Reply 60 of 106, by Jo22
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wrote:Our first family PC was an Amstrad PC1512 which had a clone CGA onboard. It didn't have a real CRTC so a lot of tricks were not […]
wrote:For example, back in time. clone cards and Mono/Color combo cards were seemingly more common in Germany than IBM CGA cards, I believe.
Not sure about the UK, though or why it was that way at all (if it was, my memories are a bit sketchy).Our first family PC was an Amstrad PC1512 which had a clone CGA onboard. It didn't have a real CRTC so a lot of tricks
were not possible, and it didn't have any improper modes either (I know, I tried all possible mode register values in an
attempt to find new modes). It used NTSC-compatible timings if I remember correctly, but didn't have any kind of omposite output.
Cool, the PC1512 was also popular over here! 😀 It was sold under the Schneider brand but was otherwise identical.
It wasn't until the Euro series (Euro PC, Euro AT, Tower AT, etc.) that they went their own ways. Luckily, the Amstrad PCW was also still sold here.
It was called Joyce and was an interesting "typewriter" running on CP/M. It was also occasionally seen in the Doctor Who series, I read.
My father had a PC1512, too. I believe it was his first IBM compatible machine that he got.
If memory serves, he upgraded it with a V30 processor (it was 8086 based) and used it to run his older
Z80 stuff he wrote for university via Z80MU, a popular CP/M emulator of the time. If he only knew about 22nice,
he could have used the 8080 emulation mode (minus the Z80 opcodes).
I also recall he liked 1512's graphics abilities and the GEM system that came with it.
In some way or another the PC1512 was like an "European Tandy", I think.
I read a bit about its CGA derivative at seasip. I'm not 100% sure, but I think I've heard
that the succesor of it, the PC1640 with EGA, still had that custom CGA circuit left intact on the PCB.
It was simply disabled somehow.. Anyway, I can't check, because I don't own such a system.
wrote:wrote:The best we got in terms of CGA was CGA in 4 colours via RGB. On the bright side, this allowed many SCART-equipped TVs to be used as CGA monitors.
I never saw this but I have heard that it was done (at least sometimes the intensity bit was not wired up at all so you just got 8 colours). I seem to remember that the school BBC Micros in the late 80s (possibly also mid 80s) used SCART leads to connect to their monitors too.
I admit that XT hardware was a bit before my time, so I'm not 100 percent sure and have to speak under correction,
since I haven't seen that much of actual period-correct hardware from the original PC generations.
(Thankfully, I was allowed to still grew up with some CGA games, at least. 😁 )
My information was mainly based from what I heard from my father and his amateur radio friends.
Apparently, these custom SCART leads were popular to some degree here (also for other platforms, Commodore 128, etc).
I remember I've seen different schematics of that type a few times in these old radio magazines, too.
The CGA-SCART lead I remember of was printed in Elektor magazine. It was very simple.
And, as you mentioned, didn't take care of the intensity bit, so it was really just "RGB" (no RGBI).
If I had to guess, these SCART mods were probably kind of popular because people here had no proper CGA equipment,
but lots of clone cards from Taiwan. So people were happy with any picture output that was sharp and in colour.
Maybe the Commodore Amiga monitors also contributed to that, since they had RGB right from the start.
But that's pure speculation. As I said, it was a bit before my time. 😅
wrote:wrote:Edit: I apologize for the long post. Just realized how long it really is. 😅
I hope you don't mind. I didn't mean to overrun your thread.
I'm too chatty sometimes (a bad habit of mine, my sister says).No worries - if a thread drifts too far off-topic it can always be split off. I think this is all relevant though.
Whew!, glad to hear! 😀 More than often, I'm worried to overdo things because I like to share as much information as possible.
Partly it is also because, in my family, it's often my turn to entertain people (friends, relatives, acquaintances) that visit us,
because else the living room would become a quite place rather quickly (these people rarely bring in topics on their own sadly).
I guess that's why I developed that habit over time. That's why I'm often worried that people not knowing me personally,
especially folks over the internet, could mistaken me for having a bad personality or something like that, hah. 😅
wrote:[..] i have no idea if these will work on an older machine but they're fun to make [..]
Hi, yes, I believe so. That last picture seemed to work out nicely, IMHO.
Simply converted it to a CGA Binary without any further changes and then
displayed it with a BLOAD utility on an XT class machine with on-board CGA.
A short clip can be watched here (I zoomed in a bit) : https://youtu.be/ReaG6FmSlns
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