Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!ll-xn!mit-eddie!uw-beaver!fluke!jfadams
From: jfadams@tc.fluke.COM (Jim Adams)
Newsgroups: comp.sys.atari.st
Subject: Re: HP DeskJet problems
Message-ID: <3636@fluke.COM>
Date: 3 May 88 19:19:07 GMT
References: <8804261549.AA04870@decwrl.dec.com>
Sender: news@tc.fluke.COM
Organization: John Fluke Mfg. Co., Inc., Everett, WA
Lines: 29

In article <8804261549.AA04870@decwrl.dec.com> paulhus@euclid.dec.com (N. Chris Paulhus DTN 223-6871 MLO 8-3/T13) writes:
>
>  I'm having problems getting a Hewlett Packard DeskJet printer
>  to communicate with my ST. ...
>

I have a similar problem with my LaserJet Series II.  It works fine with my
Epson IBM Clone, but refuses to print anything sent by my ST.  The problem
lies in the termination resistors in the HP.  Their values are < 2 kOhm, and
require more current to drive than the Yamaha chip in the ST can deliver.
The solution, according to Atari's Service Bulletin (I saw a copy this week-
end), is to replace the termination resistors in the printer with higher
valued resistors >3.3 kOhm, [or buy an Atari printer ;^)].

I tried replacing the 1 kOhm pull-up R107 (I think) on my ST mother board with 
other values to no avail.  At least I have an out of using the serial port
on the LaserJet with my ST.  I don't believe the DeskJet has one.

I know this doesn't solve your problem, but I hope it answers your question.

Oh, incidently, I'm told that not all STs exhibit this behavior.  Wonderful,
no?  I've already had to replace my marginal DMA chip so I could communicate
with my Hard Disk, my MMU [sic] so I could run Spectrum, and now they tell
me I need to replace my Laser Printer! :^|

-- 
James F. Adams       John Fluke Mfg. Co., Inc.        Everett, Washington USA
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