Newsgroups: comp.sys.ibm.ps2.hardware
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!ira.uka.de!fauern!NewsServ!kluge
From: kluge@Informatik.TU-Muenchen.DE (Oliver Kluge)
Subject: Re: Here's some info on MCA SoundBlaster
Message-ID: <1991Apr13.155327.17657@Informatik.TU-Muenchen.DE>
Keywords: Soundblaster MCV
Sender: news@Informatik.TU-Muenchen.DE
Organization: Department of Mathematics and Computer Sciences, Munich Institute of Technology
References: <1991Apr9.125612.464@husc3.harvard.edu> <1991Apr10.064142.2900@d.cs.okstate.edu> <1991Apr12.142219.23990@Informatik.TU-Muenchen.DE>
Date: Sat, 13 Apr 1991 15:53:27 GMT
Lines: 52

Hi out there!

I have now found the solution to the problems with the
Soundblaster Micro Channel Version.
I you have read my previous article on the issue, the
Soundblaster MCV is incapable of correctly operating
the joystick interface on a machine with 16 MHz or faster.

The culprit for this is a simple OR gate (74LS32) on the
board. It is seemingly much too slow to follow a Micro
Channel IO Write command.

This is obviously a design fault by the Creative Lab
EE designers. This has to be considered a serious bug
in the ciruitry of the board. Obviously they have failed
to recognize that a Micro Channel runs at much higher
clock speeds than normal AT busses and failed to use the proper
TTL IC family for this task (Low Power Schottky (LS) is just
not fast enough, compared to Advanced Low Power Schottky (ALS)
Advanced Schottky or Fast (AS or F). I am sending a fax to
Creative Lab suggesting them to stop delivery of the
board until the bug is fixed.

I strongly suggest to all who want to buy Soundblaster MCV
and want to use the joystick interface (the audio parts all
work well) look at the following chip:

U23 (this is the second from the left and the second from
the bottom, just directly above the jumper J1).

If a 74 LS 32 is soldered in there, reject the board or
DEMAND a test in YOUR OWN MACHINE from your dealer. If there
are 74 ALS 32, 74 F 32 or 74 AS 32, the board should run o.k.

And here is how to solve the proble if you already bought one,
it does not run the joystick AND IF YOU ARE EXPERIENCED IN
HANDLING TTL IC !!!

Apply all the usual precautions against static electricity.
Carefully de-solder U23 (74 LS 32) using a vacuum solder pump.
Solder in a 74 F 32 or 74 ALS 32. This should be it.
WARNING: DO NOT DO THIS UNLESS YOU REALLY ARE EXPERIENCED
IN THIS. OTHERWISE, YOU LOSE YOUR WARRANTY AND DAMAGE TO
THE BOARD AND YOUR COMPUTER MIGHT OCCUR.

So, enjoy your Soundblaster MCV! It really is a great
thing to have in a PS/2 (if they remove the bug...)

Oliver Kluge