Keyboard Help

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Joined: Dec 31 2004
Posts: 15

I discovered this wonderful site a few days ago, and it inspired me to get my old Apple I out of storage and see if I could get it fired up. It hasn't been turned on since about 1978, so I didn't know what to expect. It was quite dead indeed, and it took a couple days to troubleshoot the problem (the hardest part was finding my old logic probe). The clock was dead, but I was able to pirate a crystal off an old Apple II parts board, and today it is alive once again. That's the good news. The bad news is that the keyboard is still a bit funky. It's a Datanetics ASR-33, and I've isolated the problem to a bad chip, but I can't seem to find any reference to the part number on the chip to locate a replacement. The chip (there are actually 3 of this part) is labeled:
TN 506C F 7524. This number doesn't show up anywhere I've done searches. I suspect that it was either a custom chip that Datanetics had made for this use, or something that they just had labeled with their own nomenclature. At any rate, if anyone has a clue what it is, or what a possible substitute is, it would be very helpful.

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Joined: Dec 20 2003
Posts: 149
I would suggest buying an new

I would suggest buying an new ascii keyboard. And after yo get it working. I would buy a Apple I replica.

http://home.comcast.net/~vbriel/index.htm

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Joined: Dec 31 2004
Posts: 15
Buying a new keyboard is not

Buying a new keyboard is not really an option. A new one likely wouldn't fit into the case that my Apple I is in. Also, it wouldn't be as historically accurate as it is with the original Datanetics keyboard that it has always had. I want to keep it as original as possible.

I've looked at the Replica Apple I. It looks really cool. A good way to tinker with Apple I software without risking "wear and tear" on the real thing.

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Joined: Dec 31 2004
Posts: 15
Problem solved

Problem solved. The faulty chip turns out to be a common TTL logic chip (7404 Hex Inverter). I deduced this by drawing the circuit from the traces on the PCB and figuring what the function of the chip must be to work in that circuit. I replaced the chip with a 7404, and the keyboard works fine. My Apple I is a happy camper again ;D

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Joined: Dec 20 2003
Posts: 249
Nice work. So you have your A

Nice work. So you have your Apple 1 fully working? Do you have pictures? Do you have any software? We are trying to get the Apple 1 library going with as many original programs as possible.

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replica 1 The Apple 1 replica and the new Micro-KIM!
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Joined: Dec 31 2004
Posts: 15
Yes, It's Alive!

My Apple I is fully functional now. I just tested the cassette interface by entering the ASCII Character Output routine from the manual and writing it to tape. Then I cleared memory and was able to reload the program from tape with no problems. I have NO software for it. I used to have a batch of cassettes, but they seem to have vanished from the place I thought they were stored in. I could only find some early Apple II cassettes. I downloaded some MP3 files of Apple I BASIC and 3 games and from this site:
http://iceandfire1.tripod.com/apple1site/index.html
but there seems to be problems with each of them. Half of them don't ever give a cursor back during a read, and the ones that do seem to load have a lot of garbage at their entry points.

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Joined: Dec 20 2003
Posts: 249
Your cassette problem sounds

Your cassette problem sounds pretty typical of the problems associated with the cassette interface. This is why I'm having a tough time with it now. Can you create and load your own programs? The serial I/O board I designed for the replica will also work with the Apple 1 computer. It piggybacks into the socket of the 6820 and the 6820 then goes into the serial I/O board. This method basically types in everything that is sent from a pc into the serial I/O board and captures everything going to the monitor and sends it to the serial port. Makes for an easy way to store and load programs. Program loading is much slower but is much more accurate than the cassette.

Cheers,

Vince

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replica 1 The Apple 1 replica and the new Micro-KIM!
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Joined: Dec 31 2004
Posts: 15
Cassette OK

Yes, I can create and save programs to cassette and then reload them back into the computer with no problems. I'm just having troubles loading these programs from MP3 files. I think the files may be corrupted from the MP3 encoding.

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Joined: Dec 20 2003
Posts: 249
Ask Larry and I'm sure he wou

Ask Larry and I'm sure he would make a CD of the wave files if he still has them. Actually, you maybe the best hope lately of somebody reading the rest of the tapes. Using other methods Basic and Lunar lander have been recovered but I'd like to get all the others recovered and archieved as well.

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Joined: Dec 31 2004
Posts: 15
Old tapes

It's possible that old tapes may be unreadable. They may be partially degaussed and degraded with age. I know that my interface is working fine for both reading and writing, but whether I can read tapes made years ago is another question. I'm certainly willing to try. This may be the problem that I'm having with the MP3 files that won't load properly. It they were digitized from an old tape that has degraded, then just making an MP3 isn't going to make them readable, but if I write a fresh signal straight out of my working cassette interface to an MP3 encoder, then you've got something.

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Joined: Aug 17 2004
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I was just curious, what do c

I was just curious, what do cassette programmes sound like when played through speakers or something?

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Joined: Dec 31 2004
Posts: 15
Cassette sound

They have a solid tone of 1khz for 10 seconds (the header) then it sounds like a bunch of static in the 1khz to 2 khz band. I'll attach one of the MP3's to an email and send it directly to your email address. Just drop it on your Quicktime player (or any other app that plays MP3 like iTunes, etc) and play it.

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Joined: Dec 20 2003
Posts: 67
Cassette Interface

It is really great hearing that someone has an Apple-1 up and running. The tapes I put on my web-site have not been tested, except for the LUNER LANDER one. It was sucessfully decoded and the listing can be found on Vince Briel's site. I simply copied the original tapes to a computer and saved the files. The tapes were copies of the original files, over 20 years old, and recorded on cheap tapes. I am not surprised if the quality is so poor that they can no longer be read. Apple-1 cassette interface was notorious for how critical the volume, tone, tape speed and general quality of the saved programs. I have a CD of the Apple-1 Owners Club Library tapes I will be glad to make available to anyone who has an Apple-1.

Email me at:
iceandfire(at)epowerc.net

and I will send you a CD. Hook a CD player to the cassette interface and experiment with the recordings. Here's hoping that these will be better than the ones on my web-site.

By the way, tell us a little history of your Apple-1. Have you had it for all these years, or did you recently purchase it? Is it in a case? What kind? Where did you buy it? WHat have you done with it?

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Larry Nelson

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Joined: Dec 31 2004
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MP3 files

I did a little more investigation of the MP3 files. I the Lunar Lander MP3 into an application on my Mac that allowed me to look at the waveform of the signal. It showed gaps where the signal flatlines for a few milliseconds. The gaps occur at evenly spaced intervals about 1/2 second apart. Now, knowing the gaps exist, I can hear "clicks" every 1/2 second when I play the audio. This file does not load accurately through the Apple 1 cassette interface. The cursor does not come back after the end of the audio. I have to do a reset to get control again. It is loading stuff though, data is placed in memory locations, it's just not the right data. Another interesting thing that happens with these MP3 files is that the BASIC file gives back a cursor, but it does so a couple seconds BEFORE the end of the audio! It also loads data, but it's pretty much garbage, at least at the entry addresses.

For a benchmark, I entered a page (300.3FF) of alternating 32 byte blocks of 00 and FF to get pure sections of 1000 hz tone during the FF's (all 1's) and 2000 hz tone during the zeros. I wrote this to tape through the cassette interface and captured it on my Mac so that I could look at the waveform and compare it to the MP3. There are no gaps from the cassette interface like the ones present in the MP3, so maybe they were introduced when the MP3 was encoded??? I will email my adress off list so that we can try the CD.

Regarding the history of my Apple I, I bought it about the time t he Apple II came out and have had it since. I will start a new thread regarding it's history since this one is getting a bit long and mutating. I'll also try to get some photos of it on my Mac.Com site this weekend.

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Joined: May 11 2005
Posts: 4
MESS now supports A1 cassette interface - with WAV save/load!

All,

For those not aware, someone else picked up where I left off (so long ago...unemployment sucks, even when brief) with modifying the Apple I driver in MESS and has successfully implemented WAV-based cassette support. This means that for the first time, so long as we can get the stuff to load/patch it appropriately (accounting for audio errors) in MESS just once, we can preserve it -perfectly- forever as WAV data, ready for record back to tape for play on a replica (or the real thing!).

I've done several of these already, but realize there's also a tremendous amount of Apple I software out there still in need of salvation...if -anyone- has a source of WAV (*not* MP3...trust me on this) recordings of any and all Apple I cassette software, I'd like to work with you to restore it back to its original glory.

Thus far, I have rerecorded the following:

Blackjack (BASIC, LOWMEM=768) [1976].wav
Game of Life (2000.21B7) [1970].wav
Integer BASIC (E000.EFFF) [1976].wav
Little Tower (0300.14CD) [2000].wav
Lunar Lander (0300.09B8) [1976].wav
Microchess (0300.0BC7) [1976].wav
Test Program (0000.000A) [1976].wav

I would be happy to host the completed WAVs on my web site (yet to be published) or even on applefritter if space allows (so far the WAVs vary between a meg and 3.5 megs).

Can anyone help?

Rodney

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Joined: May 12 2005
Posts: 5
Re: MESS now supports A1 cassette interface - with WAV save/load

rhester wrote:

For those not aware, someone else picked up where I left off (so long ago...unemployment sucks, even when brief) with modifying the Apple I driver in MESS and has successfully implemented WAV-based cassette support.

That would be me. I'm glad you like it and that it works well for you.

I should have announced the improved driver here earlier, but I was waiting for the next release, and then a bunch of other things came up.

(And I heartily agree with you about unemployment, from my own experience.)

rhester wrote:

This means that for the first time, so long as we can get the stuff to load/patch it appropriately (accounting for audio errors) in MESS just once, we can preserve it -perfectly- forever as WAV data, ready for record back to tape for play on a replica (or the real thing!).

I've done several of these already, but realize there's also a tremendous amount of Apple I software out there still in need of salvation...if -anyone- has a source of WAV (*not* MP3...trust me on this) recordings of any and all Apple I cassette software, I'd like to work with you to restore it back to its original glory.

I used to think that the lossiness of MP3s would be a problem as well, but an earlier discussion here concluded that any losses introduced by the MP3 format would be undetectable by the interface. And the MP3s at http://iceandfire1.tripod.com/apple1site/id2.html loaded fine for me after I converted them to WAV format.

The only problem I had with those files, once I had debugged my cassette interface emulation, was that one or two had some audio glitches at the very start of the tape leader; those were easily avoided by waiting a few seconds after starting the "tape" before hitting Return on the read command.

Noise in the leader can confuse the cassette ROM code into thinking the leader has ended and switching to data reading; this will produce a big block of 1s at the start of the data, because the remaining leader bits are treated as data.

Another thing to watch out for is how you specify a memory block's ending address in a cassette command. If there are less than four hex digits in the ending address, a bug in the ROM will cause the corresponding digits from the starting address to be used, rather than being cleared to zero as they should be. If the corresponding starting-address digits are nonzero, this will cause an unexpectedly long read or write. Thus, when reading a BASIC program, the first block should always be read with 4A.00FFR, not 4A.FFR.

rhester wrote:

Thus far, I have rerecorded the following:

Blackjack (BASIC, LOWMEM=768) [1976].wav
Game of Life (2000.21B7) [1970].wav
Integer BASIC (E000.EFFF) [1976].wav
Little Tower (0300.14CD) [2000].wav
Lunar Lander (0300.09B8) [1976].wav
Microchess (0300.0BC7) [1976].wav
Test Program (0000.000A) [1976].wav

I would be happy to host the completed WAVs on my web site (yet to be published) or even on applefritter if space allows (so far the WAVs vary between a meg and 3.5 megs).

Actually, the re-recorded WAVs should be highly compressible, down to only a few tens of KB. The recorded signal is a pure square wave, with none of the analog variations and distortions that an actual recorded audio signal would have. Thus the recorded WAV has huge amounts of redundancy, perfect for compression.