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ready.
Registered: Feb 2003
Posts: 441 |
C128D - 1571 drive compatibility with demos
Hi,
I just got a commodore 128D, with built in 1571 drive. As far as I read this drive should emulate the 1541 in c64 mode, but... I experienced a few crashes running certain demos. So far Deus Ex Machina and Insomnia both crash right after turning disk side. Risen from Oblivion V2 runs fine in C128 mode.
I thought about a not 100% correct emulation of the 1541 in c64 mode.
Has anybody had the same problem?
thanks,
Ready. |
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Krill
Registered: Apr 2002
Posts: 2968 |
The 1571 in the C128D(CR) is a bit odd and a bitch when it comes to compatibility. People are aware of that, but keeping stuff compatible is a little tricky. |
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ready.
Registered: Feb 2003
Posts: 441 |
Has anybody tried to mount a switch to disable it and work with an external 1541 set as drive 8? Somewhere I read it is possible, but there was no feedback about it.
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MagerValp
Registered: Dec 2001
Posts: 1074 |
Putting a switch on the 1571DCR's ATN line should do the trick.
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Oswald
Registered: Apr 2002
Posts: 5086 |
deus ex worked fine on my c128dcr. |
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Steppe
Registered: Jan 2002
Posts: 1510 |
Works here too. Drive misaligned? |
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ready.
Registered: Feb 2003
Posts: 441 |
Hi,
I think it might be that I touched the head stop adjustment by mistake. I released the screw that holds the stop mechanism on the step motor shaft. Is there any chance to re-tune it? The drive reads, but with some difficulties.
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
Uhm drive alignment is quite some trouble. It requires an Oscilloscope or some other suitable measurement device and an alignment disk. |
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Steppe
Registered: Jan 2002
Posts: 1510 |
Bah, just turn that screw until it works again... ;-) |
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enthusi
Registered: May 2004
Posts: 677 |
tapes ftw |
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ready.
Registered: Feb 2003
Posts: 441 |
yeah, I guess that the "turn the screw until it works again" is the cheapest and most reliable method. But before that I'd like to have a look at the canonical procedure on how to do it. I tried to google for it but I haven't found any good instruction. Does anybody have such a thing, please?
thanks,
Ready. |
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raven
Account closed
Registered: Jan 2002
Posts: 137 |
Insomnia was 100% done on my 128D, including the loader.
The 1571 is the only drive that didnt cause any problems
with the older version of the loader.
It also didnt crash only on the 128D at the partyplace.. heh
The only difference i know of, from tests i've done, are
when using the 2bit+ATN protocol.
On the 1571, two (sometimes one) extra cycles of delay
are needed between serial bus reads on the 64 side.
Other than that, it *should* work the same, in theory
atleast :)
Btw, can you measure the RPM of your drive? there's a tool
that can do that, the name escapes me though.. |
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Devia
Registered: Oct 2004
Posts: 401 |
@ready:
Use 1541-tester for Head Stop alignment: ftp://ftp.zimmers.net/pub/cbm/documents/disk-drives/1541-tester..
..it's option '6' in that prog. (you will need the original calibration disk for that prog to use any of the other options, IIRC)
If you need to do drive alignment, i.e. re-adjust the stepping motor position, you can use various utils.. Personally I have used an oscilloscope and some simple basic proggy for that, but I know there are just as good, if not in fact better options to adjust without a scope.
Check out ftp://ftp.zimmers.net/pub/cbm/documents/disk-drives/ ..there're some text files in there, that might explain some things.
Basically you have to know what you're doing ;-)
The head stop align-thingie in that first prog will explain what to do for that particular job. You won't need any disks.
For alignment of the stepping motor you will however need a "known good" disk. I.e. a disk formatted and written in a drive you'd consider to have a "reference" calibration.
The actual calibration is FRUSTRATING, to say the least.. everything is connected to everything and nothing is calibrated once you tighten all the screws again or flip over the drive so it's no longer upside down.. Bottom line: It requires some experience to do it properly ;)
..but you should be able to align the head stop using that first prog though.. it's not that difficult.
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ready.
Registered: Feb 2003
Posts: 441 |
Thank you very much Devia!! I'll give it a try as soon as I have some time. I agree with you, it's always better to know what I'm doing, that's why I'd like to learn how it works before putting my hands on it.
I'll let you know how it goes.
Cheers,
Ready. |
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ready.
Registered: Feb 2003
Posts: 441 |
Finally I had my C-128D drive fixed. It was easier than I though: the problem was that the metal rail on which the drive heads run on was sticky and dirty. Pulled it out, cleaned it with alcohol and now Insomnia works great!! Even if the drive cannot pass the drive test in the Insomnia demo engine.
Now I have also a 1571 external drive. It was for the US market, so on bottom it says Power 117V AC 60Hz. Here in Italy we have 220V 50Hz. Some electrical equipment don't care between the 2 standards and work regardless 50Hz or 60Hz. But how does the 1571 cope with this? Has anybody ever tried?
thank you,
Ready. |
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Devia
Registered: Oct 2004
Posts: 401 |
Haven't got a 1571 by me right now, but since the so called "Universal Power Supplies" capable of handling 110-240V @ 50-60Hz didn't get common until recent years, my bet is that you will fry the thing trying to supply it with 230V. - unless they buildt in a 110/230V manual switch like you see on most AT/ATX power supplies. |
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null
Account closed
Registered: Jun 2006
Posts: 645 |
or get an inverter/converter/adapter/whatever
------------------------------------
http://zomgwtfbbq.info |
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Style
Registered: Jun 2004
Posts: 498 |
Ready: thanks for that, I have a 1571 here that I think suffers the same issue you described - Ill pull it apart and clean/regrease the rail and see what happens. |
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Style
Registered: Jun 2004
Posts: 498 |
Actually, how do you align a drive with an oscilloscope graham?
I have one right here.
Im guessing, with a suitable alignment disk, you could measure the output of the read head and tune?
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
Best would be to use a program in the drive which bumps the head to track 1 and then simply reads the disk + prints track number on screen all the time.
Then use your oscilloscope to get a maximum signal of track 1. |
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Style
Registered: Jun 2004
Posts: 498 |
Ill look into it - I wouldnt mind restoring this 1571 back to new condition. |
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ready.
Registered: Feb 2003
Posts: 441 |
Actually I think it's best to clean with alcohol and not grease it at all, it works fine as long as it is well cleaned. Further more I think that cleaning just the right rail (looking from the point you insert the disk) can be enough. Pulling the rails out is not so easy, especially the left one. If you hit the drive head by mistake....your drive is dead. So the less you mess around it, the best for your 1571. |
