GVP HD(8)+ and external CD.

[Liqourice]

Originally Posted by Kin Hell

11.88 is a bit low tbh....

Doesn't SCSI pull from 3.3V or am I mistaken??

I honestly don't know.

[idrougge]

Originally Posted by Kin Hell

11.88 is a bit low tbh....

No it’s not. 11,88 is within 1 % of 12,00.

Doesn't SCSI pull from 3.3V or am I mistaken??

There is no 3,3 V source in a SCSI system.

[thebajaguy]

The SCSI Sense error is from an electrically unstable SCSI bus, and termination is normally the culprit. The two most distant points on the SCSI bus must be terminated.

GVP HD8+ controller should have termination on it (native), or the HD inside the unit (but not both). Normally the drive doesn't (removed) and the controller does (soldered in). The external connector is a DB25, like Apple used in that era. One must use a proper, (thick) shielded, DB 25 SCSI cable (which is internally a 50-conductor cable, each signal line is twisted with a ground) to the next device you have. You can not use common Parallel-style cables, as they lack the needed twisted-ground lines with signal, and lack external grounded shielding in the overall cable.

The new device needs external power, and the device (if no others to be connected), needs it's termination on. If you use drive termination, no external termination module gets used on the daisy-chain port (if equipped). If an external termination device is used, the external device must supply term power as the GVP unit does not supply anything to the SCSI bus TrmPwr line (the diode and fuse are not installed).

The original GVP internal disk is normally at SCSI 0, and the controller is native 7. Your new device must have a unique SCSI ID from 1-6 in this case. You set the I jumpers for this (1/2/4 - binary add math to get your wanted SCSI ID).

You do not need a new ROM. You do not need to reseat any ROM. You do not need a recap. The A500/GVP HD8 PSUs should be fine if your new device has it's own PSU.

The hardware in the GVP (and most legacy Amiga SCSI HW) is 5V Single Ended (SE) SCSI, and runs on 5V technology. If your external device is wide SCSI (68-pin) or Hot-Plug (80), then things get a bit more complex, but the device >must< support SE mode to be compatible. Many are marked SE/LVD, some are auto-detect, and some have a jumper to force SE.

A note that you must terminate the upper bus pins of any 68/80-pin SCSI device as they are native 16-bit Wide SCSI devices, and the not-connected signals are not allowed to float. Many have 8-bit SE/5V compatibility, so they can work, but this still makes cabling/terminating them, and adapting them down to 50-pin 8-bit SCSI a bit of a challenge. I usually would run a 68-pin device with a cable termination module (active), let the external unit supply TrmPwr, and then adapt down from 68 to 50 to the cable that comes from the Amiga SCSI interface.

[levo-ace]

Do you have more than one internal drive ?
And is the cable to the internal drive ( if you only have one ) very short ( <7cm ) ?

The reason I ask is that SCSI only uses a terminator on either end of the cable . The internal drive does not count if it is fitted to the card with a very short cable .
AMIGA hard cards tend to forget this and they always solder the terminators on the card , but if you have internal AND external drives then this termination is not needed .

Another thing to note is that the HC+8 does NOT provide term power , one of the devices in the chain needs to do this .

One last thing , the 3v being mentioned everywhere is due to the scsi termination +5v-220R-signal-330R-0v . This gives approx 3v on the signal line .

[Kin Hell]

Originally Posted by levo-ace

<snip>

One last thing , the 3v being mentioned everywhere is due to the scsi termination +5v-220R-signal-330R-0v . This gives approx 3v on the signal line .

Indeed!

As jope mentioned earlier, throw the HD on the card & it should just work.

@ Liqourice

No luck yet then?

[Liqourice]

Originally Posted by thebajaguy

The SCSI Sense error is from an electrically unstable SCSI bus, and termination is normally the culprit. The two most distant points on the SCSI bus must be terminated.

GVP HD8+ controller should have termination on it (native), or the HD inside the unit (but not both). Normally the drive doesn't (removed) and the controller does (soldered in). The external connector is a DB25, like Apple used in that era. One must use a proper, (thick) shielded, DB 25 SCSI cable (which is internally a 50-conductor cable, each signal line is twisted with a ground) to the next device you have. You can not use common Parallel-style cables, as they lack the needed twisted-ground lines with signal, and lack external grounded shielding in the overall cable.

The new device needs external power, and the device (if no others to be connected), needs it's termination on. If you use drive termination, no external termination module gets used on the daisy-chain port (if equipped). If an external termination device is used, the external device must supply term power as the GVP unit does not supply anything to the SCSI bus TrmPwr line (the diode and fuse are not installed).

The original GVP internal disk is normally at SCSI 0, and the controller is native 7. Your new device must have a unique SCSI ID from 1-6 in this case. You set the I jumpers for this (1/2/4 - binary add math to get your wanted SCSI ID).

You do not need a new ROM. You do not need to reseat any ROM. You do not need a recap. The A500/GVP HD8 PSUs should be fine if your new device has it's own PSU.

The hardware in the GVP (and most legacy Amiga SCSI HW) is 5V Single Ended (SE) SCSI, and runs on 5V technology. If your external device is wide SCSI (68-pin) or Hot-Plug (80), then things get a bit more complex, but the device >must< support SE mode to be compatible. Many are marked SE/LVD, some are auto-detect, and some have a jumper to force SE.

A note that you must terminate the upper bus pins of any 68/80-pin SCSI device as they are native 16-bit Wide SCSI devices, and the not-connected signals are not allowed to float. Many have 8-bit SE/5V compatibility, so they can work, but this still makes cabling/terminating them, and adapting them down to 50-pin 8-bit SCSI a bit of a challenge. I usually would run a 68-pin device with a cable termination module (active), let the external unit supply TrmPwr, and then adapt down from 68 to 50 to the cable that comes from the Amiga SCSI interface.

As it is right now it's not working. It's not the drive because it works just fine when I connect it to a PC with SCSI. So, something has happened to the GVP controller since it worked for close to 30 years without any issue. That's why I'm talking about perhaps the ROM has gotten damaged in some way, or whatever. It is not a termination issue because if that were true it would never have worked.

I've had to remove the 30 pin sims that were on it because it fails miserably with any of them in. I doubt all 4 sims have gone bad, I get a fail from the board whichever sticks I put in and configure the board in accordance.

These things need to be resolved before I even attempt to connect an external CD-rom. This is why I'm talking about replacing the ROM, not that I think that will magically make the CD work, I want to fix the issues with the board and that's the one thing that's easy to try. It may have gotten damaged when I screwed up my 3.1 kickstart (the soldering for Rev 5 boards) because it was connected when I turned it on and my 500 went black.

[Liqourice]

Originally Posted by Kin Hell

Indeed!

As jope mentioned earlier, throw the HD on the card & it should just work.

@ Liqourice

No luck yet then?

No, I haven't done anything with the GVP because I don't have the knowledge and equipment to find out what's wrong with it. Not gotten hold of a ROM to replace either but I will as soon as I can get the correct type of eprom chip. A bit short on funds right now so it will have to wait.

[Liqourice]

Originally Posted by levo-ace

Do you have more than one internal drive ?
And is the cable to the internal drive ( if you only have one ) very short ( <7cm ) ?

The reason I ask is that SCSI only uses a terminator on either end of the cable . The internal drive does not count if it is fitted to the card with a very short cable .
AMIGA hard cards tend to forget this and they always solder the terminators on the card , but if you have internal AND external drives then this termination is not needed .

Another thing to note is that the HC+8 does NOT provide term power , one of the devices in the chain needs to do this .

One last thing , the 3v being mentioned everywhere is due to the scsi termination +5v-220R-signal-330R-0v . This gives approx 3v on the signal line .

It is as it was when I bought it in 1992. Same single drive (Quantum LPS 120MB), same very short cable. Only difference is I've removed the sims because it won't do anything with them in.

[levo-ace]

have you set the memory jumpers , so that it realises that there is no ram on board ?

[Liqourice]

Originally Posted by levo-ace

have you set the memory jumpers , so that it realises that there is no ram on board ?

Yes, as mentioned I've configured it according to what's mounted, or not.