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mrpixel
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Re: ASR?
mrpixel   9/11/2013 12:43:48 PM
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Hi,   I have fond memories and some not so fond memories of that ASR33. One might benefit from my experience. I used it mainly as an I/O terminal to a Data General Mini Computer, Nova 3 and 4's...where it worked fine loading bootstraps and user input/output. When microprocessors came out in the middle 70's, I needed the ultimate in reliability for reading 8 KB paper tapes for Basic and other Software.   The BER, Bit Error rate was less than desired, so I found the ASR-33 delighfully easy to take apart, clean, re assemble etc  generall R&R, but often the BER rate when up surprisingly.   The  correct weight lubricant was most important to get ultra reliable operation.. and the correct weight lubricant was much lighter  than I would have ever expected.  I don't remember  specifically what I used, but I believe it was specified in the manual.  Likely the machine will have to be cleaned and likely relubricated.. so pay attention to using the lightest lubricant you can find or specified ..    MrPixel@gmail.com   used the machine at was was then called Highway Safety Research Institute, Ann Arbor Michigan.   Best Wishes   Leigh

TM123
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Re: Fond memories
TM123   9/9/2013 7:57:02 PM
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Fond Memories indeed. I worked at a place that used ASR33s as the interface to Data General DG3s (mini computers from yesterday).

 

Before that, I had a Creed set up to run RTTY (Radio Teletype) on both HF and VHF. For a while, I was broadcast officer for a amateur radio club (HAMs) and was responsible for doing a weekly RTTY broadcast. The problem is when you mis-type a character, you can start from scratch (again!) or just live with it. Broadcast ran for around 5-10 minutes at 50 baud. You can imagine the amount of paper tape consumed in the process. Computers fixed all that.

Setting these up is not for the feint hearted. Max, get someone to do it for you. I knew a bloke who could listen to a TTY and tell you what was being transmitted - kind of like a complicated Morse code.

 

Erickk
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Fond memories
Erickk   9/5/2013 8:48:11 PM
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I first used these in high school, connected over leased current loop lines (Ma Bell) to a shared computer in an adjacent school district. When I was in college (30+ years ago), these were all over, some hardwired, some on Anderson Jacobsen 110 baud modems in wooden boxes.  The ASR33s were under service contract.  When one would break, the service provider would bring a complete replacement machine, at no charge, provided they did NOT have to take the old one back.  It seems that as these machines became obsolete, they had a warehouse filled with ones fresh off lease.  Our broken machines were carted away to a room in the basement of the Buchard Building, housing EE and Physics.  Soon we didn't bother calling service, as it was faster to scavenge parts from the growing pile in the basement.  Every once in a while, rumaging through my junk at home, I come upon a motor start relay from an ASR33.

Max The Magnificent
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Re: ASR?
Max The Magnificent   9/5/2013 7:09:56 AM
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 @David: I could do a program for this in BASIC quite easily, just a lookup table really.

As you say, this should be a pretty easy program to create ... I'll add it to my list of things to do :-)

Max The Magnificent
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Re: Line feed
Max The Magnificent   9/5/2013 7:08:26 AM
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@n1ist: The printer can be removed and flipped over to fix it, but remember that the punch and reader are both driven from the print mechanism and are connected.

I now have links to all the maintanance manuals online ... so it may come to that -- but I still live in hopes of finding someone local who used to maintain these, because they coudl do it so much faster and more efficiently...

 

Max The Magnificent
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Re: Authenticity
Max The Magnificent   9/5/2013 7:06:07 AM
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@JeffL_2: ...if you really want to be authentic, where's your acoustic coupler?


Oooooh ... now there's an idea!!!

Max The Magnificent
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Re: Authenticity
Max The Magnificent   9/5/2013 7:04:49 AM
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@JeffL_2: I couldn't afford the space anymore and it was not in good enough shape to be worth the trouble...

As a worst case scenario, some fine upstanding young engineer (like myself, for example) could have used it for spare parts ... I'm just sorry you threw it away (sad face)

Max The Magnificent
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Re: Authenticity
Max The Magnificent   9/5/2013 7:03:27 AM
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@JeffL_2: I couldn't afford the space anymore and it was not in good enough shape to be worth the trouble...

You could probably have found someone who would have treasured it "as-is" at your local Hamfest (I bet if I'd taken it to the Huntsville Hamfest a couple of weeks ago I woudl have been mobbed).

Max The Magnificent
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Re: Authenticity
Max The Magnificent   9/5/2013 7:01:01 AM
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@JeffL_2: ...but I couldn't afford the space anymore and it was not in good enough shape to be worth the trouble and besides all the computer museums said they wouldn't be interested even if it were new fresh in the box.

I simply cannot believe that anyone wouldn;t want one fresh out of the box -- especially museums ... it's a sad world...

 

David Ashton
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Re: ASR?
David Ashton   9/5/2013 4:53:31 AM
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@Rick I used to do that manually with my old Baudot machines.  You just needed to know what characters to use to get the right holes in the tape.  for instance "Z" gave the two outside holes and "C" gave the 3 inside holes (only 5 bits remember!) so to get an "O" on the tape you'd key CZZZC.  The problem as I remember was getting a space with no holes punched in the tape.   Of course Max's machine is ASCII so that would probably make it easier.  And with 7 holes in the tape you could do 7x5 characters instead of my 5x5 ones.  I could do a program for this in BASIC quite easily, just a lookup table really.

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