Apple Replica - 555 Astable Circuit

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Apple Replica - 555 Astable Circuit

I'm slowly checking my Apple 1 Replica trying to get the video working, i.e. populated Row's D, C and B2.

Waiting for parts coming to Australia, means I have time :-)

I checked the timing of the 555 Cursor timing, theoretic time period is 457 msec, and mine is 544 msec.

Is this Time Period acceptable, and how about the noise level?  Thank you :-)
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Any cursor blink rate is fine - don't worry about the 555.

In post #1, 'RusselSpeight1967' wrote"

 

" Is this Time Period acceptable, and how about the noise level ?  Thank you :-) "

 

Uncle Bernie answers:

 

Any frequency of cursor blink   y o u   find acceptable for yourself is fine.  The cursor blink frequency of the Apple-1 is all over the place, due to the tolerances of of the 22uF electrolytic capacitor and the two 10 kOhm resistors.

 

Noise level - the noise level of the digital logic switching spikes in any Apple-1 always looks frightening, as there is no "solid ground" anywhere in the machine.

 

This is due to the PCB layout with the pathetically narrow power and ground rails, and too few bypass capacitors on these rails.

 

This can be mitigated by adding my 'reliability mods' you can find elsewhere in this forum. But don't put them in unless the machine doesn't work.

 

Still not sure if you mean a 'clone' (based on the original schematic and the original IC types) or a 'replica' such as Vince Briel's Replica-1 which uses more modern components. This confusion of the term 'clone' and 'replica' has plagued the Apple-1 one world since Vince Briel's solution came out.

 

Historically,  the computer world got it backwards by calling knockoffs of the Apple II or the IBM PC 'clones', which in the strict (biological) definition of the word is wrong. A 'clone' is genetically identical to the organism it was cloned from. And hence, not only looks exactly the same, but also functions the same on a  bio-chemistry level. While a 'replica' is a more or less faithful reproduction of a man-made thing which may use different materials and techniques of construction.

 

It would be helpful if we call the Apple-1-ish things built with the original circuit designed by Woz on any of the reproduction PCBs 'clones' to differentiate them from Vince Briel's designs.

 

- Uncle Bernie

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I don’t think there is any

I don’t think there is any confusion. Vince Briel’s "Replica 1" is a clone, according to Wikipedia: https://en.wikipedia.org/wiki/Replica_1

 

Simply naming it “Replica 1”, doesn’t mean it’s an actual replica, just like the name “Apple 1” doesn’t mean it’s an actual apple.

 

Based on the title of this post, I am assuming the author is asking about Woz’s Apple 1 design and his motherboard looks more or less like this: https://en.wikipedia.org/wiki/Apple_I

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Fruitless haggling over the words 'clone' and 'replica' again.

In post #3. CVT wrote:

 

" Vince Briel’s "Replica 1" is a clone, according to Wikipedia .. "

 

Uncle Bernie objects:

 

Wikipedia is not the guardian of the truth. There is a lot of cr@p on Wikipedia, and the truth is often purged by the censors. Orwellian "1984" methods are rooted in destroying the meaning of words, banning words, and to make words disappear. Unperson. Unword. Newspeak.  But this is not the topic here. Just saying that Wikipedia is not a reliable source of information - for anything. If you want to understand the meaning of a word, you have to look up OLD dictionaries which were printed before the communists / leftists / bolshevists started to mess with them: "if you want to destroy a nation, destroy their language".

 

As I have explained in my post #2, the misuse of the word 'clone' in the computer space started in the late 1970s/early1980. They never should have used it for knockoffs of the Apple II or the IBM PC. But they did. So not the word 'clone' is worthless because it became ambiguous. Which leads to confusion. Such as with Vince Briel's "Replica 1" being confused with the Apple-1 copies. You see - I don't insist on the use of the word 'clone'. A "copy" is a word that still has the right meaning.

 

If we wanted to be nit-picking then the use of the word 'clone' for  a man-made object should be severely punished, like in school, the pupil gets a "F" for FAIL" and must stay and write 100 times "a clone is a living organism with the same genetic code as the parent organism".

 

Still this would not be helpful to avoid confusion with what somebody actually did build: a Vince Briel "Replica 1" or a "Apple 1 copy" or "Apple 1 clone".

 

As a footnote, the English language is a total mess because of the misuse of words, diluting their meaning, going on since the Dark Ages, so the (printed) "Webster's Encyclopedic Unabridged Dictionary of the English Language" I have (and trust) lists over 250000 words, and lots of them have so many different meanings they are nowadays all but useless to write concise scientific papers which are not ambiguous. There is a lot of bloat in such texts because added explanations are needed to mitigate the ambiguities of the English words. Other languages are much more concise.

 

As a general rule, imprecise and ambiguous language leads to imprecise and ambiguous thinking leads to imprecise and ambiguous results.

English is one of the worst languages in this respect.

 

- Uncle Bernie

 

 

 

 

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Trying to swap the meanings

Trying to swap the meanings of two well established terms of a language that has more than a billion speakers is an exercise in futility (on par with trying to list all the real numbers between 0 and 1), nevertheless it's a lot of fun to watch someone try! :)

 

What you need to understand is that some words change their meaning over time as languages evolve. "Computer" for example used to be a profession that a lot of women in the 50s had.

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On my jousting against the "clone" vs. "replica" windmills ...

In post #5, JVC wrote:

 

" Trying to swap the meanings of two well established terms of a language that has more than a billion speakers is an exercise in futility (on par with trying to list all the real numbers between 0 and 1), nevertheless it's a lot of fun to watch someone try! :) "

 

 

Uncle Bernie says:

 

Oh, this is what bugs you. Me having the  audacity   to try change the use of the word "clone" for a billion speakers of the English language.

 

You are mistaken !

 

All I seek is to stop the permanent confusion in the Apple-1 world between the Apple-1 copies and the Briel "Replica 1".

 

This is why I'm jousting against the "clone" vs. "replica" windmills whenever the opportunity arises.

 

If that would lead to a more exact language in the various posts here in the Applefritter Apple-1 forum, I'd have achieved everything I wanted  from that !

 

If you, CVT, have fun with observing my (so far: futile) attempts, fair enough ! Have your fun !

 

I'm not interested in changing the (mis)use of the word "clone" anywhere else. It has no purpose to even try.

 

But here in the Apple-1 forum it would help   a   lot   to avoid the frequent confusion of Apple-1 copies with the "Replica 1".

 

Maybe we should blame Vince Briel for that. He should have found a less confusing name for his "Replica 1".

 

I'm currently stuck with calling my Apple IIe substitute "Replica 2e" just to follow the precedent set by Vince.

 

Because if we agree /assume that his "Replica 1" was so named with a reason, any  thing  which substitutes the real Apple IIe circuitry with something totally different may be called "Replica 2e" for the same reason. Of course, I will refuse to call it a "clone" !

 

Just trying to make sense. Do I ?

 

(Oh, and I'm obviously not creative enough to find a better name for my "Replica 2e". I'm just following the precedent set by Vince.)

 

- Uncle Bernie

  

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Hi All,I have an original

Hi All,I have an original working Apple 2E from 1984, an building an Apple1.  I wanted to be clear that I'm using a modern reproduction Apple 1 mainboard.  I'm sourcing the components myself and going through a huge learning curve and finding all the advice on this forum great.  From me, experiencing the issues faced by users back in the 1970's is a valuable experience.

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RussellSpeight1967 wrote:Hi
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RussellSpeight1967 wrote

I'm not removing any of the Apple 2e components, to test on Apple 1 :-)

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UncleBernie wrote:...Because
UncleBernie wrote:

...

Because if we agree /assume that his "Replica 1" was so named with a reason, any  thing  which substitutes the real Apple IIe circuitry with something totally different may be called "Replica 2e" for the same reason. Of course, I will refuse to call it a "clone" !

...

 

We can definitely agree that both "Replica 1" and "Replica 2e" are great names. However people will call your "Replica 2e" an Apple II clone when it comes out, so you would be wise to accept that and concentrate on the work instead. Actually you don't have to wait to see that I am right about this, because it sort of already happened 8 years agohttp://forum.6502.org/viewtopic.php?f=3&t=3656

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Hi guys!

The guy needs help with repairing his board, maybe he can concentrate on that for the moment? And we can put disputes on terminology in a separate topic, if anyone needs it.

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Hi RussellSpeight1967!

I think you should get rid of all LS chips now, they don't belong there. And check the soldering thoroughly, after that we can move on.

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Hi RussellSpeight1967!

The 74LS157 should definitely be removed, here is what I found and translated for you. 

 

"74157 should not be replaced by 1533KP11 or 74LS157 ! Especially memory multiplexers, because they can not cope with the load (16 inputs MS RAM).

At such replacement the memory will start to glitch, write and read will not always be written and read, information in the RAM will fall"

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Well tonight I made good

Well tonight I made good progress.I have now progressed and have a screen of flashing "@".I replaced the logic chips, with some modern versions, and found the 74LS08 in C12 was corrupt, this was from ICs that I brought with me from the UK in 1995.

Then I could replace the 2504 in D4, D5, D14, the screen was very cler and still flashing.Then when I added the 2504 in C11B the screen scrolled to the top of the screen.I numbered all the 2504 using small pieces of post it notes, and am confient the 2504s all workSo now I have to track down this problem.Good progress today.I good 74 Series logic analyser is on my shopping list.

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I am waiting for 74161 to

I am waiting for 74161 to come from Sydney.Ok, I will make a certified effort to get 74 ICs and not 74LS.And now have a nice magnifier so can check my poor soldering.

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I replaced the 2504 in C11B,

I replaced the 2504 in C11B, and removed D4A.The cursor is working, and I have partial screen with cursor flashing.  Incorrect charaters.My 7 x 2504 are Ok.When all 7 x 2504 are installed then the screen scrolls up.Thinking:- A soldering fault on the main board, or- Some of the LS logic ICs are causing problems.I need a supplier who know has the vintage chips.

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Hi RussellSpeight1967!

Wrong characters? Sometimes and just bad 2504 gives wrong characters on the screen. Read this thread, I've added many pics there. 

 

https://www.applefritter.com/content/horror-room-symptoms-bad-cis

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I have a similar horror

I have a similar horror graveyard of Arduino board have I have killed over the years :-)

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Today I populated the main

Today I populated the main board with all ICs.

Had to use LS logic ICs, need to source original 74 ICs.  This maybe the cause of my problems.

Still waiting for 74161 to come, beginning to think seller was not legitimate.Only populated one bank of DRAM, have not added "E to W" jumper wire yet.

No ICs were running hot, good news.With All x 7 2405  ICs installed the screen scrolled up, which was the same behaviour as before the board was fully populated.With 6 x 2504 and C11B removed the screen was showing "Flashing @"With 6 x 2504 and D4B revoved the screen scrolled up and stopped at top 5 rows.

74123 Pin 2 signal looked good74123 Pin 13 signal looked good, adjusted to 480 nsec, using trimmer resistor

74125 Pin 15 looked good

6502 pin 36/37 were also good.Posted Photos on Google Drive: Photos

 

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Slightly off-topic: damn that

Slightly off-topic: damn that case light bulb you are having there, for nightly inspections, I love it!

Does remember me of my Fiat 850 from 1968, when you opened the back (the engine compartment) a light turned on automatically. At least when the contacts were not rusty.

 

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