Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!cacilj!close
From: close@cacilj.UUCP (Diane Barlow Close)
Newsgroups: comp.sys.atari.st
Subject: SERIOUS DeskJet Plus Problem!
Keywords: disconnect your printer NOW!
Message-ID: <1024@cacilj.UUCP>
Date: 4 Jun 89 04:41:33 GMT
Reply-To: close@cacilj.UUCP (Diane Barlow Close)
Organization: CACI Products Company, La Jolla, CA
Lines: 39

Roger Hunen (awinfhah@hmarl5.bitnet) writes:

-> This may be old news, but since I haven't seen the issue here for several
-> months, I'll (re)start it. If you have a NEC P2200 printer connected to
-> your ST *without* modification,
->
-> **** DISCONNECT IT NOW ****
-> 
-> The P2200 has 1k pull-up resistor on the Centronics port. This may eventually
-> kill the sound chip in the ST. (1k pull-ups may cause up to 5mA of sink
-> current, whereas the sound chip can only handle 1.6 mA.)

I've been having some strange problems with my recently-purchased DeskJet
Plus, and I suspected a similar problem with resistors.  I wrote Dave Neff
of H.P. (neff@hpvcla) and he wrote back:

-> I showed your latest letter to the DeskJet+ electrical engineer and he
-> said we have a 1K pullup resistor on the strobe line and 2.2K pullup
-> resistors on each data line.  The 2.2K resistors result in about 2ma
-> of current and the 1K about 5 ma.  So I might be concerned if I
-> were you.
-> 
-> If this problem is confirmed our support position may have to be  
-> DeskJet+ should not be used with Atari STs.  How can we be sure
-> there really is a problem?

So, how can we be sure there *is* a problem?  This looks serious.  Any
DeskJet Plus owners might want to heed Dave Neff's warning and only use the
serial port for printing (or buffer your lines!).

I don't know if this is a problem with (plain) DeskJets or not--can anyone
confirm/disprove it?

:-(  :-(  :-(  :-(  :-(  :-(  :-(  :-(  :-(  :-(  :-(  :-(  :-(  :-(  :-(  
-- 
Diane Barlow Close
      {uunet, crash, ucsd}!cacilj!close
      close@cacilj.uucp
      Free Canada -- Trade Mulroney