SCSI terminator or a converter from HD50 to wide connector

Started by stt1, January 12, 2011, 08:06:36 AM

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stt1

January 12, 2011, 08:06:36 AM

I received two "junk" X68030 machines without HDDs. Neither there is a terminator in the end of cable. AFAIK, the SCSI cable should be terminated a way or another. Does these machines need termination as well?

If they do, then I have a problem - the scsi-cable connector in the HD-end in X68030 is the rare HD50 -type. Does someone have extra terminator out there? Or a adapter from HD50 to normal wider 50-pin connector? OR HD50-type hard drive?

netwalka

#1
January 13, 2011, 10:29:39 AM Last Edit: January 14, 2011, 10:35:22 AM by netwalka
Quote from: stt1 on January 12, 2011, 08:06:36 AM

I received two "junk" X68030 machines without HDDs. Neither there is a terminator in the end of cable. AFAIK, the SCSI cable should be terminated a way or another. Does these machines need termination as well?

If they do, then I have a problem - the scsi-cable connector in the HD-end in X68030 is the rare HD50 -type. Does someone have extra terminator out there? Or a adapter from HD50 to normal wider 50-pin connector? OR HD50-type hard drive?


http://cgi.ebay.com/Amphenol-HD50-Male-Centronics-50-Male-SCSI-II-Cable-/200316686024?pt=LH_DefaultDomain_0&hash=item2ea3ce0ec8

This kind of cable may help. The picture is not that clear, so I'm not sure that is a proper cable, but Amphenol-HD50 male connector is needed.

Once you find a proper connector, you may make a converter cable yourself, or get a matching terminator.

Soldering 50 lines of cable, quite a mass....=-D

There is a adaptor, too.  Amphenol-HD50 male TO HD50 female.  

Like below. I heard that could be found on YAJ.

stt1

#3
January 14, 2011, 10:28:12 AM
I'm sorry, seems that I'm failing here after all...  :(

Today I went through the junk boxes at workplace and (YAY!) found one HD50 terminator. No... it didn't fit. the connector was externally same size as in the mini-centronics on the rear panel, but it was then a way smaller than the internal scsi-connector.

What next? I'm starting to be quite sure that this is a laptop scsi-drive connector for 2,5" HDDs. I took some photos, what do you think?

The cable with colourful wires is taken from X68000 Super-HD (yes, SCSI on it) for comparison. Other is from the X68030



There are more photos in this folder, containing also the PCB-connectors (26-pin in Super-HD against 40-pin in X68030):

http://www.damage.fi/stt/X68030_SCSI/


After some googling I found out that issues have been with with connecting old laptop HDDs to SCSI-cable and there exists adapter(s) for doing this. However, this is opposite from what I would need - connecting the ribbon cable to normal size 50-pin terminator. So far I haven't found such adapter... Maybe I eventually need to build one or modify one of those opposite adapters.

And about soldering - soldering 50-pins is just boring, but doable  :)

netwalka

#4
January 14, 2011, 10:56:41 AM
Quote from: stt1 on January 12, 2011, 08:06:36 AM
Does these machines need termination as well?

I come to think about it.

Externally, termination is needed at the end of extenal device like HDD, MO.

How about internally. Is it needed?

I have seen some array resistor on the compact model's scsi sub-board. That might be working as a terminator.

How about x68030, any array resistor on the board? Maybe... on the bottom PCB? Or, IC style terminator.

x68000's inside is small and there's not much extra area. Even so, did they require you to install teminator yourself?



eidis

#5
January 15, 2011, 04:06:26 PM Last Edit: January 15, 2011, 04:10:55 PM by eidis
  Hi!

Sorry for the late reply. I think I might have a solution for your problem. Please take it with a grain of salt because I can not confirm that it will work. It should, but we all know how such things end up sometimes ;)

This SCSI connector guide could come in handy:
http://www.ramelectronics.net/scsi_connectors.ep

First you will need to convert internal IDC50 to HD68.

IDC50 Male to HD68 Male SCSI Adapter
http://cgi.ebay.com/NEW-SCSI-HPDB-68-Male-IDC-50-Male-Adapter-/330448415914?pt=LH_DefaultDomain_0&hash=item4cf042acaa

And now you can use an SCSI to IDE adapter. Here is a datasheet for Acard AEC-7720U and Acard AEC-7720UW:
http://dl.acard.com/manual/english/aec-7720u&uw.pdf

Both of them have integrated terminator. Acard AEC-7720U is confirmed as compatible with X68000. AEC-7720U has ID50 connector and AEC-7720UW has HD68. Until now no one has tested and confirmed AEC-7720UW as compatible with X68000. It could work.

Acard AEC-7720UW
http://cgi.ebay.com/Acard-AEC-7720UW-scsi-ide-bridge-FREE-SHIPPING-USA-/330518670690?pt=LH_DefaultDomain_0&hash=item4cf472ad62

Please post your results if you decide to go through with it.

Best of luck,
Eidis
X68000 personal computer is called, "X68K" or "no good good" is called, is the PC that are loved by many people today.

stt1

#6
January 20, 2011, 12:40:28 AM
Thanks for the answers... Let's see...

netwalka:

The scsi-subboard is quite similar (except connectors, of course) to Super-HD and has something which looks like resistor packs. I'm not sure though, if those affect only for external connections or also for internal.

eidis:

A really good idea, thanks, I believe I'll try having a HDD this way some day later. And yes, I know, this might not work, but it's as good guess as any of mine would be ;-)


Hmm... I think that I'll freeze this part of my project until I have changed the electrolytic capacitors to tantalum ones. If that alone fixes my X68030, then it's sure that it wont need any extra terminations internally. I let you know what happens...
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