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From: addison@pollux.usc.edu (Richard Addison)
Newsgroups: comp.sys.amiga,comp.sys.amiga.tech
Subject: Re: Bizarre problem with Mitsubishi multisync monitor
Summary: Your machine thinks you have a GenLock
Message-ID: <19831@usc.edu>
Date: 12 Sep 89 04:10:08 GMT
References: <11574@boulder.Colorado.EDU>
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Reply-To: addison@pollux.usc.edu (Richard Addison)
Followup-To: comp.sys.amiga
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Organization: University of Southern California, Los Angeles, CA
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In article <11574@boulder.Colorado.EDU> hunt@tramp.Colorado.EDU (Lee Cameron Hunt) writes:
>
>I just received a Mitsubishi Dimond Scan multisync monitor (AUM-1381A) and
>it doesn't work too well with my Amiga 2000.  I have a stock 2000 with a
>HardFrame 2000 SCSI board.  The machine will not boot or reboot with the
>monitor cable plugged in.  Actually, the machine will not boot when the
>R, G, B, Hsync, or Vsync lines are connected (the ground lines don't
>matter).  But, if I boot or reboot with the aformentioned lines disconnected
>and then connect then, things work fine.
>
>Very strange.
>
>Any suggestions.
>
>--Lee
>(...!ncar!boulder!spot!hunt)

You need to buffer the Sync lines.  From what I can tell, the AUM-1381A
loads the Sync lines enough that the custom chips think that you are
trying to drive a sync signal into the machine (as a GenLock would).

The Diamond Scan is flexible enough that you can use either inverting
or non-inverting buffers.  I believe I used some flavor of the ever
popular 7404 Hex Inverter (which are great for getter rid of curses
of all sorts :-).

BTW, apparently the A1000 doesn't need to be buffered when it is
connected to the Diamond Scan.

If you need details, send email and I'll look at my cable again.

Richard Addison
"Klein bottles for sale.  Inquire within."