My GVP A2000-HC+8 doesn't detect Hitachi 73GB SCSI 68pin
I used SCSI 68 Male to IDC 50 Male Adapter. I enabled TP/Force SE but they didn't help.
Since it has a "force SE" jumper (force Single-Ended mode) it means it's an LVD (low voltage differential) drive.
These drives never have onboard termination. The "termination power" jumper is just to provide power to a standalone terminator, plugged at the end of the cable.
This also brings another implication into play:
Wide-SCSI bus (= 68 pin = 16 bit) is conceived as an extension to the older narrow-SCSI bus (=50 pin = 8 bit) standard. Actually, commands are still transferred in 8-bit 5 MHz async mode, regardless of advertised bus speed. The wide transfers (16 bit) or faster transfers (10 mhz Fast, 20 Mhz Ultra) are purely for data transfers.
So a 16-bit bus is more or less an 8 + 8 bit bus, with a low-byte (corresponding to operation in 50 pin narrow SCSI mode) and a high-byte (used in 68-pin wide SCSI mode).
Most 68-pin drives do require the presence of so-called bias-voltage on ALL the scsi lines (both low byte and high byte ones) in order to successfully init. This means that when in narrow mode, they require a special 50-68 adapter with high-byte active termination, which (as a side effect) will provide said bias voltage (assuming Termination Power exists, of course, but this can be set).
Alternatively, in lack of such an adapter, one can place the 68-pin drive with a simple (passive) 68-50 adapter LAST in the chain and enable its onboard terminator, which will have an identical side-effect.
Unfortunately, LVD drives by design don't have onboard termination, so this trick can't be used in your case. Using a wide active external terminator will not have the desired effect. Your safest bet is a (more expensive) high-byte terminated 68-50 adapter, plus (of course) active 50-pin terminators at both ends of the controller's 8-bit bus, with the drive (again of course) in SE mode.
Seagate wide drives were a distinguished exception - they universally worked fine in narrow mode, without requiring bias-voltage.