Apple 1 ram banks

Maxplayz

How does it not? I am showing you why i cant clear the screen when i press the button on my ps/2 keyboard adapter

Because your terminal section is not working, likely the 2804 or 2519.

Maxplayz

Also i bought a pack of 7x AM2804PC from the apple 1 replica website

Which web site? you are talking about?

If you are talking about Armin Hierstetters page https://www.apple-1-replica.com/shop, we can indeed assume they are working.

But how should we know this, when you don't tell us?

If the 2519 also from there if not that is the most likely next candidate.

But this are decades old chips they can die any time even if they have been testes good before chipment.

ESD while handling could be a cause.

We need some measuremts to tell you what to do.

Maxplayz wrote:

my assumption is its most likely due to the lack of ram. I only have 3 RAM ICs installed at the moment

How often do we need to repeat? your assumption is wrong!

Not only I also peo2000 told you:

The terminal section is definitely not working.

And before that, it doesn't make sense to discuss any memory/RAM/ROM mappings or substitutions.

I would first rip out the entire CPU section (except B2), and on the top half everything on 2513/2519/2504, checking them step by step.

Without 2513/2519/7x2504, there should be an "endless carpet" of non-blinking "█".

With the 2513, the "carpet" should be non-blinking "@", as shown in the above post.

Then with 2519, there should actually be a 40x24 "frame" of blinking "@"s, which you can temporarily blank with Clear Screen.

After that, they should continue blinking.

If you now plug in a 2504 on C11B, you would be able to permanently delete the blinking content with Clear Screen, and only a single @ would blink.

...I would try to achieve this first...

CPU section is row A and B.

Even with only B2 installed in this two rows you will get blinking and Clear screen to work, if all parts are working in Rows C and D.

In the citate of peo2000 above you find further hints to diagnose also check out the rest of this thread and answer question or accept that you spend a lot of money for a pile of junk you can not get working.

Then you should better try something else and find someone with another replica who can confirm that.

What about the DS0025? that drives the 2804?

Why is it so hard with you, to get any useful info into this thread?

If everything would be as you describe your Apple I would be running perfectly and you would not ask for help.

Everything soldered perfectly, all parts are good...

On the other hand no measurements, barely no answers, no nothing.

One of the first questions was: where did you get the parts from? After 2 pages of posts this question is still only half answered.

If you have no idea about electronics why did you start to build one of the most horrible designed computers from today's perspective?

Half of the parts are long obsolete, sourcing them is a nightmare. Even if build correctly there are very high chances that it will not run, at least not reliable. Uncle Bernie proposed about a dozen of modifications to fix that. Some of the parts need to be adjusted through either measurements and calculations or trial and error.

Why not build an Apple I Clone that does not have all this problems? There are enough warnings around, that say buy a complete tested kit or don't do it, if you don't have a clue what you do.

Maybe it's best you box everything and send it to someone with a clue. You said you are from UK, maybe https://www.menditmark.com/menditlikemark62342123

https://www.perton-electronics.co.uk/index.html can help you.

You expect an answer change part XYZ and fixed, but that is not how electrics works. With that extreme low level of cooperation and the practically non-existent willingness to disclose necessary data, there is no hope of getting the Apple I to work.

We can't read your mind, we don't have the X-ray view and we also don't have a fortune-telling crystal ball.

To move forward we need some oscilloscope measurements, or Logic Analyzer plots.

We still don't know what equipment you have got (asked at least twice) we can't explain you anything if you don't answer the question.

If you are pissed now because of this answer that will happen everywhere if you act alike here.

Mark for sure can if he finds time.

But to rob your imaginations he will not do that for free.

This guy is also from UK https://youtube.com/@hammyarcade and has the skills to get that thing working.

And everyone else here needs the same info I am begging you for.

Like how you behave it is unlikely you find some one with more patience or is even willing to help.

If you want to learn about apple I start here: https://www.sbprojects.net/projects/apple1/index.php

Terminal part:

https://www.sbprojects.net/projects/apple1/terminal.php

Nope!

Your 2513 seems to be working (at least somewhat) well.  That's the only thing I can tell from your sparse information, by the way.

Your shift register(s) aren't working, most likely your 2519.

So I'd take care of that first...

If the 2513 would not work you would see either dark or light boxes but no @ signs.

Why is maxplayz completely ignoring us if he wants help and always comes up with another "strange" idea?

So my guess was right, I did mention a couple of times that the DS0025 can case all Shifregisters to fail.

But with close to zero information hard to tell.

Measurements would have helped a lot.

We might have been able to talk you through if you would have given more details about your equipment.

Even if you don't know the Oscilloscope we need to know the exact type the firmware to find a fitting manual.

As it is not a classic CRT one the setup is model specific.

Most questions are unanswered and there are no request to explain certain questions.

And the Apple 1 is about the worst kit someone with basic electric knowledge can build.

So do you get an alternating Pattern now?

Is the @ blinking?

You are talking about 30-50 year old parts it's not uncommon when they arrive in none working conditions when they have not been tested for function before shipment. Even that just reduces the dead on arrival risk but does not eliminate it. The production of that parts was stopped latest in the 90s.

That is why it is so important to know if it's a apple I component specialized seller who sends out tested components, a general reliable seller or marketplace seller or a chinese seller.

It's not to find out which secret source you discovered.

With the Arduino nano I mentioned before you can build cheap testing tools.

I don't beleave that result.

What kind of IC tester are you using?

The tester does not seem to be able to test the 74166 correctly they are all working other wise you would not see the @ signs.

74157 at C4 can be a cause why you only see @ but no alternating @_ likely identified correctly as C14 is also a 74157 and was identified as good.

74174 at C7 can be a cause when the Carriage Return Circuit is not working.

You see these are information we can work with, get atleast a new 74157 and 74174. 

Did you use a TSH-06F Tester? https://goldenchipset.com/24download/TSH-06F_Manual.pdf

Did you set it to 5.0V mode? and not to Auto.

Did you set it to 74LS? or 74HC? the first would be most correct.

Autodetection fails in many cases on this device manual selection is far more secure.

Maxplayz wrote:

I used my T48 mini which has a logic gate tester built in

As the Software gives some detailed info can you please retest the 74161 and create a screenshot of the result.

Do all 3 give the exact same result?

It's still unlikely they are broken if you got a stable picture with @-signs as this chips are the conters that generate the video raster.

As they are unexpensive get a couple of spares.

I have an idea what could be the issue with this chip https://www.silicon-ark.co.uk/datasheets/74ls161an-datasheet-signetics.pdf

It could be the case the chips have a fake printing, and they are close relatives.

It would be interesting if they test positive as 74160, 74162 or 74163.

I would only expect a 74163 to work as a replacement.

Something that makes a ddifference on the Apple 1 Position IC D8 needs to be a 74161 not  a 74161A because there are open inputs and A-type chips are more sensitive to areal noise and will produce random results. 

You shouldn't necessarily trust the TTL test results of the Minipro/TL866/T48/etc.

I know for sure that the test vectors for the 74161, for example, are incorrect.

My TL866 also reported all 74161s as defective, even though they work perfectly.

If you want more reliable test results, you'll have to use something like a Retro Chip Tester Pro... :-)

peo2000 wrote:

You shouldn't necessarily trust the TTL test results of the Minipro/TL866/T48/etc.

I know for sure that the test vectors for the 74161, for example, are incorrect.

My TL866 also reported all 74161s as defective, even though they work perfectly.

If you want more reliable test results, you'll have to use something like a Retro Chip Tester Pro... :-)

Good to know it's actually broken.

I don't get you.

sn5400n at c15 good

7400 at B1 good

You listed both 7400 (B1 and C15) as good and did not list any 7400 as bad.

So I guess you are talking about D10?

D10 in charge for the vertical blanking, what seems to work we see an upper and lower border and two more gates are used for begin of line detection and loading a new character into the serializer what works as well.

So I doubt that the 7400 at position D10 was faulty.

What about these chips:

74157 at C4 can be a cause why you only see @ but no alternating @_ likely identified correctly as C14 is also a 74157 and was identified as good.

74174 at C7 can be a cause when the Carriage Return Circuit is not working.

Did you change them? Did it change something?

It's nice that you know what you did, but if we don't know what has been done, it's impossible to help you!

Even if your tester told you C4 is bad it looks like it is working fine as you have an upper and lower border and CLEAR works temporal.

You could exchange both 74157 C4 and C14 and see if that changes the behavier if you not already replaced the bad 74157 with a good tested one.