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From: wilner@motcid.UUCP (Corey S. Wilner)
Newsgroups: comp.sys.apple2
Subject: DRAM speed on extended 80-col board
Message-ID: <4513@mint17.UUCP>
Date: 7 May 91 15:59:16 GMT
Organization: Motorola Inc., Cellular Infrastructure Div., Arlington Heights, IL
Lines: 28

I have come across a problem with my extended 80-column board
and double-hi-res graphics.  It don't work!!!  I connect the
jumper between pins 50 and 55 on the card but the system goes
haywire (some of the time) when DHR mode is entered (as far as
I can tell).  Even when DHR seems to be working, not everything
appears on the screen correctly.  This could be the monitor (I
have a Monitor ///, I think, it's what was sold with the units
back in 1983) but that doesn't tell me why the computer screws up.
I have a revision B motherboard so
I don't think that is the problem (the manual mentions that DHR
can't be used on Rev. A boards.).

Since this is not an Apple product (I got it from a friend in
Korea a few years back), I am not sure it was built with the
proper speed DRAMS.  They are 150ns types.  This is the only
thing I can think of that would screw up DHR.  The board works
perfectly otherwise (RAMDISK, Appleworks, etc.) without the jumper
being in.

Any answers??

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Corey S. Wilner    |                            |   __o
Motorola Cellular  | ..!uunet!motcid!wilner     |  -\<,
708-632-7206       | motcid!wilner@uunet.UU.NET |  O/ O
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The three most dangerous things in the world are a hardware type with a
program patch, a programmer with a soldering iron, and a user with an idea.