I have a Mac Plus with a pretty unusual MegaScreen conversion that I'd
like to revive. The Mac itself works fine off an exteranl SCSI drive
with OS7, but the internal 800k floppy drive is dead. I tried
cleaning it, but it still won't read any disks. I have about 3 or 4
working Sony 2Mb floppies culled from Mac Classics and LCII's. If I
take one of those drives and put it in in place of the 800k, will it
work as an 800k drive? I am not lazy :-), its just that because of
the Megascreen conversion, taking that Plus apart is a real pain in
the ass, so I though I'd ask, rather than take it apart, put it back
together, and then have to do it all over again because it does not
work.
Thanks in advance for any info!!

PS Anyone know what Megascreen is supposed to do? It has a 9 pin DIN
female connector coming out of it, which I assume goes to an external
monitor. I have not been able to find any info on it online. Does it
require an extension to work, or will the Monitors CP in OS7.5.5 do
the trick?

Hi Ripley59,

> I have a Mac Plus ... but the internal 800k floppy drive is dead ...
> I have about 3 or 4 working Sony 2Mb floppies ... If I take one ...
> and put it in in place of the 800k, will it work as an 800k drive?

From memory - no ... the higher capacity (once frmatted 1.4 MB) drives
require an upgrade of the floppy controller chip on the motherboard.

Again, from memory, Apple used to sell a kit to do the jobbie. I think
your easiest shot is to find a deceased Mac Plus or SE with a working 800k
drive.

Original Mac (128 & 512k) - 400Mb Single sided, single density ...
Mac Plus/SE - 800Mb - Double sided, double density
Later SE/Classic & Beyond - 1.4MB - Double sided - High density

Good luck!

Mikey Mike

Hi Ripley59,

> I have a Mac Plus ... but the internal 800k floppy drive is dead ...
> I have about 3 or 4 working Sony 2Mb floppies ... If I take one ...
> and put it in in place of the 800k, will it work as an 800k drive?

From memory - no ... the higher capacity (once frmatted 1.4 MB) drives
require an upgrade of the floppy controller chip on the motherboard.

Again, from memory, Apple used to sell a kit to do the jobbie. I think
your easiest shot is to find a deceased Mac Plus or SE with a working 800k
drive.

Original Mac (128 & 512k) - 400Mb Single sided, single density ...
Mac Plus/SE - 800Mb - Double sided, double density
Later SE/Classic & Beyond - 1.4MB - Double sided - High density

Good luck!

Mikey Mike

Ripley59 <ripley59@earthlink.net> writes:
>
> I have a Mac Plus with a pretty unusual MegaScreen conversion that I'd
> like to revive. The Mac itself works fine off an exteranl SCSI drive
> with OS7, but the internal 800k floppy drive is dead. I tried
> cleaning it, but it still won't read any disks. I have about 3 or 4
> working Sony 2Mb floppies culled from Mac Classics and LCII's. If I
> take one of those drives and put it in in place of the 800k, will it
> work as an 800k drive? I am not lazy :-), its just that because of
> the Megascreen conversion, taking that Plus apart is a real pain in
> the ass, so I though I'd ask, rather than take it apart, put it back
> together, and then have to do it all over again because it does not
> work.

If you install a 1.44M drive in a Mac without the ROMs for it, the
drive will be seen as an 800K drive. It should be able to read and
write 800K media just fine, although I'm not sure how much I'd trust
the reliability of the media. I've personal experience with this on
Mac SE's. I would expect the same behavior from a Plus.

Unfortunately, you can't get 1.44M-compatible ROMs for a Plus. You can
get them for an SE. It might be worth looking for an old SE-FDHD on
eBay if you're interested in actually using a Mac this old.

> PS Anyone know what Megascreen is supposed to do? It has a 9 pin DIN
> female connector coming out of it, which I assume goes to an external
> monitor. I have not been able to find any info on it online. Does it
> require an extension to work, or will the Monitors CP in OS7.5.5 do
> the trick?

Can't help with this part.

-- David

Ripley59 <ripley59@earthlink.net> writes:
>
> I have a Mac Plus with a pretty unusual MegaScreen conversion that I'd
> like to revive. The Mac itself works fine off an exteranl SCSI drive
> with OS7, but the internal 800k floppy drive is dead. I tried
> cleaning it, but it still won't read any disks. I have about 3 or 4
> working Sony 2Mb floppies culled from Mac Classics and LCII's. If I
> take one of those drives and put it in in place of the 800k, will it
> work as an 800k drive? I am not lazy :-), its just that because of
> the Megascreen conversion, taking that Plus apart is a real pain in
> the ass, so I though I'd ask, rather than take it apart, put it back
> together, and then have to do it all over again because it does not
> work.

If you install a 1.44M drive in a Mac without the ROMs for it, the
drive will be seen as an 800K drive. It should be able to read and
write 800K media just fine, although I'm not sure how much I'd trust
the reliability of the media. I've personal experience with this on
Mac SE's. I would expect the same behavior from a Plus.

Unfortunately, you can't get 1.44M-compatible ROMs for a Plus. You can
get them for an SE. It might be worth looking for an old SE-FDHD on
eBay if you're interested in actually using a Mac this old.

> PS Anyone know what Megascreen is supposed to do? It has a 9 pin DIN
> female connector coming out of it, which I assume goes to an external
> monitor. I have not been able to find any info on it online. Does it
> require an extension to work, or will the Monitors CP in OS7.5.5 do
> the trick?

Can't help with this part.

-- David

they.are@it.again.com (Mikey Mike) writes:
>>
>> I have a Mac Plus ... but the internal 800k floppy drive is dead ...
>> I have about 3 or 4 working Sony 2Mb floppies ... If I take one ...
>> and put it in in place of the 800k, will it work as an 800k drive?
>
> From memory - no ... the higher capacity (once frmatted 1.4 MB) drives
> require an upgrade of the floppy controller chip on the motherboard.

The ROMs are necessary to use 1.44M media. Without the ROMs, the drive
should still be able to read/write/format 800K media.

-- David

they.are@it.again.com (Mikey Mike) writes:
>>
>> I have a Mac Plus ... but the internal 800k floppy drive is dead ...
>> I have about 3 or 4 working Sony 2Mb floppies ... If I take one ...
>> and put it in in place of the 800k, will it work as an 800k drive?
>
> From memory - no ... the higher capacity (once frmatted 1.4 MB) drives
> require an upgrade of the floppy controller chip on the motherboard.

The ROMs are necessary to use 1.44M media. Without the ROMs, the drive
should still be able to read/write/format 800K media.

-- David