[GreenKeys] Need ASR33 repair help, in Ann Arbor MI

Sat Nov 29 14:55:55 EST 2014

Keith,

With the 33 ASR in full duplex, 4 wire, the distributor is only used when the tty is sending to a computer or device in LINE mode.  If you want a copy of what you are sending you have to enable your computer or device to echo back the copy.  In half duplex, 2 wire the printer will print whatever you are sending.  Most 33's in half duplex are also using 60 MA current loop.  There are always exceptions to the common above modes.  

In LOCAL mode the 33 is using the distributor all the time.  The distributor is a carbon brush faceplate with 1 start bit (always a space) and 8 character bits (mark or space depending on what contacts are selected in the KB, TR or AB)
and one stop bit that is two bits long.  After a character is typed the dist stays in the stop segment to keep the 33 printer current loop closed.  

Hope this helps.

Wayne
KB1FDW

-----Original Message-----
From: drlegendre . <drlegendre at gmail.com>
To: Teletypeparts <teletypeparts at aol.com>; GreenKeys <GreenKeys at mailman.qth.net>
Sent: Fri, Nov 28, 2014 12:28 am
Subject: Re: [GreenKeys] Need ASR33 repair help, in Ann Arbor MI

Wayne,

For those of us not in-the-know, could you briefly explain the function of the 'distributor' in these machines? Is this a mechanical rotary contactor, the likes of an automotive distributor - less the spark gap, of course? Does it use carbon brushes / wipers and so forth?

@All

How the +HECK+ do you reply in-thread to a greenkeys post? I'm used to communicating with other lists via gmail, where if I hit the 'Reply' field, it sends my reply to the list, and properly threads it. With greenkeys. my replies always go directly, and personally to the last poster - rather than the list et al. 

If you're seeing this post, it's because I tacked a greenkeys reply to the To: field in the mail, which is actually pointed to Wayne / Teletypeparts. Are you all seeing this, properly threaded? If not, how do I handle this properly via gmail?

I can only imagine the duplicate threads and other havoc my alleged contributions might be creating. Thank you for your deference on this occasion of my newbishness. ;-)

-ML

On Thu, Nov 27, 2014 at 10:04 AM, Teletypeparts via GreenKeys <greenkeys at mailman.qth.net> wrote:

Keith,

I dont live near your location but I can give you a few tips.  

Dont type too much without inspecting the rubber hammer that hits the typewheel.  If the rubber hammer falls of or disintegrates you will ruin the typewheel quickly.  

Most 33 troubles can be found by visual inspection.  No adjustments unless you have exhausted the visual stuff.  Look for things out of place like contacts in the keyboard, tape reader and answerback.  

There should be nothing in the machine that needs force to fix or correct.  Go slow.  

33's that have been sitting a long time usually have congealed grease on the codebars and other areas that need freeing up.  The codebars ride on slotted round bars on each end and in the middle.  I use "Breakaway" in those areas very carefully sprayed on.  Very Carefully!  

Dont spray any solvents into the keyboard contacts or other plastic contact areas.  Use a pipe cleaner with some contact cleaner sprayed on the pipe cleaner and clean carefully.  You may not need to do this.  Remember that the kybd, TR and AB contacts are all in parallel feeding the distributor.  Thats why its good to be able to test the printer from another source before assuming that you have printer problems when the problem might be in one of the three subassemblies that feed the distributor.  

Most 33's come with 20 MA full duplex (4 wire) setup in the UCC-6.  You need a current loop to RS 232 adapter to connect to a computer.  Some computers have a current loop interface in them.  PDP's etc.  Ask on Greenkeys.  

I will include some pics that might help identify stuff.  

Happy Thanksgiving from Vermont where we have 4 to 8 inches snow overnight.  

Wayne
KB1FDW

distributor

kybd contacts

codebars

UCC-6

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