Posted By
Monty
on 2005-10-03
21:21:51
|  Using Commodore 1541 disk drive on a Commodore + 4
In the plus 4 manual it says you can use a Commodore 1541 [c64 drive] on a Commodore + 4 ...
So .. i linked it up via the seial ports and the + 4 reconizes it kinda as the drive spins when you reset the computer but when I try to boot a +4 disk with DLOAD"*" [which I made on star commander] it says loading on the screen but the disk drive dose nothing do I need a special lead? Im using the serial lead I use to connect my c64 and 1541 drive and they work fine together on my Commodore 64 .. Am I doing this wrong? do I need to use a commodore + 4 disk drive insread? Any help would be appriciated ..
Also one other thing are .d64 images also used for +4 disks or is it some other format? I keep seeing .G64 popping up on the site here .. is that the commodore +4 disk image ext? please if anyone can shed some light on this I would be very appriciative as I been trying for a while now to convert +4 games back to 5 1/4 disk with no luck 
Many thanks Monty ^_^
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Posted By
JamesC
on 2005-10-03
22:18:24
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Monty,
The 1541 works with the Plus/4 just fine. When you first turn the drive and computer on, the disk drive should turn its red light on during its diagnostics (it also checks for a disk and reads in the BAM if a disk is found). After the red light goes out, type PRINT DS$ to verify that the drive is talking to the computer correctly.
DS$ is a built-in variable that reads the drive's error channel, much like INPUT#15,A,B$,C,D did on the C64.
If you can't get a DS$ back from the 1541, then check the cable to make sure it's firmly inserted at both ends. Also, the 1541 won't share between two controlling devices, so it can't be hooked up to the PC at the same time (remove the X-1541 cable at the 1541 end while the drive is turned off). Also, certain printers on the bus will interfere if they're connected but not turned on (the 1525 is known for this problem).
If you need further help, just ask!
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Posted By
JamesC
on 2005-10-03
22:28:01
| Re: Using Commodore 1541 disk drive on a Commodore + 4
I forgot to answer the second question..... the Plus/4 doesn't care if it's a .d64 or a .g64, those are disk image formats for Star Commander to deal with. If Star Commander is writing C64 disks that you can read with your 1541 and your C64, then it can write Plus/4 disks. Once it's on a 1541 disk it's no longer a .d64 or a .g64, it's a disk.
Be sure that you are trying to load Plus/4 versions of programs (sometimes a boot program that detects the right computer and loads the appropriate version isn't the first program on the disk). Look for a short 1 or 2 block program near the beginning of the directory, sometimes they're labelled "BOOT" or "START" or "1" or "LOAD" or something that tells you to try this program first.
Ideally the booting program is the first program on the disk, but not always.
Also.... if you've accessed a file on the disk already, then you do a DLOAD"*", the drive will try to load the last-accessed file. If you've just read a sequential file, then it'll try to load that file again, and it can't cause it's not a program. The 1541 should blink its' red light at you in this instance, and you can PRINT DS$ to see the error message.
To always access the first file on the disk, use DLOAD"0:*". This forces the first file on the disk to be loaded, and also reminds the 1541 that it's drive 0 of unit 8. (Sometimes the 1541 gets confused and thinks it's drive 1, there are a couple of bugs in the 1541 ROMs.)
Alternately, you can hold down the SHIFT key and press RUN/STOP. This does the same as on the C64 but from disk instead of from tape.
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Posted By
MONTY
on 2005-10-03
23:27:38
| Re: Using Commodore 1541 disk drive on a Commodore + 4
[The 1541 works with the Plus/4 just fine. When you first turn the drive and computer on, the disk drive should turn its red light on during its diagnostics (it also checks for a disk and reads in the BAM if a disk is found). After the red light goes out, type PRINT DS$ to verify that the drive is talking to the computer correctly.
DS$ is a built-in variable that reads the drive's error channel, much like INPUT#15,A,B$,C,D did on the C64.
If you can't get a DS$ back from the 1541, then check the cable to make sure it's firmly inserted at both ends. Also, the 1541 won't share between two controlling devices, so it can't be hooked up to the PC at the same time (remove the X-1541 cable at the 1541 end while the drive is turned off). Also, certain printers on the bus will interfere if they're connected but not turned on (the 1525 is known for this problem).]
Ok ive tried PRINT DS$ and it gives nothing back, I have took all other connections out to see if this would solve the problem and still the same thing, I even tried my 1541 II to see if it made any difference but it did the same with that drive too. the red light comes on, then the green and then after that no disk drive movement. both of these drives work fine with my c64 which i fond strange .. my + 4 as far as I know isnt faulty its virtually brand new & minty ^_^
Also my 1541 is actually a VIC1451 would this make any difference? also is the 1541 II drive compatible with the +4 too ? maybe I just have 2 drives that arnt compatible??
getting stressed MONTY lol
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Posted By
MONTY
on 2005-10-03
23:29:06
| Re: Using Commodore 1541 disk drive on a Commodore + 4
sorry I meant a VIC1541 ..
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Posted By
MONTY
on 2005-10-03
23:48:46
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Ok after carefull inspection this disk drive looks like a regular beige original C/64 drive but on the back of the unit it says Model:VIC1541. I dont know if this would make any difference seeing as it works great on the C/64.
Im using the 1541 II drive linked to pc via star commander and the other is connected to my plus/4. I have no printers, I even changed back to rf lead rather than scart lead to see if maybe that was the problem but still not right
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Posted By
MONTY
on 2005-10-04
00:06:25
| Re: Using Commodore 1541 disk drive on a Commodore + 4
http://members.sparedollar.com/ty62/DSCN0211.JPG
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Posted By
JamesC
on 2005-10-04
00:09:51
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Monty,
For our purposes, a 1541 is a 1541 is a 1541. They'll all work the same on the Plus/4 regardless of minor variations on the nameplate.
When you attach the 1541 to the Plus/4 and turn them both on, do any of the lights on the 1541 come on? The green light (on regular 1541 style machines 1540-1541-1551-1570, or the red light on squared drives 1541-II - 1571) is the power indicator, while the other light indicates that the drive is actively doing something.
If the disk drive comes on and passes its' self-test (no blinking lights after 3 seconds), and you still aren't getting a response to PRINT DS$, then attach the 1541-II to the Plus/4 and run these tests again. This will help us narrow the problem down to either a chip inside the 1541, the cable, or a problem in your Plus/4.
If you absolutely cannot get the 1541 to work with the Plus/4, take it back to the C64 and test it there.... and remember the 1541 won't share, so if it's attached to the Plus/4 and the C64 at the same time, even if one is off, the 1541 won't like it and will refuse to talk to either of them.
Last possibility is that the 1541-II is out of alignment, so its disks can't be read by the old style 1541.... but that won't affect the drive status lights or the response to a DS$ inquiry.
I'll be back in about 7 hours to see how you're doing.
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Posted By
JamesC
on 2005-10-04
00:23:19
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Geez... it's getting late for me (I'm in the States) and I didn't read your message through. It seems that you've already tried my suggestions in my last post.
If I may ask, where did you obtain your Plus/4? Did it come with an original power supply? Are you running it through a step-down comnverter? Your problems, after reading your post more closely, seem to point toward the Plus/4 thinking it's on a different frequency than the 1541s are running.... which could be possible if you have an NTSC machine with a PAL Kernal in it. It'll give you a display but the internal timing will be off.
If you have in NTSC machine with an NTSC Kernal, you'd only get a legible picture on your television if it's a multisync television (capable of viewing NTSC as well as PAL).
And.... do the drive lights glow brightly or are they faint? If they're faint then you don't have full power. A 220 volt machine that's only getting 110 volts will do this... and the original 1541s have dual transformers so it's just a matter of changing a wire to go from 110 to 220 or vice versa. The 1541-II doesn't have this option, you have to use the proper external transformer (which is the same as a 1581 transformer if you ever need one).
Ok I'm off to bed now, I'll be back in about 7 hours.
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Posted By
Monty
on 2005-10-04
01:03:13
| Re: Using Commodore 1541 disk drive on a Commodore + 4
well both drives run ok on the c64, the lights on all drives work as they should when powering up and are bright.[on both drives] as far as I know everything is pal uk as I bought everything from uk ebay and nothing uses stepdown convertors.
When I turn on the drive and the plus/4 the light comes on then it reads the disk briefly which makes me think its not a fault in the plus/4. if i unplug the drive from the plus 4 while its on i get a message saying drive error not found etc so it knows its there although it still won't boot any +4 disks. Im thinking maybe its the image I got it from here and maybe its a copied original and that it won't read it due to copy protection as it may be an exact image copy?
Are there any hacked versions of plus/4 games on this site I can test it with maybe? thats maybe a long shot .. It could be as you said the driver heads but then if it was wouldnt I have a read problem on the lone of the drivs and not the other when connected to the c64?maybe I just have a stubborn plus/4!
could be the lead too although I have 2 and have tested them both ..
Right im gonna give up for tonight before I pass out with lack of sleep lol
night for now ^_^
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Posted By
Me
on 2005-10-04
03:26:04
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Don't Ever Turn on or start a 1541 with a disk in the drive!! That was the surest way to corrupt a directory. Unlike our modern floppy drives on a PC, the 154x series was notorious for writing garbage bytes to a directory during diagnostic/powerup. The 1581 didn't have the problem. Some of the early 1571 drives had the problem. You will note that "autobooting" commie disks didn't happen until the 1571/81 drives became common... Shame on you...
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Posted By
JamesC
on 2005-10-04
07:46:18
| Re: Using Commodore 1541 disk drive on a Commodore + 4
To "Me": If you look closely at the 1541 manual, there is a "bootup" load command referred to as an "ampersand file" (&). This is intended to load a file into the 1541 memory upon power-on.... and the disks Monty is using are generated with Star Commander so they're easily rewritten if needed.
To Monty: If the Plus/4 can't get an error string from the 1541 at power on, then it'll never load a file. One thing I thought of this morning is asking what device number your 1541 is set up as. DLOAD defaults to device 8, but even then PRINT DS$ should still get the disk status without needing to know what device number your drive is.
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Posted By
Monty
on 2005-10-04
08:05:15
| Re: Using Commodore 1541 disk drive on a Commodore + 4
you lost me now lol ...
On the plus/4 its reconizing the drive on boot up even without a disk in just not like it does when its connected to the c/64. Also PRINT DS$ on the c/64 works fine no porblems there whatsoever ...
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Posted By
Monty
on 2005-10-04
08:23:28
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Also Theres no faults at all on the plus 4 on any other ports ie the cassette deck loads fine scart and rf are fine joystick ports etc, I dont think theres anything wrong with the serial port either but I stilll dont really understand why it wouldnt work hmm ...
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Posted By
JamesC
on 2005-10-04
08:27:26
| Re: Using Commodore 1541 disk drive on a Commodore + 4
1) The Plus/4 does nto send any command to the 1541 upon power on. The lights on the 1541 coming on and going off, is due to programming within the 1541 and it will do this even with no computer connected.
2) The C64 does not have a PRINT DS$ command. DS$ is not a DOS variable in BASIC 2.0, but only available in BASIC 3.5 and higher (Plus/4, PET/CBM 4.0, 128 machines). PRINT DS$ on the C64 would only print a blank line, whereas on a BASIC 3.5 or higher you would see the DOS signature string (73, CBM DOS V2.6 1541, 00, 00). This is why I keep asking if you can get a response from the 1541, because if you don't get a valid DS$ on the Plus/4 then the 1541 isn't talking to it.
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Posted By
Monty
on 2005-10-04
08:35:29
| Re: Using Commodore 1541 disk drive on a Commodore + 4
when I do a PRINT DS$ on the plus/4 all it does is freeze so its not setup right somehow, what am I supposed to get back when I type this and press enter?
Im kinda running out of ideas now except for to wait for a plus/4 drive to turn up on ebay as they connect through the memory expansion port rather than the serial port ..
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Posted By
JamesC
on 2005-10-04
08:40:18
| Re: Using Commodore 1541 disk drive on a Commodore + 4
You should see the DOS signature string (73, CBM DOS V2.6 1541, 00, 00). Until you can get the 1541 to return this, attempts at loading a program will fail as the drive is not talking to the computer.
Are you 100% sure that the 1541-II acts exactly the same way?
I'm off to work, will be back in about 11 hours.... if anyone else wants to jump in here, feel free to do so.
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Posted By
Monty
on 2005-10-04
08:45:14
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Yeah the 1541 II acts the same way I just tested it again ..
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Posted By
Monty
on 2005-10-04
08:47:38
| Re: Using Commodore 1541 disk drive on a Commodore + 4
when i use the DLOAD"*" command, its says SEARCHING FOR 0:*
shouldnt it be, searching for 8:* 8 being the drives number or is that just for c/64?
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Posted By
Ulysses777
on 2005-10-04
09:17:37
| Re: Using Commodore 1541 disk drive on a Commodore + 4
One thing you can try...disconnect the drive from the Plus/4, then start up the Plus/4 and try PRINT DS$ to see if it produces a DEVICE NOT PRESENT ERROR. Just to see if there might be a fault with your Plus/4.
>when i use the DLOAD"*" command, its says SEARCHING FOR 0:*
shouldnt it be, searching for 8:* 8 being the drives number or is that just for c/64?
8 is the device number, 0 is the drive number. This is the same on all 8 bit Commodore machines. On the PET/CBM machines which use dual disk drive units, one drive would be 0, and the other 1, but both would be under device 8.
Which raises a question...is there a dual drive that can be connected to the Plus/4? (Does the 1541D actually exist?)
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Posted By
Monty
on 2005-10-04
09:54:10
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Relpy to >>
One thing you can try...disconnect the drive from the Plus/4, then start up the Plus/4 and try PRINT DS$ to see if it produces a DEVICE NOT PRESENT ERROR. Just to see if there might be a fault with your Plus/4. <<
Ok tried that and it threw up that error so the Plus/4 is ok ^_^
at least thats something so Im guessing its the drives now but how can that be if they both run fine on my C64?? hmm ..
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Posted By
Monty
on 2005-10-04
09:56:05
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Theres a 1541C on ebay whats that drive for ?
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Posted By
JamesC
on 2005-10-04
20:59:54
| Re: Using Commodore 1541 disk drive on a Commodore + 4
The 1541C is for a Commodore computer. 
It was meant to be paired with a 64C, but you can put it with any system that recognizes a 1541 (except yours, obviously).
As soon as I can find my technical documentation for the Plus/4 I'll see what would cause the serial bus not to respond. I think you either have a bad cable or a bad Plus/4 at this point.
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Posted By
JamesC
on 2005-10-04
22:58:41
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Ulysses, Commodore did not make a dual drive for the Plus/4 (or for the 64/128 either). MSD did make one that had both the IEEE and serial buses available, called the MSD SD-2. I have one here and it is a wonderful machine! User groups liked these because if you have the correct ROMs in the drive, you can make copies of disks without tying up a computer.
Rumor has it that Commodore didn't issue a dual drive because after the problems with the 1541's ROMs, they had too much trouble trying to reintroduce the dual drive code. It would have been easier to port over the code from a PET/CBM drive, except for the fact they would lose 1541 compatibility.
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Posted By
siz
on 2005-10-05
07:05:08
| Re: Using Commodore 1541 disk drive on a Commodore + 4
1541C: a slightly modified 1541 disk drive with bugfixed ROM and a track 0 sensor light barrier. This light barrier prevents the track 0 search noise.
The original problem: the 1541-II drive has the original ROM or something modified (ie JiffyDOS or something else)?
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Posted By
JamesC
on 2005-10-05
08:38:05
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Siz, there are several documented problems with the 1541 ROMs. Save with replace bug. Buffer allocation bug. Block-read and block-write commands (B-R and B-W). Block-Allocate sometimes allocates a whole track instead of one block. Reset command bug. (Source: Inside Commodore DOS, pages 206-208)
Also, many 1541Cs do not have the track 0 sensor functional as shipped from the factory; the user had to disassemble the drive and attach it. Commodore later removed it from the specifications altogether.
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Posted By
siz
on 2005-10-05
11:51:47
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Uhmm... I meant they fixed some bugs and introduced new ones. But the 1541C ROM is almost the same as the 1541-II one. (as I remember)
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Posted By
TLC
on 2005-10-14
17:59:21
| Re: Using Commodore 1541 disk drive on a Commodore + 4
Monty: You should find someone experienced enough to desolder and replace a chip on the motherboard. As it seems from the description and tests you gave/made, the Plus/4 (to be precise, the 7406 that is used to drive the serial bus) is broken.
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Posted By
TLC
on 2005-10-14
18:16:52
| Re: Using Commodore 1541 disk drive on a Commodore + 4
As for the dual drive question: nope, AFAIK there wasn't ever a dual drive for the Plus/4 (or the C64 whatsoever) . On the other hand: the "unit" (as a term) is in Commodore's terminology... There were dual drives in Commodore's profile, even if they weren't produced with serial bus. Still, the fact that the drives weren't produced with serial interface, and the Plus/4 wasn't equipped with IEEE-488 doesn't mean, that it could have been impossible to handle an IEEE-488 drive with the Plus/4... It's all a matter of some interfacing... You could, for example, get an IEEE-488 interface and hook a "big" dual Commodore drive (ie. a 8250) to the Plus/4, ...and then wonder, how you could access the second drive with the "regular" Basic commands, if the "unit" parameter wasn't handled by Basic 3.5  . ...Another point is, that Basic was also used in the higher profile Commodore machines (B256 and such ) that were shipped with IEEE-488 and were expected to handle dual drives pretty regularly... Commodore just probably didn't want to drop features from Basic 3.5 that have been implemented anyway.
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Posted By
JamesC
on 2005-10-14
21:23:34
| Re: Using Commodore 1541 disk drive on a Commodore + 4
TLCCNS:
a) Commodore did not market an IEEE interface for the Plus/4, yet they did with VIC/VC20 (VIC1111 if I remember correctly is the IEEE interface cartirdge). The VIC1111 will not fit in the Plus/4's cartridge slot.
2) By the time the Plus/4 came out, the PET/CBM series were pretty much finished anyway. Commodore was selling more 64's and 1541s to the home market than they did the entire PET/CBM series to business and educational markets. Therefore, there was no incentive to produce an IEEE interface for a disk drive that was shortly to be discontinued. Besides, the TCBM bus (theoretically) was just as fast if not faster than the IEEE bus.
iii) I have not attempted to use my MSD as the beginning of a chain of IEEE devices, then using its serial interface to connect the IEEE chain to the Plus/4. I doubt it would work, but I lack the IEEE drives and cables to even attempt such a test.
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Posted By
TLC
on 2005-10-15
12:45:40
| Re: Using Commodore 1541 disk drive on a Commodore + 4
JamesC:
a) Yep. They also marketed one for the C64 (for C64, there were also a couple of third-party IEEE-488 interfaces available). I don't know of any "official" (either CBM or third party) IEEE-488 cartridge for the Plus/4 either. (I know of a hacked -- or better said, ported -- one, which just shows that it was possible... just not really needed by anyone ).
2) So?...
iii) It would probably not work (or if it did, the OS of the MSD must be very clever).
The point isn't that it was actually done (or done regularly) ; the point was, that if there is a dual CBM drive, and it speaks CBM DOS, then it's given, how you can access drive0 and drive1. ...If they once implemented support for this CBM DOS feature in Basic, then there it was, even if they actually never produced a true serial or TCBM dual drive (that could be connected to the Plus/4 easily). ...They just didn't remove this feature from the Basic of the Plus/4. ...I guess.
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