Thinnet to UTP transitioner

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gerryk

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Oct 10, 2011, 11:11:34 AM10/10/11
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I just got my hands on a MicroVAX, but as it dates from the 80's has a
thin ethernet connection.
Wondering if anyone has 10Base-2 to 10Base-T transitioner, or switch
with each type of connector? I used to have one, but it has long since
been lost.
I will demonstrate great gratitude to anyone who has such an esoteric
piece of kit thay they would part with.

Duncan Thomas

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Oct 10, 2011, 1:06:31 PM10/10/11
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I might be able to magic up such a beast when I next head home if
you're not sorted by then... I'll ask around work too, there used to
be enough of the damn things in this place.

--
Duncan Thomas

Donal O'Domhnaill

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Oct 11, 2011, 3:08:50 AM10/11/11
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A MicroVAX!!!!!!!!!

Where did you get a MicroVAX from? What model is it if you do not mind my asking? Is it up in the labs? It is not fairly huge?

Donal
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gerryk

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Oct 11, 2011, 4:02:21 AM10/11/11
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Yup. It's a uV 3100, model MV-31FDTA-A. It has a CVAX+ processor at (I
think) 12MHz, 4MB on the motherboard and what looks like an additional
12MB expansion board. It also has SCSI card and an RZ26 HDD, which I
think is 1.05GB.
Physically, it's quite small, compared to what you would imagine a VAX
would be. Basically it's desktop form factor, but would outperform a
VAX 11/780 about 4:1, and a MicroVAX II about 2:1. I had a look inside
and the copyright notices are dated 1989.
I have a bunch of pics that I will post later.

gerryk

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Oct 12, 2011, 6:02:45 AM10/12/11
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It has an AUI port, so it occurs to me that a 10Base-T transciever
might work too.
Don't suppose there's one knocking around? Thankfully, they are much
more readily available that media converters, and a damn sight
cheaper.
The console port has a daft offset clip thing, so I can't just use
RJ12. Might just solder a DB9 to the motherboard.

gerryk

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Oct 12, 2011, 6:39:10 AM10/12/11
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Some pics.... http://imgur.com/a/eSkKH

Domhnall Walsh

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Oct 12, 2011, 7:25:42 AM10/12/11
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Wow, last time I saw one of those the year still started with "19". Nice bit of nostalgia there. Pity I don't have any AUI transceivers.

gerryk

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Nov 8, 2011, 11:54:50 AM11/8/11
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Ok, so I made up a console cable, and got a successful boot... or partly successful anyhow, as it boots to console mode, but can't see the SCSI drive.

A few diagnostics...

The output of SHOW DEV is...
http://imgur.com/Ug5ju

and TEST 50 is...
http://imgur.com/VuFEn

Basically it's saying that it can only see the ethernet device, the clock battery is dead, the clock and NVRAM need to be reset, and that the ethernet device is unterminated. Since it can't see the SCSI drive either, the ethernet exception has ?? which is basically fatal, so...

I have ordered a 3.6v NiCd, which will work for the clock/NVRAM.
I have ordered an AUI to 10base-t media convertor.
But it looks like I also need a SCSI terminator... or possibly 2, which, hopefully is why the drive isn't being seen.

Anyone got a couple of terminators lying around... even just to test. Since this is a DEC box, I am reluctant to splash out on stuff that may or may not work, due to the disregard of standards back in the 80s. If it works, I'll buy some, if necessary.

Nice to have some progress, though...

Gerry
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Duncan Thomas

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Nov 8, 2011, 12:21:44 PM11/8/11
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What connector do you need on the terminators? There were at least three in use in that era.

A colleague also has a VMS reference manual I can drop under the scanner if that is of use?

gerryk

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Nov 8, 2011, 12:53:13 PM11/8/11
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The external is centronics, the internal is the old 50 pin... looks like an IDE connector.

Domhnall Walsh

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Nov 8, 2011, 1:02:31 PM11/8/11
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So it's SCSI 1 then. Crap, don't have anything that old, sorry, but they're gettable off eBay for about 8 euro delivered if that helps?

Domhnall.

gerryk

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Nov 8, 2011, 1:04:19 PM11/8/11
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Bring somewhat of a cheapskate, I'd like some surety that they'd work first.

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