From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, HTML_MESSAGE,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 17697 invoked from network); 29 Apr 2021 13:18:07 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 29 Apr 2021 13:18:07 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id F1E049C88A; Thu, 29 Apr 2021 23:18:05 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 6C6559C87C; Thu, 29 Apr 2021 23:17:57 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=ccc.com header.i=@ccc.com header.b="jCB1s69W"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id E60429C87B; Thu, 29 Apr 2021 23:17:54 +1000 (AEST) Received: from mail-qt1-f176.google.com (mail-qt1-f176.google.com [209.85.160.176]) by minnie.tuhs.org (Postfix) with ESMTPS id 2627F9C87A for ; Thu, 29 Apr 2021 23:17:54 +1000 (AEST) Received: by mail-qt1-f176.google.com with SMTP id 1so49067056qtb.0 for ; Thu, 29 Apr 2021 06:17:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ccc.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=iBWUwCZMghj9ca6R0rruykPDCM6kWkACP0iSXtlJTCo=; b=jCB1s69WzrF6aMhM7XeH4FYsSQDujrPI3xLb7dRbmS/z1pWkCZx33ktxMdfsCxO9MQ 1ZnnMQJFopB/VIJvO7E8mslb1bgZvTxUREkd0J4SwKvFCrn2h0v9CtqMktV/I/JXchH6 675ZnZc2KX0Vylsc3D3m9MHYF2ulHgUyBdN2o= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=iBWUwCZMghj9ca6R0rruykPDCM6kWkACP0iSXtlJTCo=; b=dSFcseIq6n0WIHYNhrQMsGeTue0DJPZov56sudqAfF9h00eK7zSDrXx+hR+bKAe2qG ntIuW+PHv1RAxY1cvXlWnnd4KO4mq3Fwucptd3nsmh7YR00zQc47ZazTt4DeGiXvMArB iKXosQqNkhTKWtfIklnpHCoyw3lUxGNg6SiYgWvEWy087SgxsoHn32ZJegySQg4BzA/2 NXbB5zHdqUOXXNFBImMi4HREJZ2TFKFYJETAAPmA65rRMXYcahki151R4noY3aGGvvFr 7fQPZEIX2pPXm2I9GxoETFxnFMYVTx6asfkpefixM57csY1VMy77aVwFE861+RagjrZK Hc5A== X-Gm-Message-State: AOAM532aPTfYkFR7FTZuXJXOjb7mJiLgoTPvZfA7XYQdAmyH7us0N3PR p7UOs+mP1mkIBOT/XukAciOu12KddF+6lc8wbMFCwxSvG04= X-Google-Smtp-Source: ABdhPJy/3gKB4yviUH0aTXmD4YXBeZJ5LyaIHnctV/3/TqHlUwW6t4pN5IAIH00rKQIP78ZPMwpKAQ04207AUXVlrCI= X-Received: by 2002:ac8:5812:: with SMTP id g18mr31345980qtg.119.1619702272679; Thu, 29 Apr 2021 06:17:52 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Clem Cole Date: Thu, 29 Apr 2021 09:17:27 -0400 Message-ID: To: Tom Ivar Helbekkmo Subject: Re: [COFF] DEC terminal line driver chips? X-BeenThere: coff@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: Computer Old Farts Forum List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Computer Old Farts Followers Content-Type: multipart/mixed; boundary="===============4650541031336072593==" Errors-To: coff-bounces@minnie.tuhs.org Sender: "COFF" --===============4650541031336072593== Content-Type: multipart/alternative; boundary="0000000000009af93205c11c52fe" --0000000000009af93205c11c52fe Content-Type: text/plain; charset="UTF-8" If you look at the schematics for the VT-100 (which are available on bitsavers) as well as most terminals of the day used the Motorola MC1488/1489 driver pairs [early on, TI marked them as 75488/75498 but I doubt you'll see that old]. Anyway, for any terminal of those times, I'd be surprised if the later devices (like VTx20 series) did not them [the issue with these devices is you need all of 5 and +/- 12 volts]. These terminals are new enough that they might have used MAX232 (single 5 v power - there are even 3.3v versions these days). All of these devices are very available online. I would suggest putting high quality (*i.e.* auget style / machined pins) sockets. The nice thing about 1488/1489 is that they were doped to fuse the output section on failure, so just replacing them will in fact resurrect most serial port failures. Frankly, I never understood why more manufacturers did not put them in sockets for easy replacement. That said before you open up the case, I make sure you are cabled correctly. If you are using so-called 3-wire cables, then you need to ensure RTS/CTS [4-5] are strapped and DSR/DCD/DTR [6/8/20] are also strapped. The terminal will ignore any I/O unless it sees these pins asserted. On Thu, Apr 29, 2021 at 3:11 AM Tom Ivar Helbekkmo via COFF < coff@minnie.tuhs.org> wrote: > I've got a number of DEC terminals, ranging from the VT220 to the VT520 > (sadly, I got rid of my VT100 and VT102 many years ago, before I started > collecting DEC equipment instead of just using it), and some of them > have one or more burned out serial ports. Before I start taking them > apart to find out what chips were used, I figured I'd check if any of > you folks happen to know. I'd like to order a stash of replacements, > and it would be nice to have them handy before I clear the work bench to > start dismantling terminals... > > Oh, and for the record: the Q-bus PDP-11/23 uses 9636ACP and 9637ACP for > output and input, respectively, while the VAX-11/630 substitutes a > 9639ATC optocoupler for the 9637ACP differential receiver. (I have a > couple of spare CPU boards with damaged ports, as well, so these are all > on my shopping list already.) > > -tih > -- > Most people who graduate with CS degrees don't understand the significance > of Lisp. Lisp is the most important idea in computer science. --Alan Kay > _______________________________________________ > COFF mailing list > COFF@minnie.tuhs.org > https://minnie.tuhs.org/cgi-bin/mailman/listinfo/coff > --0000000000009af93205c11c52fe Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
If you look at the schematics for the VT-100 (which are= available on bitsavers) as well as most terminals of the day used the Moto= rola=C2=A0MC1488/1489 driver pairs [early on, TI marked them as 75488/75498= but I doubt you'll see that old].=C2=A0 =C2=A0

An= yway, for any terminal of those times, I'd be surprised if the later de= vices (like VTx20 series) did not them [the issue with these devices is you= need all of 5 and +/- 12 volts].=C2=A0 =C2=A0These terminals are new enoug= h that they might have used=C2=A0MAX232 (single 5 v power - there are even = 3.3v versions these=C2=A0days).=C2=A0 All of these devices are very availab= le online.=C2=A0 I would suggest putting high quality (i.e. auget=C2= =A0style / machined pins) sockets.=C2=A0 The nice thing about 1488/1489 is = that they were doped to fuse the output section on failure, so just replaci= ng them will in fact resurrect=C2=A0most serial port failures.=C2=A0 Frankl= y, I never understood=C2=A0why more manufacturers=C2=A0did not put them in = sockets for easy replacement.

That said before you ope= n up the case, I make sure you are cabled correctly.=C2=A0 =C2=A0If you are= using so-called=C2=A03-wire cables, then you need to ensure RTS/CTS [4-5] = are strapped and DSR/DCD/DTR [6/8/20] are also strapped.=C2=A0 =C2=A0The te= rminal will ignore any I/O unless it sees these pins asserted.=C2=A0
<= /div>
O= n Thu, Apr 29, 2021 at 3:11 AM Tom Ivar Helbekkmo via COFF <coff@minnie.tuhs.org> wrote:
I've got a number of DE= C terminals, ranging from the VT220 to the VT520
(sadly, I got rid of my VT100 and VT102 many years ago, before I started collecting DEC equipment instead of just using it), and some of them
have one or more burned out serial ports.=C2=A0 Before I start taking them<= br> apart to find out what chips were used, I figured I'd check if any of you folks happen to know.=C2=A0 I'd like to order a stash of replacemen= ts,
and it would be nice to have them handy before I clear the work bench to start dismantling terminals...

Oh, and for the record: the Q-bus PDP-11/23 uses 9636ACP and 9637ACP for output and input, respectively, while the VAX-11/630 substitutes a
9639ATC optocoupler for the 9637ACP differential receiver.=C2=A0 (I have a<= br> couple of spare CPU boards with damaged ports, as well, so these are all on my shopping list already.)

-tih
--
Most people who graduate with CS degrees don't understand the significa= nce
of Lisp.=C2=A0 Lisp is the most important idea in computer science.=C2=A0 -= -Alan Kay
_______________________________________________
COFF mailing list
COFF@minnie.tuhs.= org
https://minnie.tuhs.org/cgi-bin/mailman/listinf= o/coff
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