Recent posts

#1

News & Events / Re: Benediction Coding Party #...

Last post by norecess464 - Today at 11:53

Registered!

#2

Technical support - Hardware related / Re: Amstrad GT65-2 Green Scree...

Last post by tibbs1972 - Today at 06:49

Goods news this morning, after presenting the facts, I've been offered a refund and an apology, all's well that ends well. 

#3

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Games / Re: The Dark Knight [ wip ]

Last post by trocoloco - Today at 01:03

and another cdt nobody asked for either  . Loading version with rasters, compressed files in "just" 2:20 minutes of loading time 

#4

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News & Events / Benediction Coding Party #5 | ...

Last post by toms - Yesterday at 22:39

The Benediction Coding Party is back! The 5th edition will take place from October 30th to November 2nd 2025 in Gavray-sur-Sienne (50450), France. Get more information and register on the official website!

Don't miss the biggest Amstrad event of the year!

#5

Games / Cheril Perils by The Mojon Twi...

Last post by Jean-Marie - Yesterday at 22:18

Thanks to Chema for the heads up. No download link yet.

#6

Technical support - Hardware related / Re: Amstrad GT65-2 Green Scree...

Last post by tibbs1972 - Yesterday at 21:21

Hello Bryce,

Yep, seems like the Diodes were removed or the vendor swapped it with another Monitor.

I've seen plenty of damaged circuits in my time, I don't think the Diodes blew, all was left was legs and no sign of other damage on other components, no Black marks, or any melted components.

I've attached the picture of it working from Ebay.

Luckily for them, I wanted to clean it up and refurbish it in any case. It gave me a bit more experience working with monitors as well.

Just glad I could fix it and that I could find circuit diagrams on the internet.

Regards
Tibbs

#7

Technical support - Hardware related / Re: Amstrad GT65-2 Green Scree...

Last post by Bryce - Yesterday at 20:29

That's pretty nasty. The monitor could never have worked without them, so the seller took photos of a working monitor and then removed the diodes??

Bryce.

[NINJA COMMANDO]

#8

Games / Re: Converted GX4000 .cpr - Th...

Last post by iXien - Yesterday at 20:02

And a new one, sad that it isn't as good as the original C64 version, but it remains nice to play :

NINJA COMMANDO from Zeppelin Games

Controls:
J1B1 = Fire
J1B2 = Jump
J2B1 = Pause/unpause game

Modifications for the GX4000 version:
    - New title screen based on the one in the C64 version ,
    - Wait for fire on title screen,
    - All game keys patched (including jump moved from up to fire 2),
    - Broken pause feature fixed,
    - Pokes : Invulnerability or unlimited lives.

[it ends part way through track 39]

#9

Technical Support - Software related / Re: Bomb Jack Extra Sugar hang...

Last post by ikonsgr - Yesterday at 19:53

With Anthony's DSK all looks normal. PROGD has a valid amsdos header and it ends part way through track 39. The disk also looks standard 40 track AMSDOS based disc.
With ikonsgr's dsk the files are arranged differently due to formatting and copying and data goes up to track 23.
So the only difference I believe is where on the dsk PROGD ends in this case.

The phrase in bold, reminded me of something: After 765 Floppy Disk Controller (for the brave and bold... see Table 6.),  finishes reading a sector, Sector Number stored in R (each sector is determined by 4 sector id bytes, C-Track, H-head, R-Sector, N=sector size), is incremented by one (e.g. placed to next sector), BUT,in case of reading the last sector of current track, the C-Track s incremented instead, and R-Sector placed to the 1st sector of the next track! Of course, this how i implemented the FDC emulation code...
 But, WAIT, what if we read the LAST sector of the LAST track? Did I provide a provision in the code for this case?
 Well, it proved that i DIDN'T, and because of that, if the LAST sector of the LAST track of a dsk image is accessed, C-track was increased to a non-existent track, and next read/write operation would seek a non existent point in dsk image file, resulting in PIC MCU code execution to fall into an endless loop as it waited for ever a proper respond from usb host module, that never came=fatal hang up!
 Now, some of you might wonder: Why after so many years, this bug was never found?
Well, because the only way to discover and fix this nasty bug (or more accurately, an oversight in the code...), was if the LAST sector of the LAST track is requested from a program/game in a dsk image! And as it seems, this happens VERY RARE (most probable because almost no dsk image is fully written with data), apart from "Bomb Jack Extra Sugar" image, the only other case i encountered having exactly same behavior (fatal hang up upon reading dsk image with no obvious reason), was the "Little Computer People" dsk image!
 As soon as i fix the bug (simply by adding a code that, in case of last sector of last track is accessed, "next" track will reset to Track '0'), both games loaded without problem from the dsk images!
 I uploaded firmware updates (4a), for updating using serial cable or PICKIT programmer  for anyone wanted to play Littl Computer People on CPC 464.
 Thanks again to @arnoldemu that his remark, was the trigger to make ULIfAC board a little better, at least "Little Computer People" better! 

Btw, if anyone encountered this fatal hang up, upon accessing a dsk image, it would be very nice to tell us about it  and see if problem is fixed.

#10

Technical support - Hardware related / Amstrad GT65-2 Green Screen Mo...

Last post by tibbs1972 - Yesterday at 18:11

Hi all,

I purchased a GT65-2 Green Screen monitor on Ebay a few weeks ago for nostalgia, as that's what I had as a child.

On the website photos, it worked, but when i received it, it didn't.  Beware Ebay. 

For £50, it was worth the risk.

Anyway I took it apart and had a browse inside after discharging the tube.

I spotted 2 Diodes missing, they looked to be cut out intentionally, maybe used elsewhere, they were D704 Hitachi V09C and D705, Hitachi V06C. 

These are general purpose rectifiers dodes, luckily datasheets still exist online.

I found some UF5406 3Amp 1.7V diodes online to replace them, which I've just done. D704 feeds the Flyback transformer.
  
D705 looks like its the Flyback Diode handling voltage spikes and feedback when the transformer de-energises.

So far everything is working and I've tested with my CPC6128. Fingers crossed this did the job. The new diodes are overrated, but are doing the job required.

Now I need another project to repair/refurbish. Back to the web to browse for another project. 

Regards
Tibbs