From:	SMTP%"RELAY-INFO-VAX@CRVAX.SRI.COM" 28-JUN-1994 16:32:45.35
To:	EVERHART
CC:	
Subj:	Re: VS3100 hardware questions

From: evm@opo.van.wa.us
X-Newsgroups: comp.sys.dec,comp.os.vms
Subject: Re: VS3100 hardware questions
Message-ID: <1994Jun28.101553.178@opo.van.wa.us>
Date: 28 Jun 94 10:15:53 PST
Organization: OPO Observatory, Vancouver, Wa
Lines: 45
To: Info-VAX@CRVAX.SRI.COM
X-Gateway-Source-Info: USENET

In article <2uneel$15m@agate.berkeley.edu>, avk@hafnium.cchem.berkeley.edu (Tony Konashenok) writes:


>From: avk@hafnium.cchem.berkeley.edu (Tony Konashenok)
>Subject:VS3100 hardware questions
>Date: 27 Jun 1994 20:56:53 GMT
>Message-ID:<2uneel$15m@agate.berkeley.edu>

>I've started to fiddle with the configuration of my 3100/40 and came
>up with the following questions:
>

>4. There's a rumor that 3100/40 is easily convertible to /48. Which
>   quartz oscillator should I change, to what value, and what else
>   should be changed?
>

Hi tony,

        In answer to question 4, its no rumor. I was the one who figured out
how to do it. I published the procedure on the internet. It's been picked up
by Terry Kennedy and others.

In summary you remove the 44 MHz oscillator and replace it with a 66.666 MHz
one and move a jumper. You can upgrade the rom but it is not required. There
are at lease 3 versions of the motherboard so get the board number and I'll
tell you where the jumper is. I am using a converted VS3100 to type this
message. I myself, put a socket on the board and have used osc from 30 MHz to
74 MHz. The 66 MHz is the best due to cache access times. That is to say, With
a 74MHz clock the machine runs the DRlabs benchmarks slower than with a 66 MHz
osc.

        Let me know if you want to proceed with this. It is not for the faint
at heart as that you need to take a perfectly good motherboard and unsolder
the osc in very tight quarters. No oops allowed...

	I get requests for my original how to do posting every now and then so 
I should update it and put it out for ftp...

Best regards, Ethan
........        ........        ........
OPO Observatory
17104 ne 35th Cir       Ethan VanMatre
Vancouver, Wa 98682     evm@opo.van.wa.us