Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!udel!rochester!kodak!uupsi!sunic!news.funet.fi!ujocs!jlavi
From: jlavi@ujocs.joensuu.fi (Jarkko Lavinen)
Newsgroups: comp.sys.amiga.hardware
Subject: What does hot PALs mean in Lucas ?
Message-ID: <1991Feb17.115538.23465@ujocs.joensuu.fi>
Date: 17 Feb 91 11:55:38 GMT
Distribution: comp
Organization: University of Joensuu, Finland
Lines: 24


	Answer: Smoke

	I have Lucas accelerator in my A1000 and guess what: It does not
work!

	Led flashes, I can hear the boot song. With 7474 as U9 I can
even load kickstart disk. After that power led really starts to flash
and in sequence I can see different colors in screen (at least grey,
yellow, green...).

	The interesting thing is that PALs U4 (Eclk, decade, CPCS) and U5
(VMA, HIGHZ) are running exceptionally hot. I don't dare to keep my
machine on as smoke may not be far away.
	Within few days I hope I get logic probe at my hands so I will
check few lines but until then digital multimeter is my only guide. At
least I check better U4 and U5 outputs. With multimeter I have checked
that the outputs are not shorted. 
	What else can it be? What can load PAL's so much that they warm
so exceptionally ? They receive clock, I think (at least the pin voltage
is in forbidden area, so it's probably pulsing).

	Jarkko Lavinen