Path: utzoo!attcan!uunet!nih-csl!lhc!ncifcrf!haven!aplcen!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!usc!apple!olivea!tymix!tardis!jms
From: jms@tardis.Tymnet.COM (Joe Smith)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Help!  Fried chips!
Summary: both 8520 chips.
Keywords: parallel cable, voltage, chips, help
Message-ID: <1308@tardis.Tymnet.COM>
Date: 26 Oct 90 06:14:47 GMT
References: <1990Oct24.193736.18642@uncecs.edu>
Reply-To: jms@tardis.Tymnet.COM (Joe Smith)
Organization: BT Tymnet, San Jose, CA
Lines: 19

In article <1990Oct24.193736.18642@uncecs.edu> ruslan@uncecs.edu (Robin C. LaPasha) writes:
>	1.  Friend (accidentally) plugged in a printer cable (parallel port)
>AFTER powering up his Amiga 2500/30.  (He DID know better, but had the
>power switch toggled the wrong way...)  Now it won't boot.
>(It goes dark screen-light gray screen-white screen and then stops, hangs.) 

Pins 1-9 of the parallel port go to CIAA.  This 8250 chip (at position U300)
also reads 4 input signals from the floppy port.  Pins 10-13 of the parallel
port go to CIAB.  This 8250 chip (at position U301) controls the serial port
and 8 output signals to the floppy port.

Your friend probably needs to replace both 8250's.  They are semi-custom
chips; get them from an Amiga dealer or Commodore.

-- 
Joe Smith (408)922-6220 | SMTP: jms@tardis.tymnet.com or jms@gemini.tymnet.com
BT Tymnet Tech Services | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jms
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San Jose, CA 95161-9019 | humorous dislaimer: "My Amiga 3000 speaks for me."