Apple 1 Replica Bootup/Display Problem.

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Apple 1 Replica Bootup/Display Problem.

Hi All,

Ive been trying to get my Apple 1 replica up and running. But i'm abit unsure how to fix this issue with my apple,

the screen turns on and displays dashes but there is no sign of any cpu bootup or any prompt.

When i press CLEAR it clears the screen but then goes back to the dashes again. Also RESET does nothing.

Thanks for your time.

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First of all, I see a few

First of all, I see a few things going on here, before we can proceed in troubleshooting...

 

First, I hope you are going to put a heat sink on the LM323K....

 

Second, your "boot up" screen is "wrong.  I think you most likely have a bad 2504V shift register.

 

As for the reset "bouncing", do you have access to a logic analyzer or capturing oscilloscope?  I would eliminate that it is a mechaanical problem with the reset signal from the keyboard "bouncing".  While it looks like it's a leaf type keyboard you have there, it still could have issues.  If you had a datanetics, it would be an 80% change it was a reset switch.  Next I would check the wiriing and your cable.  Make sure it has a solid connection not intermittent.  Also grab a maginifing glass so you can look over the back of your board for poor solder joints.  

 

Once you have done the above post back and we can do some deeper troubleshooting.

 

Cheers,

Corey

 

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Update

Just abit of an update.

I've ordered new 2504v's, also i have the heatsink for the lm323k but im waiting for the mounting kit to arrive.

I will post an update when the parts arrive.

 

Thanks For The Help.

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Same thing here, I could get

Same thing here, I could get the normal "_@" flashing screen but when I press reset, it gave the same screen full of stationery "-" signs. The keyboard adapter connections are correct. It just cannot be reset even though the 6502 pin 40 voltage is pulled low during reset press.

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@spectra208,   any progress

@spectra208,   any progress on what I mentioned?

 

@appehpman, please start a separate thread describing your issue and a picture of your board and setup. This will help us not mix spectra’s and your issues which may not be related.   Also double check your solder connections on the reverse side and that all chips are seated correctly without any bend under pins.  Then we can help you troubleshoot your issue. 

 

Cheers,

Corey

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Progress

@Cory986,

I have replaced all of the 2504v's and nothing changed, but i have noticed the 2519b is not working.

I am now waiting for another 2519b to arrive.

 

Thanks.

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Update

UPDATE:

I have replaced All 2504v's

I have replaced the 2519b.

And Its Still The Same.

Thanks.

 

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OK a few questions... Have

OK a few questions... Have you tried bringing up just the video section?  Do you have access to an oscilloscope and know how to use it?

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@Corey986,

@Corey986,

I have tried bringing up the video section and it's still the same.

Also i do have an oscilloscope.

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Apple 1 Replica Dispaly Problem

Hello,

 

I have the same problem (similar screen, I think). This is the screen, and I only populate the video section (no keyboard or others components). 

I used  a 3021N chip instead the 2513 (but I think is totally compatible).

I hope someone can help us. Thanks

 

Evandro

Brazil

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Ok before we dig into both

Ok before we dig into both your issues to see if they are the same.  

 

Are both of you using Newton boards?   And when did you get them?  Let’s try to eliminate that it could be a bad run of boards.  

 

I’ll also take a look at the schematics later and try to think though what this could be.    I’ll also try to depopulate one of my Mimeos to the video section only so I can scope around and give you some ideas to look.  

 

 

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@Cory986 my apple board is a

@Cory986 my apple board is a newton board. I got mine in 2013 but it's copyrighted 2012 the model number is ac1 200a

 

 

 

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Hello,

Hello,

 

Mine is the same. Newton NTI from 2012.

I bought a new 2513 Character ROM (the same that comes with the kit) and I´ll receive until Friday.

Thanks for your help

Evandro

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Hello, I attached two

Hello, I attached two pictures of my board.  Thanks

 

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Hello guys, good news.

Hello guys, good news.

I changed the 2513 - Character ROM and now is working a little better. When I boot up, I get this screen with the @ blinking. 

 

I have these " [ " in some positions, and now I´ll investigate what is this.

 

 

When I clear up the screen (shorting pin 12 and +5V), I can see only the @ blinking. 

I don´t have a keyboard yet, so I can´t test the others functions. If I have news about the " [ " I´ll send here.

Thanks all

 

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That looks correct....

That looks correct....

 

If the CPU section is populated, you should be able to do a similar trick to ground for the processor reset line (pin 1 to pin 9) after you clear the screen.  You should see the \ prompt.  If not then start looking at the PIA as the most common issue.  If the RAM is bad, things generally won't work once you start typing...

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Good News Again

Hello!

 

I did new tests, and I realized that changing the 2504V each other, the problem with the " [ " changes too.

So I was changing every 2504V with a new that I had in stock, and now, everything is fine! 

The next step is populate the CPU section, and I´ll do next few days.

Thanks Corey986 to help us in this problem

 

Evandro

Brazil

 

 

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So The Problem Is The 2513?

So The Problem Is The 2513?

Is There A Way To Test The Character Rom?

Because I Want To Test The Rom Before Buying Another One.

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I don´t think so

Hello Spectra208,

In my case, changing the 2513 (and one 2504V) solve the problem. 

I don´t know how to test this component, and I think it´s not possible, because it´s a ROM.

 

I bought a new one in Brazil and paid about U$35+shipping (is new and in a good shape - year 1982!). 

If you need one, I can verify with the seller if he could send to your country. Thanks

 

Evandro

 

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Problems with Video

Hello Everyone,

 

I am building the Apple 1 kit and need help.  Checked all soldering and power supply.  Did not populate the CPU section since I cannot get past the display driver starting up.   Swapped around 2504 shift registers and no luck.  The scope screenshot is from the video out pins.

 

Help!!

 

 

 

 

 

 

 

 

 

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Video

Hi eackerman,  my suggestions are for the Mimeo board but should help.  You may want to start a new topic and describe your setup and what you have done todate in detail.

Remove all the chips from rows A and B.  Remove  D2 (2513), C3 (2519) and D4a, D4b, D5a, D5b, D14a, D14b and C11b (2504).   

Power on.
1) Video section displays 40 x 24 fixed "█" symbols (with no 25xx parts present)
2) Video section displays 40 x 24 fixed "@" symbols (with only 2513 present)
3) Video section displays 40 x 24 flashing "@" symbols (with 2513 and 2519 present)
4) Video section displays full screen of flashing "_@" symbols (with all 25xx parts present) and can be cleared with CLR line

 

Once you reach step 4, use your scope to observe pins 1 and 5.  They should be very similar.

 

Once the videop is working properly, then populate rows A abd B.

 

Good luck.

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