68 pin SCSI in Amiga

[BLTCON0]

@LoadWB
Yes indeed, back in the day (when I was all about SCSI) they were about 3x the price of regular ones, so indeed they aren't 'expensive' but just 'more expensive'.
I actually corrected it right away but you posted faster than your shadow :-)

Furthermore, as today SCSI is mostly gone, I guess they can occasionally be found dirt-cheap as stock surplus or whatever - the culprit (most often) being with the seller unable to distinguish between passive and terminated ones.

[zipper]

Seagate wide drives were a distinguished exception - they universally worked fine in narrow mode, without requiring bias-voltage.

Yes, my 68pin SG had built in termination available so I could use it on the other end in my CSPPC SCSI cable as terminator, the other end needed an active terminator.

[LoadWB]

@LoadWB
Yes indeed, back in the day (when I was all about SCSI) they were about 3x the price of regular ones, so indeed they aren't 'expensive' but just 'more expensive'.
I actually corrected it right away but you posted faster than your shadow :-)

Furthermore, as today SCSI is mostly gone, I guess they can occasionally be found dirt-cheap as stock surplus or whatever - the culprit (most often) being with the seller unable to distinguish between passive and terminated ones.

Right, these adapters and bloody S-Video to composite adapters, as well.  Flushed $20 on 10 of them only to find they're completely wire-through.  (That's a whole other thread and topic, though.)

If you want a good laugh, and some reputable outlets are guilty of this shyt, too, go look up things like USB-to-Firewire or HDMI-to-component adapters.  Read the small print and you'll find these are completely wired-through, not a circuit in the mix to do any actual conversion.

Back on topic, yes, I found that both Segate and IBM LVD-SCSI drives are great in whatever system you throw them in.  Most of the time even if you don't set the jumper for SE they'll still work just fine.  That's a big bonus for those who don't know any better (hey, we all start somewhere!) and those who just start over-looking simple things (hey, we all end up somewhere!)

[BLTCON0]

@LoadWB
Very true. Which brings forward a terminology issue/dilemma, too.

My preferred usage would be "adapter" when only the connector's physical format is changed, but the physical (electrical) protocol/signalling remains mostly unchanged (mild alterations such as voltage level conversion wouldn't the "adapter" concept).
Otherwise it would be "converter".

If such a clear distinction was universally adopted and followed, there would be no confusion.

For example, if someone sold a USB-to-PS2 *adapter*, it would be implied that it's just wire-through and the protocol conversion (or selection) is deferred to the device (e.g. a keyboard or mouse in this case).
Same for S-Video to Composite, HDMI-to-VGA etc adapters (where a subset of the S-video / HDMI connector pins must alter -if supported by the graphics hardware- their protocol/signalling significance at the root level, so only a passive wire-through "adapter" is then needed).

If on the other hand it was sold as a USB-to-PS2 *converter* it would be implied it's an active device meant to convert from a specific protocol into another specific protocol.

But as nothing is explicitly set in stone, the terms are more often than not interchangeable and confusion prevails.

[RiP]

Well, the adapter didn't work with Adaptec SCSI card too:
https://www.amazon.com/Monoprice-100077-SCSI-HPDB-Adapter/dp/B001TIQ8G2

I'll try to find this next time:
https://www.aliexpress.com/item/SCSI-SCA-80-Pin-To-SCSI-68-Pin-IDC-50-Pin-Adapter-SCSI-80-68-50/293779398.html

[Chucky]

Thanks, I thought it should be OK , but I never heard of an Amiga user doing it.
Len

CSPPC??  I use Wide scsi on my A4000.
sure using a -> IDE adapter and SSD disk    but stll wide (68pin)

31MB/sec:)

[BLTCON0]

Well, the adapter didn't work with Adaptec SCSI card too:
https://www.amazon.com/Monoprice-100077-SCSI-HPDB-Adapter/dp/B001TIQ8G2

That's a passive adapter. No good for your case as I already wrote.

I'll try to find this next time:
https://www.aliexpress.com/item/SCSI-SCA-80-Pin-To-SCSI-68-Pin-IDC-50-Pin-Adapter-SCSI-80-68-50/293779398.html

Why would you do that? You said your drive is an 68-pin one, not an SCA 80-pin one. Even if you had a SCA drive, the story wouldn't end with this adapter.

For your setup, ideally you should desolder the onboard passive terminator of the GVP card and use dedicated 50-pin *active* terminators at both ends of the cable. It should look like this:

{IDC1}Term1-----{IDC2}GVP 50pin-----......--------{IDC3}[high-byte adapter + your LVD drive]----{IDC4}Term2

- Term1, Term2 are something like this.
- The high-byte terminating adapter is something like this.
-So you need a cable with 4 50-pin IDC (female) connectors.
IDC1 is where Term1 gets plugged.
IDC2 connects to GVP's onboard 50-pin header
IDC3 connects to the 50-pin outlet of the 50-68 high-byte adapter (the 68-pin outlet connects to your LVD SCSI drive itself, the drive must have TP enabled and must be set for SE mode)
IDC4 is where Term2 gets plugged
-Cable segment between IDC1 and IDC2 must be short, the same for IDC3 to IDC4 (about 5 cm). IDC2 to IDC3 length doesn't matter much (well, it still shouldn't exceed 1.5m)
Good custom cables here.

Remember to set TP (this will provide the necessary power for the standalone active terminators Term1 and Term2) and to force SE just in case the drive doesn't autoconfigure itself in SE mode.

If you decide to skip desoldering the onboard passive terminator of the GVP card, then you only need your cable to match the IDC2-IDC3-IDC4 configuration, and of course you skip using Term1. I'm not actually advising against this configuration, it should still work OK.

That's about it.

[RiP]

If you decide to skip desoldering the onboard passive terminator of the GVP card, then you only need your cable to match the IDC2-IDC3-IDC4 configuration, and of course you skip using Term1. I'm not actually advising against this configuration, it should still work OK.

That's about it.

Well, my 68pin SCSI hard disk doesn't have TE but TP.
Then I tried this configuration but GVP/Adaptec didn't detect the 68pin SCSI hard disk:

{IDC1}GVP 50pin-----{IDC2}[high-byte adapter+my LVD drive]----{IDC3}50pin SCSI 4GB HDD+TE jumper enabled (I used it since I didn't have 50pin Termination)