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 Can You Scrap Your Old Projects? 
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Joined: Wed Jan 16, 2013 2:33 am
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Can You Scrap Your Old Projects?

A look at wire wrap and how hard it is.

http://www.miser-tech.com/2016/01/can-y ... -projects/


Wed Feb 10, 2016 5:09 pm
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Joined: Tue Jan 15, 2013 10:11 am
Posts: 114
Location: Norway/Japan
Well.. I'm of the opinion that there's no point in throwing something away unless it's garbage, as long as it doesn't do any harm where it is (there's no acute lack of room, for example). This way of thinking isn't fully shared with, shall we say, everybody nearby..


Wed Feb 10, 2016 5:54 pm
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I have a hard time throwing away my broken Amiga because I might want to pull the SID chip from it.

I'm hoping that I will find a product which isn't too expensive to read my old disks.


Wed Feb 10, 2016 6:25 pm
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Location: California
Out of the dozens—maybe 100+—projects I've done over the decades, I'm hard-pressed to think of any I totally tossed. I can think of a few that were taking up too much space and I knew I would never use them again so I rescued an important portion and tossed the rest of it. One is a huge turntable I made in the late 1970's when I was still in high school. (Today's young people won't know what a turntable or a tone arm is.) The rotating turntable and drive portion came from a junked cheap turntable whose tone arm was not worthy of fine music reproduction or taking care of records; but my real pride (as amateur as I was, and not having decent tools available) was in the tone arm with light, accurate tracking and anti-skate, so I took that off and saved it. The phono cartridge was an Empire with specs that were well beyond those of the Shures and most other audiophile cartridges of the day.

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At the same time, I was interested in recording (not computers), and I made this headphone amp that had some mixing-board features:

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I laid the boards out with pencil, then drilled, and painted the etch resist on the back before putting the boards in ferric chloride. It had very low distortion and noise which today is surprising to me as I look back at how much knowledge I lacked in circuit design. There was not a single IC in it. The only active components in it were discrete transistors. The unit went in a wooden equipment rack I made, with other things I made. I did get rid of the rack itself.

I think I got rid of a crude transistor curve plotter after I made a better one. An RF complex-impedance tester (since I was into amateur radio also) sits dormant but I can't bring myself to throw it out even though I know I'll never use it again. If I want something like that now, I'll take a better approach.

My Ol' #1 computer from 1985 is in pieces in a box. It worked but was not really useful. I learned a lot from it though, which I built upon for two portable workbench computer efforts around 1990 that I never finished and also won't throw out, before building the workbench computer I have been using for 20+ years (with improvements over the years).

I have loads of working breadboards for work projects that got backburnered and later pushed off the back of the stove. I can't bring myself to throw those out. Another engineer in the company said, "There's a lot of good stuff behind that stove!"

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Wed Feb 10, 2016 6:57 pm
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Joined: Tue Jan 15, 2013 5:43 am
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I hate to throw stuff out. But I realized some of the treasures I was storing had no value other than sentimental value -- IOW as mementos.

My solution is to TAKE A PICTURE and *THEN* THROW THE DARN THING OUT!!

Here are two selections from the folder I named Relics for the Recycle Bin. The carcass of a nine-track tape drive, and a klugey ROM emulator using an NMOS 2K x 8 RAM.

-- Jeff
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Tue Feb 16, 2016 3:27 pm
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Do you need any tips on DIP extraction?!


Tue Feb 16, 2016 5:17 pm
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That poor DIP! :(

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Tue Feb 16, 2016 9:55 pm
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Love the 9 track drive though. Has anyone experience with using a proper seekable open reel tape drive with an 8-bit micro?

I remember back in the day, when floppy drives were too expensive and audio cassette tape was the only option for mass storage, that the possibility of a computer-driven drive which could seek and rewind was very attractive. The Hobbit aka Ultradrive was probably the one I saw advertised:
http://forum.6502.org/viewtopic.php?p=20832#p20832

Nice video of pneumatic auto-loading tape here: HP and Overland 9-Track Tape Drives Demo


Wed Feb 17, 2016 11:29 am
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Joined: Tue Jan 15, 2013 10:11 am
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The horizontal beige one in that video is quite similar to my Anritsu 9-track drive. It's a heavy beast. SCSI interface, I use it with an SGI Octane with a differential SCSI interface.
I've read a ton of my old CCTs going back to 1986 or earlier with that drive.


Wed Feb 17, 2016 6:17 pm
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BigEd wrote:
Love the 9 track drive though. Has anyone experience with using a proper seekable open reel tape drive with an 8-bit micro?

I remember back in the day, when floppy drives were too expensive and audio cassette tape was the only option for mass storage, that the possibility of a computer-driven drive which could seek and rewind was very attractive. The Hobbit aka Ultradrive was probably the one I saw advertised:
http://forum.6502.org/viewtopic.php?p=20832#p20832

One of the breadboards sitting around here that I'm sure I'll never use again but I can't bring myself to throw out is a tape modem I made after the design I did for work in about 1987. The tape drive got deleted from the overall product design before we went to market, but we were using a cassette transport that had no buttons but rather solenoid control, so the computer could control it. The computer also watched an optocoupler gizmo that was on the transport which watched silver and black stripes on a wheel under a reel table, for a tape counter. Then the computer could search the FAT for the desired file, get its position, then fast-forward out to it by watching the optocoupler but stop a little short of it and start reading the tape again to make sure it didn't overshoot the target.

Play, record, FF, and REW were all under computer control. It was only 300bps, but that was enough for the application, and it was very reliable. To experiment with things like the timing of the pulses to the solenoids, the other engineer brought in his C64 and CMRI (computer-to-model-railroad interface) since he was also a model-railroad enthusiast). That was his "workbench computer" in a sense.

For some reason I can't totally identify, tape has always given me a nice feeling. Today it's hard to justify it, especially for keeping data. (There are still a couple of companies making professional-quality audio recording tape though, and there is a Swiss company that's developing a new open-reel high-end consumer tape recorder: http://www.chartattack.com/news/2016/01 ... reel-next/ .)

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Wed Feb 17, 2016 7:40 pm
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BigEd wrote:
Love the 9 track drive though. Has anyone experience with using a proper seekable open reel tape drive with an 8-bit micro?

I remember back in the day, when floppy drives were too expensive and audio cassette tape was the only option for mass storage, that the possibility of a computer-driven drive which could seek and rewind was very attractive. The Hobbit aka Ultradrive was probably the one I saw advertised:
http://forum.6502.org/viewtopic.php?p=20832#p20832

Nice video of pneumatic auto-loading tape here: HP and Overland 9-Track Tape Drives Demo

Sorry for continuing to drift off-topic....

In ETI September 1984 there was a digital cassette deck project that would run at 4,800 baud. I remember drooling over the thought of making this for my Acorn Atom, but couldn't afford to on my pocket money!
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I found an archive copy of the complete issue:
http://americanradiohistory.com/Archive ... 984-09.pdf

As part of an partial ETI archive:
http://americanradiohistory.com/ETI_Magazine.htm

As part of a massive archive of electronics magazines:
http://americanradiohistory.com/#TECHNICAL

Dave


Thu Feb 18, 2016 7:55 am
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Joined: Wed Jan 09, 2013 6:54 pm
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Great find!


Thu Feb 18, 2016 8:50 am
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Joined: Tue Jan 15, 2013 10:11 am
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I found a "brand new" Tanashin open tape drive that could possibly be used as an alternative to the drive in the article (an older Tanashin). Only $5.. but shipping is $128, so I'll pass. Would be a fun project though..


Thu Feb 18, 2016 9:15 am
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Since he's getting 4800 bps, I have to wonder how reliable it is. I'm quite familiar with the problem of tape dropouts. (I worked at TEAC's North American HQ in the early 1980's, and have a degree in recording.) There were so many such tape transports made for audio, and it seems that there would have been a plenty big market to do the same thing with a slight variation for a faster tape speed for digital use, so it's kind of surprising it wasn't done. That magazine archive is absolutely incredible though! Wow!

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Thu Feb 18, 2016 10:36 am
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