pouët.net

Since I now have abandoned my quest to buy a Sam Coupé (holy crap are those expensive!), I feel the need to get another machine to keep me entertained.

Now, an Amstrad CPC is something I've been pondering for long, and being able to watch Batman Forever and the Vanity demos on real hardware would be ace.

So...Looking at what model to get, I'm guessing the 6128 is the way to go, since it has the 128kb RAM and the diskdrive which I guess is needed for most demos.

Then, however, there is the issue with the CRTC-version. It seems like some models is completely worthless when it comes to running demos, and there doesn't seem to be a good way to know which chip is in a machine without running specific tests which would require a special program transferred and run on the machine in question (ie. good luck getting a random eBay seller do that...)

How can I find a "correct" 6128?

Just get a 6128 with the new Amstrad logo (the one with a diagonal band crossing AMSTRAD word).

Those have the Batman's CRTC that you are looking for.

Heh, I was unable to buy Sam Coupe too, but recently saw a CPC6128 plus which was also very expensive (but more rare to even appear) and threw like 400 pounds (Shut up and take my money!). I don't regret it. I became more tolerable at buying stuff now, so I might get the Sam Coupe too after 2-3 months. One is appearing per week but always go over 300. But yeah, they are damn expensive.

But back to the question, if you get a random CPC 6128, most of the time is CRTC 0 or 1, you have to be unlucky to get others (actually all of mine are CRTC 1 which is good, but wanted in the past a CRTC 0 for Shadow of the Beast preview demo, which was ported recently to CRTC 1. And also From Scratch is only CRTC 1 so maybe this is the best model. But you can't know it from first sight.

Also, I got duped, found a CPC which happened to have extra memory chips corrupted, but seller couldn't know this, because 99.9% of games just work fine with 64k, but not demos. Anyway, got another one now and it's great.

There is this basic listing to detect. Problem is I never was able to convince seller to type in this program and tell me. Or could test with some demos, but you have to convince the seller again and provide the disks and maybe the drive doesn't work. Usually the 3" drive doesn't work (but one just needs to change a rubber band) from any CPC I bought, but as I fit 3,5" or Lotharek's SDHc I don't care about the old drive.

So yeah, it's not easy to know if you don't have access to the machine but most of the time it's one of the more common CRTCs unless you are unlucky. Maybe there is also a higher probability for a type, depending if you buy from France or UK? I don't know.

The listing code is not mine btw, I am not the author, just provided from other sources.

Get a floppy emulator from Lotharek. The real floppy drive is only for decoration and nostalgia.

To clarify:

Old logo, CRTC 0 or 2



New logo, CRTC 1 or 4 (but type 4 is very rare!)


Go for CRTC 1!

But CRTC 0 is not so bad. Still a lot of demos work.

what is it?

@g0blinish: A fancy SD card reader.

You can also put a 3.5" disk drive in your CPC.

Didn't know that about the logos.

Thanks for all the info!

Turns out that the CPC I had been eyeing on eBay had the old logo, meaning there is a risk for CRTC2. Guess I'll have to pass one that one.

As a sidenote, those Spanish models have a funny, really stiff keyboard unlike the normal ones.

The first 6128 old logo I bought is a CRTC 2, my first new logo is a 4 :D

I prefer the old logo and finally I have a 0, I didn't knew that the sotb preview was adapted to CRTC 1!
CRTC 1 seems to be the one for demos.

The case is a little different on CRTC 4 and it's wrote version "0" on the little round sticker on the back. Near the video output you can see the green PCB as with every other 6128 but there are 2 large iron parallel horizontal lines...

The seller sent me a picture of the CRTC chip!



Reading the table here this seems to be a CRTC1, the "best" one.

However, the machine has the old logo, so according to ham that should not be possible (only CRTC0 or CRTC2 in old logo machines)?
Could there be some old-logo machines with CRTC1, or am I identifying the chip wrong?

Or maybe someone swapped the mobo? :)

Yeah, that's a possibility of course, or swapping the chip itself.

Well, I was too late anyway, it was sold already. :(

This is a surprise. Yes. That "R" in the chip is the mark of "type 1 CRTC".

I didn't knew that some CPCs with the old logo could have that chip.

I was wrong... Or maybe the motherboard was replaced, as britelite said.

Anyway, I wish you more luck next time in your searching.

Got another CPC that I'm looking at now, but it is CRTC0. Still, if I understand things correctly most demos will run on that, with the exception of "From Scratch" by Vanity?

Yep.

To be honest, in reality you could get pretty much any CRTC chip in any CPC. Officially all of these chips were interchangeable, it's just some of them have different behaviours when you do unexpected things. The datasheets for the different chips actually describe the same behaviour as each other, more or less...

As the parts were nominally equivalent, it'd come down to which was cheapest and/or in stock at the time a batch was purchased. That said, the Motorola part tended to be most common in the early days and less common by the time the 6128 was available. As luck would have it, this is the chip that most demo programmers consider the "worst", even though it's the original chips that the others are imperfect clones of.

So I bought the one with the CRTC0. Really looking forward to seeing Batman Forever on real HW finally!
I am planning on hooking up my HxC to run stuff from, can I use it as secondary drive and start demos from that, or is it better to replace the internal drive?

Plug it on the external connector. Some demos have trouble running from drive B, but you can ground some pin on that connector to have it override the internal drive completely.

http://www.cpcwiki.eu/index.php/Guide_on_how_to_connect_a_3.5%22_drive_to_a_CPC6128/664

You can pretty much unplug the internal drive anyway and use only the HxC in the external port as drive A. As a bonus, you can then use the power cable of the internal drive for the HxC - but swap the 5V and 12 lines first! At least in my machines the otherwise standard-looking plug has had them reversed.

I used to have a CPC where somehow the HxC didn't work with first drive connected. Maybe it was my mistake, but no switches or |B made it work, so I disconnected the internal drive (which was not working anyway) and it finally worked. But in my current CPC it does work without having to disconnect the drive, and with a cable with switches for 1st/2nd side or A/B drive, it's perfect. I got the cable with full switches from here cause I didn't know or didn't wanted to bother how to solder and make one, but it must not be hard to build one.

If you disconnect the internal one, any standard old PC floppy cable will do without switches.