit and run it from there but, at least you can examine the code and then make the changes in the emulator screen. It's not perfect but I did find it kind of useful while bug/error fixing.

Good luck with future projects.
6
Hi all,


This is my first post, apologies if anyone has asked this question before.


I found a PCW 8512 in the box with the printer, keyboard and everything at a car boot sale recently for £40, which I thought was a pretty good deal. Unfortunately the machine doesn't work. When powered on, the CRT does not light up at all, both disk drive LED's are on constantly and the disk drive motors seem to run continuously. The keboard Shift Lock light does go on and off as normal when the button is pressed. The upper disk drive LED also seems to "pulse" on a regular basis. I took a video, see below:


https://photos.app.goo.gl/yHDyLXRfrZRLxLs39


Any ideas? Seems fairly profoundly dead but I guess could be a capacitors/power supply problem? I took it apart, cleaned the vast amount of dust from the inside, pressed down on the socketed chips on the CPU board (CPU itself and RAM) and checked that the internal fuse wasn't blown. It seemed fine although the filament inside is at quite an angle. (but did not seem broken)


Thanks in advance,
gelthor



7
Well, if you want, give me the dsk image of exolon to replace the one used then  :)
Now, about CPC 464 compatibility, since all games in "direct file form" are extracted from dsk images, it means that they run 100% only on "Amsdos equipped" CPC with basic 1.1
Differences in memory usage (464 had a few more ram available because of the lack of amsdos, also many system variables use different places in ram) ,and different basic versions (for example, some games use loaders with basic commands that are not supported by previous basic 1.0 of CPC 464) prevent some games from loading on a CPC 464.
Also, some games require 128kb ram, so obviously these can't run on 464 models too.
In order to load these "direct file" games on 464 machines, you can either try to use the dsk image and FDC emulation, or use a snapshot file of the game, if available.

btw, added 2 more games to the list:
-MUTANT MONTY
-BMX SIMULATOR
9
Applications / Re: UniDOS, the new multi-device AMSDOS replacement
« Last post by OffseT on Yesterday at 12:18 »
A preliminary version of the Nova DOS node is now available at https://unidos.cpcscene.net.


More info about Nova expansion card:
https://pulkomandy.github.io/shinra.github.io/nova.html


This is a very first version so that X-Mass users can immediatly take advantage of this card because NV-RAM support from FAT32 is a bit slow.
Of course, Albireo users can use it too. They won't notice as much speed boost, but it will safe write accesses to their MicroSD card (it will also consequently make the MicroSD card presence optionnal).
Also, Nova let you use UniDOS without any other additionnal hardware (just limited to floppies and tape).


Final version of Nova will provide a public API so that other programs/ROMs can also use it in a system-friendly manner.
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Amstrad CPC hardware / Re: LambdaSpeak FS
« Last post by RetroCPC on Yesterday at 12:07 »
Really impressive - as soona s ai complete the current PCB I'm working on I plan to contact Dream and see whats possible - I'd like to use there later SAM5xxx series IC's as we can then easily make a CPC "Sound card" that outperforms the Roland box :)
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