[comp.sys.amiga] Bizarre problem with Mitsubishi multisync monitor

hunt@tramp.Colorado.EDU (Lee Cameron Hunt) (09/12/89)

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)

addison@pollux.usc.edu (Richard Addison) (09/12/89)

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."

jenglish@tardis.Tymnet.COM (Jim English) (09/13/89)

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
>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.

I ran into this same problem hooking up my Samsung Multisync. Simply use the 
Composite Sync output from the 2000, and hook both the monitors Hsync, and
Vsync to it. Works like a champ.
-- 
Jim English    MD-IPC   | JENGLISH@F74.TYMNET.COM or jenglish@tardis.tymnet.com
(214)637-7406  Dallas   | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jenglish

addison@pollux.usc.edu (Richard Addison) (09/18/89)

In article <583@tardis.Tymnet.COM> jenglish@tardis.Tymnet.COM (Jim English) writes:
}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
}}HardFrame 2000 SCSI board.  The machine will not boot or reboot with the
}}monitor cable plugged in.  [...]  But, if I boot or reboot with the
}}aformentioned lines disconnected and then connect then, things work fine.
}
}I ran into this same problem hooking up my Samsung Multisync. Simply use the 
}Composite Sync output from the 2000, and hook both the monitors Hsync, and
}Vsync to it. Works like a champ.

I tried using the Composite Sync from the 2000 when I first got my Mitsubishi
Diamond Scan but I found that the video signal appeared blurry.  The display
looks much sharper when I use buffers on the separate sync signals.  Your
mileage may vary.

Richard Addison
"Waste is a terrible thing to mind."