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- From: pfeiffer@nmsu.edu (Joe Pfeiffer)
- Newsgroups: comp.sys.amiga.hardware
- Subject: Help understanding Fatter Agnus hack
- Message-ID: <1992Aug27.160917.6264@nmsu.edu>
- Date: 27 Aug 92 16:09:17 GMT
- Sender: usenet@nmsu.edu
- Distribution: comp
- Organization: NMSU Computer Science
- Lines: 36
-
- I tried to e-mail this to the Provider Of The Hack, but my mailer
- didn't recognize his site:
-
- To: safc@cs.UAlberta.CA
- In-Reply-To: Neil Brown's message of 9 Jul 92 00:00:57 GMT
- Subject: rev 5 1meg Agnus hack explained
-
- Hi, I just got my Fatter Agnus and my 2.04 upgrade, so I've been going
- over your instructions and my A500 schematics. I'm a little puzzled...
-
- I assume the schematics are wrong about JP2 -- it shows a single
- jumper, optionally connecting U32 and U13 to U5 (Gary). There's also
- an annotation saying that U32 and JP2 are mutually exclusive. I would
- guess that when I open the case, I'll find that JP2 actually selects
- whether U32 or U5 drives the U13 pin? Will I be changing from U32
- driving to U5 driving, or vice versa?
-
- Also, looking at pin 32 of the connector, it is grounded on the A501
- card. It appears to be telling Gary that the card is in fact present
- (_EXRAM input to U5) -- with it cut, how will the system determine the
- presence of the A501? Does it query a memory location?
-
- I haven't found anything on the schematic to say which rev level I have.
-
- Thanks for your help, I'm just finding out what I'm doing before I do it...
-
- Since this is going out to the net, let me add:
-
- By the way, my Fatter Agnus came without installation instructions;
- also, for what it's worth, my ``2.04'' upgrade turned out to be a
- 2.05! Contrary to my dealer's expectations, it only took a couple of
- weeks to come in. My Quantum 240 MB disk drive is taking just this
- side of forever, with dark hints that the price may have gone up $200
- in the interim...
-
- -Joe.
-