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#1
Problem is solved by replacing chip with 74HC240B1, original was 74HC240N.
For future references that came here looking for solution:
Few things to note here - without chip computer works but gives "Isp" instead of brand.
Do not worry about this, it's mechanism to detect certain brands based on detected hardware instead of four contact (LK1, LK2, LK3, LK4). Dump from ROM is this: Arnold Amstrad Orion Schneider Awa Solavox Saisho Triumph Isp - so this is the list of all supported brands. Have nothing to do with ROM, don't change it, it's most likely fine.
Next, this octal buffer/driver is very simple device, but logic from FDC will behave differently based on the state of this chip. If you remove whole chip you get kinda delayed initialization, not hang or anything. If whole FDC is removed you will see no change until you run command, then you will see red screen.
My exact problem was really a short in this chip of 1A1 and 5V VCC. Good thing that levels are the same everywhere so other electronic didn't die because different voltage but instead input signal from RDAT (read data) is overriden by short instead going down and up representing digital levels. Using osciloscope you will read "a try" to low the signal but it will happen for a very short period of time, not enough for digital signal there.
I came to conclusion like this tracing RDAT line from floppy. At first I tought it's FDC pin where this goes, but it's not, it's this buffer first and then SED9420CAC (CMOS data separator) and then to FDC. Good thing that I followed schematics and not trying to trace hard way.
Looking at logic of this chip most likely it will die with short with 5V, other possible case is floating line. So my advice is to test short from 5V to other pins. No other pins is shorted to 5V (when you see datasheet for buffer you will see it cannot work that way).
When soldering chip, first solder 20 pin socket in case it dies again and chance of dying is quite high because it's first in the line from floppy drive and a lot of things can happen during that transfer, from bad/dead floppy to interference (my centronics floppy cable was 1 meter). Take care of resistor array near it, do not push it hard.
When you put replacement in socket first measure if short is gone, then turn it on without floppy and measure signals again, 5v and input/output, and after than you can connect floppy and try to read something from there.
Hope this helps someone.
#2
I noticed that unidos supports 2 Albireos in the 1 cpc.  Do I need to configure the hardware to allow that or is there a variant albireo thst is needed for 2?
#3
Forgot to mention, there is also a cartridge emulator board to play biggest games, if someone wants to get it now and save some shipping, it is 25 euro.
#4
PM sent
#5
Hope this is OK as it's not CPC specifically.

I've got a PCW9512 which uses an EME-232V drive. I bought a CP/M disk but it didn't work so, on the assumption the disk was OK (it proved to be OK - see below) I assumed that the drive was out of kilter and needed calibrating.

I also changed all the caps because that's the camp I sit in. :D 

At some point during the calibration the drive died. It was properly dead with no signs of life. I tracked it down to one of the current protection devices (Q4) and after installing a - ahem - temporary fix, the disk would spin but there was no head movement.

After a lot of faffing I traced that fault to the transistor that sits between the legs of the stepper drive chip, located at Q6. I replaced it and, wonder of wonders, the head began to move again.

So I continued trying to calibrate the drive but with no luck. Either the drive would seek slowly and then I'd get three beeps and a white screen or, if I was lucky, I could get it seek repeatedly as if it was close and I'd get four beeps and a white screen. And then, while I was holding the drive and trying to twist the stepper motor by the tiniest of amounts, I got a couple of lines appearing on screen. Then a re-seek and a few more appeared. Long story short the disk booted to CP/M and I thought I'd cracked it.

But I hadn't. To cut this three week story down a bit more, I've reached the point where the thing will boot every time but ONLY if the drive is on its side. Doesn't matter which one, but if it's on its side then it will boot. It's not 100% and there is plenty of seeking that goes on but it does eventually boot every time.. The question is, why? Anyone got any ideas?

#6
avatar_Dwalin
Games / Re: Los Elfos de Maroland
Last post by Dwalin - Today at 14:09
Quote from: Gryzor on 11:00, 29 April 23Ah a pity it's Spanish only...
Now avaliable in english too:

https://rudolphinerur.com/elves
#7
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#8
Hi there!

Do you want a modern clone of the Vortex F1-D floppy controller?

What is it?
- Works like the Vortex F1-D floppy controller, this means it's supported by FutureOS.
- Four drives can be connected (E, F, G and H under FutureOS)
- 40/80 tracks, one or two sides
- FDC765 floppy controller and FDC2992 data separator (like in the CPC6128)
- Floppy controller card is in MX4 format and fits on Mother X4
- No ROM on controller! Makes it smaller :-)

Actually you can use it only with FutureOS.
And now you can buy it for 60 Euros + postage + packaging.

Please contact me via PM if you want one unit.

Greetings!

#9
Ah so you still want 2 colour sprites, but you want to hard-code whether it is colour 1+0, 2+0 or 3+0 into the sprite, converting it to a basic 2bpp? Will you also encode a separate 1bpp mask into this sprite?

If there isn't a mask you also want to inline, could you just write a 1bpp sprite renderer that does the conversion at render time, perhaps with sprite number as one argument, destination X,Y or address as another, and pen as a third? TBH this is what the CPC firmware text routines do except they set the pen via a separate call.

Doing it manually in asesprite in tiled mode might take a little time, but you could add dithering or spot colour effects.
#10
PM sent  :)
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