Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hplabsz!dleigh
From: dleigh@hplabsz.HPL.HP.COM (Darren Leigh)
Newsgroups: comp.sys.amiga.tech
Subject: TICK and J300
Summary: B2000 power supply fixed!
Message-ID: <3319@hplabsz.HPL.HP.COM>
Date: 11 May 89 19:08:48 GMT
Reply-To: dleigh@hplabs.UUCP (Darren Leigh)
Distribution: na
Organization: Hewlett-Packard Laboratories
Lines: 30

Well, "board-swapped" would be a better term.  Does this make me an
offical customer engineer? :-)

I didn't really want to try to fix the amiga power supply itself
without schematics so I bought a 200W AT clone power supply for $60
and used that.  Since the power supply cases weren't the same form
factor, I couldn't just slide the new one in.  Thanks to defacto
manufacturing standards that the PC industry has (thanks to evil IBM),
the boards inside the two power supplies were practically identical
and I just put the new board inside the old case.  Some connectors and
wire later, I had a power supply that worked nicely, minus the TICK
line which was the one subtlety.  I take it that this has some sort of
60 Hz clock on it?  My 2000 didn't work until I changed jumper J300
from "normal" to "A500".  What do I gain/lose by not having a power
supply TICK?  Will it matter at all?

Are the schematics for this jumper wrong?  For "normal" operation, the
schematics say that J300 should be jumpered between pins 2 and 3.  I
found it jumpered between 1 and 2 and had to change it the other way
to get it to work without the TICK line.  What's going on?

P.S.  Mucho thanks to C-A for putting the 2000 schematics right in the
back of the intro. manual which is included with every machine.  Also
kudos for making the TICK line jumperable.  I hate having to cut and
solder.

========
Darren Leigh   (415) 857-6713 (w), (415) 967-8102 (h)
Internet:  dleigh@hplabs.hp.com
UUCP:      hplabs!dleigh