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Emax SCSI : The Plus Model
Overview
One of the last upgrades to the Emax was to provide an external SCSI connector so that external SCSI hard and removable drives could be connected to the Emax. This upgrade followed on from the internal SCSI capability that was added for an internal hard disk, as contained within the HD models.
Production keyboard and rack models came out the factory with this capability in 1989, and were denoted as Plus models. The upgrade could also be retrofitted to later (but NOT earlier) Emax keyboard and rack models.
Why do I need external SCSI ? You can save and load samples to a ZIP100 drive, and you can get expand you library of samples by buying ZIP100 cartridges full of 36 new OMI sample banks from us!
Can I upgrade my Emax with external SCSI? First you need to know which digital board you have, the revision and part numbers are printed on the board in white.
- Revision 1 Part Number 320 - IMPOSSIBLE TO UPGRADE
- Revison 2 Part Number 320 - POSSIBLE TO UPGRADE
- Revison 3 Part Number - POSSIBLE TO UPGRADE
Next you need to check whether you already have SCSI installed. Look on the digital board for all
of these:
- A 5380 SCSI chip at IC6
- The 28-pin Plus OS boot ROM labelled IP355 at IC13
- The HD or Plus TIM PAL at IC49 (IP356 or IP379)
If you have these parts fitted its a simple matter to extend the SCSI cabling to provide an
external connector, and a simple OS modification to provide selection of the SCSI ID. Unfortunately the OS was NOT modified to format or read/write a larger disk space than 20 MB. Even a maximum of 100 banks at 512kb would have been nice,
at 50 MB !
Upgrade Kit If you don't have these chips fitted, you can buy an upgrade kit with these components from us:
- One 5380 SCSI chip
- One Emax Plus Boot ROM
- One Emax Plus TIM PAL
- An external SCSI adapter connector
- The OS Plus software on diskette
- A hard copy of the E-mu Systems install instructions
Read the instructions opposite first as you'll need a service tech to install the upgrade if you
have a Rev 2 board. Rev 1 digital boards can not be upgraded as there is no space on the board for the SCSI controller.
OS Plus Feature
The Plus OS has only one additional feature - the ability to select a SCSI id. Press and hold the Transpose key, the display will show:
TRANSPOSE:
SCSI ID: 0
Press the numeric key which matches the SCSI id of the drive you want to access, and if this drives is active on
the SCSI bus it will be used as the Emax active drive.
External ZIP 100 Drive Whilst the Emax predates the Iomega Zip 100 drive by nearly 10 years, it still works a treat! Connect the standard Zip 100 drive to the Emax Plus
using a 25 - 25 pin SCSI cable. Select the drive ID (as above) and format and read/write as usual.
 Internal ZIP 100 Drive An even cooler upgrade is to fit an internal SCSI Zip 100 to replace the floppy drive in a HD or Plus model. This means replacing or supplementing the internal hard disk. You will need to
rig up both the ZIP drive and the floppy, so you can copy all your sample library onto ZIP disks first. The PSU may not be able to cope with both a hard drive and ZIP drive, as the ZIP requires 0.3
A more than the floppy drive. The hard disk is noisy anway so best use just the internal ZIP, and set the ZIP SCSI ID to 0, then the Emax will boot from ZIP.
Technical The SCSI upgrade is based round the NCR5380 SCSI-1
controller chip which was developed by NCR in 1984. It gained immediate use in the Apple Mac, thanks to it being the first low cost SCSI controller chip. It runs the SCSI bus at 1.5 MB per second. |
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Instructions
