Problems with replica Apple II Rev. 0

CVT wrote:

Very nice! Since it's a Rev.0, are you planning to add a color killer transistor or the extra color mod?

Those are very much useful mods to get functionality to where the normal later ][ and ][+ models were.  I haven't tried it but I suspect that possibly you wouldn't need to make those mods if you are using one of the A2VGA cards to display to a VGA or HDMI (with adapter) display.

You don't have a "rare Apple ][" though...  you have a reproduction of one, which is currently available.  So no reason not to modify it.  The ][+ is much more useful if you actually want to run software.

WWWD?  (What Would Woz Do?)

He'd modify it!

Macintosh_nik wrote:

I like the way this replica works so far, the bluish tinted letters, the ancient Integer Basic - epitomizing the spirit of the 70's! I'm even thinking later to reduce the DRAM to 3 blocks of 4kb to be more in line with the first Apple II. I'm not a programmer, I don't design maps and such. For me the whole interest is from a historical point of view, to try what computers were like back in the

You need to adjust the color either using the COLOR TRIM capacitor or through the menu of your NTSC monitor. The 4 colors of Rev.0 are supposed to be Black, White, Violet and Green, not Black, White, Blue and Orange as it is showing on the monitor right now.

Macintosh_nik wrote:

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Can you help me with downloading through the cassette input? That's actually much more important to me right now than adjusting the colors on the screen.

With your oscilloscope while loading a program, take a look at what is happening on pin 2 and pin 6 of the op-amp uA741 (after R29):

OpAmp.png

softwarejanitor wrote:

You don't have a "rare Apple ][" though...  you have a reproduction of one, which is currently available.  So no reason not to modify it.  The ][+ is much more useful if you actually want to run software.

 

Should be easily doable with the ROMx or the device he has in the D0 ROM position.  

Other than that, most software written in machine code ought to run satisfactorily, no?  What's holding a Rev-zero back in that regard?

baldrick wrote:

softwarejanitor wrote:

You don't have a "rare Apple ][" though...  you have a reproduction of one, which is currently available.  So no reason not to modify it.  The ][+ is much more useful if you actually want to run software.

 

Should be easily doable with the ROMx or the device he has in the D0 ROM position.  

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The color issue in hires is the one thing that I would fix for sure.  Rev 0 boards have some awful NTSC bugs but if you have a monitor that gives a satisfactory picture then that isn't an immediate issue.

Right - and four colours only is something, too I guess.

Macintosh_nik wrote:

Thanks for your help! I checked uA741 in Apple //e and the Apple_logo file, everything works. I used VLC media player at 100℅ volume, on the Apple II Rev.0 replica it doesn't work, there is no beep saying the download has started. I've added a couple screenshots below that you wanted to see.

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Hmm, everything looks right. You are calling LOAD<Enter> before hitting play, right? Also did you try both the HI-FI and LO-FI versions from https://asciiexpress.net/gameserver/?

baldrick wrote:

Right - and four colours only is something, too I guess.

If you're using a monochrome monitor or not really doing much graphics the four color only thing with Rev 0 probably isn't a big deal either, but for me it is.  It would definitely impact my enjoyment playing a lot of games and even for other graphics.

Macintosh_nik wrote:

I do everything as in this video, on Apple //e it works, on my replica unfortunately not yet. I use the Apple_logo sound file for a reason, because judging by the video it should 100% work on a replica with 48kb of memory. 

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I don't know what to tell you - everything you do seems correct. The only thing I can suggest is to use a very short cable that doesn't go around the TV. Actually it's best if you keep it away from the CRT TV as much as possible. I use a 20 cm shielded AUX cable that I made myself which doesn’t have any extra connections - just a direct jack to jack.

You know I have made two Apple II Rev.0 replica , I will try myself to see if any one of them will work with exactly what you have in your setup, but I would do that on Sunday. 

CVT wrote:

Macintosh_nik wrote:

I do everything as in this video, on Apple //e it works, on my replica unfortunately not yet. I use the Apple_logo sound file for a reason, because judging by the video it should 100% work on a replica with 48kb of memory. 

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I don't know what to tell you - everything you d

Remember how I said Rev 0 machines have issues with NTSC?  Uber sentitvity to cable shielding, length and placement and the monitor being used...  yep.  Later revision motherboards are much less sensitive to any of this.  //e even less so.  This is a lot of why I really hate that Rev 0 clone boards are so popular.  Almost every person who builds one would be much better served by a Rev 7 or later design.  There is seriously no reason at all for most people to start with a Rev 0 motherboard these days because you can't really make an adequate Rev 0 clone due to the availability of parts.  If you are using ROM substitutes, keyboard substitutes and not a Datanetics, don't have a period correct power supply (silver early Astec), case (ventless). etc., then build a clone.  Something like a clone of the Unitron boards that use 2716s instead of 9316 ROMs that are inverted, etc...

But I'm beating a dead horse here because people insist on selling Rev 0 boards and people insist on building them, even though it is vitually guaranteed they''ll run into more issues that way.

The Disk II works with either Integer BASIC or Applesoft BASIC.

The way that Apple DOS works is perhaps surprising: it doesn't use the parser built into BASIC. Instead, the prompt (either Integer BASIC's >, or Applesoft's ] ) is followed by a call to a command reading routine. DOS patches that call so that it is DOS, not BASIC, that reads the following command. DOS interprets the commands it recognizes, and then passes whatever it doesn't recognize back to BASIC. This means that it works equally with Integer or Applesoft.

What is different between the Apple II and Apple II+ is that the original II, in addition to coming with Integer BASIC in ROM, used a Monitor ROM without the autostart feature. So to boot a DOS floppy in the Disk II, you must issue PR#6. The Apple II+, in addition to having Applesoft BASIC in ROM, uses an "Autostart" Monitor ROM, which automatically boots from the highest possible slot when you switch on the computer's power. It first tests slot 7, then slot 6, then slot 5, etc. Because of this, it was customary to put hard disk controllers in slot 7 and the primary floppy controller in slot 6, with any secondary floppy controller in slot 5.

Macintosh_nik wrote:

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It is fundamentally important to me that loading from a cassette tape would work. We do not sell Apple II disk drives, I bought mine in the U.S. but now because of sanctions it is problematic. I would like that other guys in Russia also collected replica Apple II, because there are no expensive or hard to find parts as in Apple -1. Everything can be bought on aliexpress and is cheap, it cost me about 100$ if you don't count the power supply. But without an easy way to download programs, the project loses its appeal.

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Fake TTL chips from AliExpress actually might be the cause of the problem. Very often they take CMOS 74HCT and even 74HC series chips and put a 74LS label on them. They work fine 99% of the time in a purely digital environment, but any time you have an analog-to-digital circuit designed for TTL chips, putting CMOS chips instead is asking for trouble. You can usually tell them apart from their heat signature. Real TTL chips run a lot hotter than CMOS replacements.

One option out of your current predicament is to consider Soviet TTL chips from the late 80s, which are still widely available as NOS and no one in their right mind would consider faking. A friend of mine from the Bulgarian retro-computing forum actually built his own Pravetz 82 (a 1:1 Apple II clone) almost entirely using Soviet chips. He also did it back in the day, while I was probably still in middle school. With his permission I am posting a high resolution picture that he sent me for reference. This has not been posted anywhere else on the Internet.

The only thing to keep in mind is that Soviet chips are metric, so round hole sockets are not ideal for them. Slit sockets are preferred.

Pravetz8SovietChips.JPG

Very nice!!! Contrats!

I'm making a note, never buy chips from aliexpress!! Looks like their logo is a knock off too. 

jeff d wrote:

Very nice!!! Contrats!

I'm making a note, never buy chips from aliexpress!! Looks like their logo is a knock off too. 

Well, that’s not necessarily the lesson to be learned from this. This Apple II Rev.0 replica is still made mostly with AliExpress chips, isn’t it? Actually now that everything is working, it would be super useful if Macintosh_nik posts another picture where all the chips from AliExpress are marked with a dot.

Those 10 were most likely good CMOS chips and there was no need to throw them away. Instead I would have simply put them in a box and label it properly for future projects. For example I got a T.J. Boldt ProDOS ROM card almost entirely made from CMOS 74LS-mislabeled chips from AliExpress and it works perfectly.

Gold in significant amounts is only found in the IC packages made of purple or white ceramic. The lids and the lead frame are gold-plated, and it was even used in the solder (Au80Sn20 and Au98Si2 alloys were used to solder on the lids and attach the silicon die to the carrier).

More common packages don't use much gold as the solder alloy changed, and plating became thinner. Gray ceramic packages with hundreds of pins can contain several grains, simply by the sheer number of plated pins. Additionally, nearly all ICs over 20 years old are wire bonded, in which tiny wires are ultrasonically welded onto pads on the chip and carrier. The bonding wires are often made of gold, although other metals are also common. BGA package technology removes the last reason for gold, as instead of wire bonding, connections are made with solder balls between the die and carrier, or directly between the die and circuit (CSP).

Generally you will see the most gold used in MIL or space-rated components, which already sell for high prices. Economics has squeezed every last trace of gold out of components used in commodity markets. This makes the economic logic of gold recovery from scrap very dicy as in most cases the IC is worth more working than when melted down.

In post #78, 'robespierre' wrote:

"Gold in significant amounts is only found in the IC packages made of purple or white ceramic"

Uncle Bernie clarifies:

Depends on what you consider a "significant" amount. "significant" is just another weasel word. Fact is, most of the gold in ICs is in the gold bond wires, and also in some die bond materials. Any gold seen on pins or within the "purple or white ceramic" packages is just a few atom layers thick. These ICs have about the same gold content per metric ton as medium grade gold ore (high grade: 8-10g/ton, low grade: 1-4g/ton). So the "recycling" to reclaim the gold is worth it. But it's a messy process involving mercury and its toxic vapors and/or cyanides, both a great danger to the environment. Here in Colorado we have a lot of old gold mining ghost towns where nobody wants to live, it's all contaminated, despite the big outfits tried to reclaim the mercury from the amalgamation process (it's also expensive). But some always escapes into the environment. Cynanide leeching in open pits is still being practised here in the state, which has several still operating gold mines. A big environmental hazard.

More modern ICs use copper or aluminum bond wires and these actually are better for long-term reliability. ICs with copper metallization have copper bond pads, and ICs with aluminum metallization have aluminum bond pads. Use the same metal for the bond wire and this connection will not form intermetallic compounds like gold does. So these ICs should live longer if properly stored. This was more widely used from the 1990s up.

So if you collect old ICs in a jar, you may weigh them and run the math how much gold is in it. You probably have more precious metals in your mouth ...

- Uncle Bernie

Yes, 5 beeps means the RAM chip at location C7:

https://github.com/misterblack1/appleII_deadtest?tab=readme-ov-file#interpreting-the-result-display-grid

Macintosh_nik wrote:

Would it make sense for me to try another Apple//e firmware to have a normal menu?

With all the other modifications you've done, why not just add a Lower Case Adapter? You'd have to find something like the original Dan Paymer board or you could opt for something more modern like the Text ROM for ROMX. That would get you 16 different fonts.