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#1
the lower voltage on the board is normal.. usually not quite that low..
but if its working..there is no problem!
there is a diag rom you can replace the onboard rom with.. but.. if ya seeing the basic screen.. its working fine!...so the diag isnt going to tell you much...
https://github.com/issalig/amstrad-diagnostics/blob/main/build/AmstradDiagLower.rom is the one you need to replace the onboard rom (you can use the upper rom version if you have a romboard,m4 etc)
but if its working..there is no problem!
there is a diag rom you can replace the onboard rom with.. but.. if ya seeing the basic screen.. its working fine!...so the diag isnt going to tell you much...
https://github.com/issalig/amstrad-diagnostics/blob/main/build/AmstradDiagLower.rom is the one you need to replace the onboard rom (you can use the upper rom version if you have a romboard,m4 etc)
#2
Hi
I am not so familiar with the Amstrad CPC and I am testing a very badly preserved 464, case was damaged by solvents and was in a very sorry state. I wasn't expecting much but when I powered it up I got the basic screen immediately. I've powered just the motherboard by jumpering 1 and 3 as the tape deck is in a bad shape and need servicing.
As said I got the blue and yellow basic screen however when checking voltage rails and signals, I noticed that the +5V was actually measuring +4.0V, CPC was connected to my bench PSU which was delivering a stable 0.750A on a setting of 5.02v@1.5A so there does not seem to be a short and current does not seem too high. I can't do too many tests until I reassemble everything chips temperatures seems fine, CPU and the video chip are hotter than others and the yamaha is slightly hot, while all others are cold to the touch. Caps are all ceramic, with only one electrolytic that does not seem damaged ... so, is this nominal?
Considering at the moment I have no way to load programs into the computer except typing them with the keyboard, is there any kind of diagnostic rom that will perform a more in depth check?
BR
I am not so familiar with the Amstrad CPC and I am testing a very badly preserved 464, case was damaged by solvents and was in a very sorry state. I wasn't expecting much but when I powered it up I got the basic screen immediately. I've powered just the motherboard by jumpering 1 and 3 as the tape deck is in a bad shape and need servicing.
As said I got the blue and yellow basic screen however when checking voltage rails and signals, I noticed that the +5V was actually measuring +4.0V, CPC was connected to my bench PSU which was delivering a stable 0.750A on a setting of 5.02v@1.5A so there does not seem to be a short and current does not seem too high. I can't do too many tests until I reassemble everything chips temperatures seems fine, CPU and the video chip are hotter than others and the yamaha is slightly hot, while all others are cold to the touch. Caps are all ceramic, with only one electrolytic that does not seem damaged ... so, is this nominal?
Considering at the moment I have no way to load programs into the computer except typing them with the keyboard, is there any kind of diagnostic rom that will perform a more in depth check?
BR
#3
Consequently, we can also replace : LD BC,#0000 :source_skip ;; Skip bytes in source data.
with
LD C,0 :source_skip
since the B' register will always be 0 after the loop, and the C' value will never be greater than 6.
with
LD C,0 :source_skip
since the B' register will always be 0 after the loop, and the C' value will never be greater than 6.
Code Select
ORG &AFC3
y_loop:
LD A,C
EXX
LD B,A ;;B'=x_loop counter
x_loop:
LD A,(DE) : INC DE ;; Load sprite data and update source pointer.
OR A : JR Z,$+3 ;; Is byte opaque?
LD (HL),A ;; Write byte.
INC HL ;; Update target pointer.
DJNZ x_loop
EX DE,HL ;; Swap registers to allow DE=DE+BC.
LD C,0 :source_skip ;; Skip bytes in source data.
ADD HL,BC
EX DE,HL
LD BC,#07FA :target_skip ;; Go to next row and skip bytes on screen.
ADD HL,BC
BIT 6,H ;; Was the screen memory left?
jump_condition: JP Z,$+7
LD BC,#C040 : ADD HL,BC ;; Then correct target pointer.
EXX
DJNZ y_loop #4
Thank you for the comments.
In the AFC3 loops, I think we can get rid of the following instructions:
EX AF,AF' ;; Restore A.
DEC A : JP NZ,x_loop
and use the register B' as a loop counter. The BC' register is overwritten just after, as we can see.
So the code would become :
I have not tested it yet.
In the AFC3 loops, I think we can get rid of the following instructions:
EX AF,AF' ;; Restore A.
DEC A : JP NZ,x_loop
and use the register B' as a loop counter. The BC' register is overwritten just after, as we can see.
So the code would become :
Code Select
ORG &AFC3
y_loop:
LD A,C
EXX
LD B,A ;;B'=x_loop counter
x_loop:
LD A,(DE) : INC DE ;; Load sprite data and update source pointer.
OR A : JR Z,$+3 ;; Is byte opaque?
LD (HL),A ;; Write byte.
INC HL ;; Update target pointer.
DJNZ x_loop
EX DE,HL ;; Swap registers to allow DE=DE+BC.
LD BC,#0000 :source_skip ;; Skip bytes in source data.
ADD HL,BC
EX DE,HL
LD BC,#07FA :target_skip ;; Go to next row and skip bytes on screen.
ADD HL,BC
BIT 6,H ;; Was the screen memory left?
jump_condition: JP Z,$+7
LD BC,#C040 : ADD HL,BC ;; Then correct target pointer.
EXX
DJNZ y_loopI have not tested it yet.
#5
General Discussion - Introductions / Re: New 3" disks? Floating an ...
Last post by eto - Today at 13:33Quote from: ZorrO on Today at 12:55very low margin? - I don't think so. There's about 2mm betweenI primarily meant that I would expect that the circle must be close to perfect to avoid being unbalanced and that the foil doesn't get any buckles when being cut.
But I might be wrong with that assumption.
#6
There are problems:
- the cartridge doesn't have a write signal
- the cartridge doesn't have access to z80 signals for I/O
therefore very limited by communications with the cart and any communication operations would need to be done by reading from various rom addresses.
It may be possible to be creative and run a pi on the board and the software runs on the pi AND this pi has a video output.
What would be possible is to attach the PI to expansion of the Amstrad with the software on the cart but then this would not work on GX4000 but would work on CPC and Plus.
- the cartridge doesn't have a write signal
- the cartridge doesn't have access to z80 signals for I/O
therefore very limited by communications with the cart and any communication operations would need to be done by reading from various rom addresses.
It may be possible to be creative and run a pi on the board and the software runs on the pi AND this pi has a video output.
What would be possible is to attach the PI to expansion of the Amstrad with the software on the cart but then this would not work on GX4000 but would work on CPC and Plus.
#7
I've tried anthracite grey as the can was really cheap, actually result is not bad... it looks different (as clearly seen comparing two cases - above is the painted one) but much better than a discoloured original one. I may order a RAL 7020 if I find a good deal but for now will do. The bottom of the case instead is most definitely a 9004 signal black. It's just identical.
#8
General Discussion - Introductions / Re: New 3" disks? Floating an ...
Last post by ZorrO - Today at 12:55very low margin? - I don't think so. There's about 2mm between track zero and edge of foil, and also over 1mm between edge and space inside case. So you could cut manually with scissors in a wavy line 1mm wider or narrower than original 3" drive and it would still be fine. You could also turn on rotation on an open 3.5" drive and mark line with something thin and sharp, then cut from there. I don't think it would be a huge challenge.
#9
Hi,
Dumb question for the hardware guys, could we do the same thing like Doom with SuperFX3 for the SNES but with an Amstrad CPC cartridge ? It is using a Raspberry Pico2 2350.
The difficulty I suppose, would the cartridge with a 2350 have enough electricity to work, without endangering a CPC (with the Plus2CPC or Play2CPC), GX4000 or CPC+ alimentation ?
Or can the cartridge have it's own alimentation maybe ?
Not related, but 15 other posts and bingo !
Dumb question for the hardware guys, could we do the same thing like Doom with SuperFX3 for the SNES but with an Amstrad CPC cartridge ? It is using a Raspberry Pico2 2350.
The difficulty I suppose, would the cartridge with a 2350 have enough electricity to work, without endangering a CPC (with the Plus2CPC or Play2CPC), GX4000 or CPC+ alimentation ?
Or can the cartridge have it's own alimentation maybe ?
Not related, but 15 other posts and bingo !
#10
I'm really curious how that looks on a normal CPC without the different colours and smaller screen size.
Just recently I thought that I might give Quigs a try and this makes me even more interested.