The GVP 1208 doesn't have a realtime clock. When you use a Reatime clock module and put an card for example a Blizzard 1230 IV, then the Realtime clock module will be active.
If you have a real time clock on your card, then it is best to remove the Realtime clock module.
I also have this memory expansion GVP 1208 with SCSI. I connected the external CD-ROM and use an active SCSI terminator.
Most CD-ROM has a inactive teminator when you put the jumper on it, then you should get your CD-ROM working.
The only problem with this SCSI controller is, you need always put a CD in your CD-ROM and turn it on. Or you need to wait for 30 seconds to boot your A1200.
