Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!microsoft!brianw
From: brianw@microsoft.UUCP (Brian WILLOUGHBY)
Newsgroups: comp.sys.apple
Subject: Western Design Center (was Re: 6V power)
Message-ID: <10045@microsoft.UUCP>
Date: 22 Dec 89 02:51:31 GMT
References: <8524.infoapple.net@pro-generic>
Reply-To: brianw@microsoft.UUCP (Brian WILLOUGHBY)
Organization: Microsoft Corp., Redmond WA
Lines: 36

sb@pro-generic.cts.com (Stephen Brown) writes:
>You favour getting the 65816's 6 volts from a resistive divider? This assumes
>that the current it draws is the same for all operations, and I don't know if
>this is safe to say.  As the current drawn by the '816 changes, so will its
>supply voltage, unless the resistive divider is very robust (in terms of
>current) indeed.

Whoever still clings to the resistor divider is certainly no Electrical
Engineer, and I'm glad I don't own any products that are designed so poorly.

In any event, I want to resurface an old question that (I think) was asked:
someone mentioned the need to modify the motherboard when adding the 6 volt
supply, yet someone else countered this.  I think the point is that you need to
avoid sending 6 volts to every chip in the Apple.  Since the ribbon cable from
the TransWarp GS sits in the 65C816 socket, I would assume that AE connected
the 5 volt signal from the motherboard CPU socket to the 5 volt line on the
W65C816 that resides on the accelerator.  If you do not disconnect this contact
at some point (on the motherboard socket, in the ribbon cable, or on the
accelerator socket itself), then any 6 volt supply you generate will be
*shorted* to the Apple 5V supply.  Yikes!

>Since a 13 megahertz 65816 is going to be a pretty penny (does anyone know how
>much, in small quantity?), I'd probably spring for the two-buck regulator.

Call Western Design Center, 602/962-4545, they have no distributors, and they
only sell direct.  Back in July, I ordered a 10 MHz W65C802 for $24.84, 4 MHz
parts were only $17.80.  Minimum order is $50, though, so you'd better have
some friends who are also interested.  Or you could just buy an extra chip for
backup.  Me?  I purchased two 4 MHz and one 10 MHz chips, and only paid $5 for
COD delivery.  Then I sold a 4 MHz chip to a friend with a TransWarp.

Brian Willoughby
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