Apple II

Problems with replica Apple II Rev. 0

Hey guys!!! I got my project to create a replica of Apple II Rev. 0. Briefly what I used: power supply RQ-65B, board from the project of the respected Mike Willegal, Apple II +ROM board replacement, all components except what I have left after the assembly of the replica Apple-1 I bought on Aliexpress. I know it's not the best option, but now for me because of the imbargo only such conditions, there are no others.

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Troubleshooting disk drive issue

I have an Apple IIe that has stopped reading disks.  I was loading various disks that I had lying around to see what was on them and the system just stopped loading anything off the disk drive (duodisk).   

Here is the steps I have taken so far:

I examined the analog board but could see no obvious issues

I swapped out the duodrive for another duodrive and I am getting the same issue.

I also tried 3 different unidisks and one worked once but then stopped loading again

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Troubleshooting Apple II Plus -- System Board or Power Supply?

Hello,

 

When I turn on my Apple II Plus, the system doesn't boot and the power supply makes a rapid ticking noise.  When I disconnect the power supply, I can read the correct voltages on the Power Supply connector.  At this point, I am unsure as to whether the power supply isn't putting out the proper current or there is a problem on the system board.

 

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Construction of my Apple II Rev. 0 Replica.

 

 

(Sorry for my writing, but I use a translator)

 

Following the instructions of http://www.willegal.net/appleii/appleii-first_page.htm I have mounted my own Apple II Rev 0.

It would not have been possible without the help of good friends.

It is not finished yet, but it is already functional.

When I started this project I barely knew how to weld. My electronics knowledge are very low if no saying.

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Apple II Plus Power Supply Weirdness??

As I posted in a another thread, I just purchased an Apple II Plus for a great price.  However, the power supply was DOA.  There was no power coming from any of the pins.  Since I don't know anything about Apple II power supplies but what I posted, I spent some time trying to diagnose the problem and couldn't find anything other than it had no output.  I did read around a 320 volt voltage near the big honking transistor.  But, otherwise, there was nothing.

 

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Mystery Part in Apple II Plus

Hello,

 

I am new to Apple II's and, recently, purchased an Apple II Plus off of ebay for a great price.  There was no guarantee of it working, but, that's ok.  It had 3 cards and the price was good.   :-)

 

Inside the case, I found a mystery part and it looks like the picture below.  I've been keeping my eyes open to try to figure out what it is.  Now, I've found another one jammed under the keyboard.  My thought is that it doesn't belong and a kid decided to put his toys in the computer.  But, I am unsure.

 

Does this look familiar?

 

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Using SRAM for an Apple II

I just read UncleBernie's response here:  https://www.applefritter.com/content/let-me-introduce-myself 

 

So, I figured the timing was right to discuss the issue of SRAM write timing on an Apple II.

 

What I believe that UncleBernie is describing is a problem whereby if you synchronize the write with the fall of Phi2 that it is too late.  The address and/or data is now corrupted, on the busses, and the data written will be bad.  There is a similar problem, on Atari computers, due to the buffering of Phi2.  I am also thinking the data bus corruption issue may be made worse because after Phi2 falls, the address and data busses are now used by the video subsystem so the additional hold time of the CPU is effectively eliminated.

 

I was looking into using SRAM and was thinking that it may be possible to use SRAM if the SRAM's write enable signal is high on read and low when the CPU R/W is low and /CAS is low.  This would result in the SRAM write enable going high when /CAS goes high...which should result in the data being written before Phi2 falls and the busses are corrupted.

 

This chart shows why you wouldn't want to use Phi0 or Phi2 to synchronize the write timing:

 

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Disk II Application Note: Anyone here purchase this item from ebay? I'm interested in some of the "extras"

A few weeks back there was a listing on ebay for basically the Apple II Redbook, but along with those are some extra "paperwork".

The extras seem to include things like at least a monitor schematic, circuits analysis, and some other intersting paperwork.

 

I'm wondering if someone here was the high bidder, and if so... would you share scans of the other stuff?  Please... =)

 

ORIGINAL Apple II Red Book Reference Manual 1978 PLUS EXTRA PAPERWORK

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Let me introduce myself

Hi,

I started an initiative few years ago to teach ourselves about computers, it was called msxmakers because was initially focused on msx.

our project try to teach ourselves how to build new hardware.

So, my idea is not focus on repairing old hardware but build it, some times using as older chips as Woz, sometimes adding new chips as long as we can study them and understand it, but new pcb designs and with gpl schematics when possible.

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Monitor recaps: Need parts lists

So I have three green phosper displays that need a recap.  The first is an Amdek 300, the second is an Apple Monior ///, and the last is a Kaga KG-12NU.  I also have an Apple Monitor II (the one with a tilt screen) that will fliker initilly, if left idle for an extended period, but stabolizes after a while.

Additionally, I have a Color/Composite Apple //c monitor that needs a recap as well.  Console5 has a kit for the //e model, but I don't know if that translates to the //c.

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