Apple II

Weird code in Disk II PROM (bootloader) startup sequence

Submitted by UncleBernie on April 18, 2020 - 8:53pm

I was looking into the PROM P5 that is on the 16 sector / track Disk 2 card.

So far I seem to understand what is going on there, except for this code snippet just at the beginning:

C600 A2 20 A0 00 A2 03

which disassembles to this:

C600 LDX #$20C602 LDY #$00C604 LDX #$03

So when the program is entered at $C600, as some authorative sources claim, the first LDX# does not do anything useful, because X is overwritten by the LDX #$03 before the first X value loaded can do anything else.

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Apple II

Schematics of Saturn 128k board

Submitted by RalfK on April 18, 2020 - 6:49pm

Hi everybody!

I'm looking for schematics of the Saturn 128k board. I've got one (a clone board of the early version), which is not completely populated, and there are some weird details.

TIA, Ralf

 

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Apple II

Beginner book/guide for an Apple II newbies?

Submitted by Fuji on April 18, 2020 - 8:31am

Can anyone recommend a quick, easy and simple newbie (downloadable) book, guide or web page for someone who's interested in getting started with the Apple II but has no prior knowledge or experience with it?

 

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Apple II

Apple IIe Wont Boot, Controller & Drives Working

Submitted by Chris T on April 17, 2020 - 7:20am

Hi, I have an odd issue with an Apple IIe I bought about a month ago. It came with a working Disc II drive, and a Disc II Controller that I was told by the seller that only worked on Channel 1. As a response to this I ended up getting 3 more Disc II controller cards (dont ask). And after using all 3 to trouble shoot each other, I got 3 working fully, and ordered some chips to fix the 4th (not the original).

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Apple II

Monitor /// screen filter

Submitted by Kingpin on April 17, 2020 - 6:07am

Hi!I have a Monitor /// with a screen filter that is dirty. I have tried cleaning it but the dirt (or gunk) is not coming off.Anyone who has experience of removing the filter and cleaning it and (if successful with the cleaning) re-apply it?New filters aren't available anywhere I guess? 

Thanks!

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Apple II

Apple IIe PAL outputting BW video out

Submitted by llopis on April 16, 2020 - 4:10pm

Hi everybody! (First time poster here)

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Apple II

Brazilian Apple IIe back to life after 30 years

Submitted by Time Machine on April 16, 2020 - 9:38am

Hi guys,

After 30 years I decided to turn on my Apple IIe again (actually it’s a Brazilian version called tk3000//e). It looks good, actually it is almost like it was at 80s. It doesn’t have any capacitor leaking and almost no dust.

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Apple II

Apple II game-port 100mA current limit

Submitted by Fuji on April 16, 2020 - 8:56am

According to the Apple II reference manual (page 100) the Apple II game port only allows a current drain of no more than 100 mA.

Many years ago I made a 6 way switchbox which allowed for 6 joystick/paddles etc. to selected simply by rotating a switch (I'll post DIY instructions on how to make one if there's any interest). To indicate which port was in use I connected an LED (in series with a 100 Ohm current limiting resistor) between pin 1 (+5V) and pin 8 (GND) for each port. 

 

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Apple II

Disk Duplication Questions; also Disk Image -> Media?

Submitted by Timelord on April 16, 2020 - 2:10am

I would like to duplicate my master disk sets with the lest fuss. Years ago, I used Copy ][+, v 6.2. Because this was designed for a 128K max system, it always copied DOS 3.3 disks in two sweeps. I try to read and write from the best-aligned drive mechanism,  so the least disk swapping, the better. 

 

I'm curious what disk copying software recognises expanded memory, and can do this in a single sweep. Being able to read a disk into RAM and write that out twice would also be handy, for creating two sets of system master disks. 

 

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Apple II

Disk ][ Analogue Board Trimmers

Submitted by Timelord on April 16, 2020 - 1:23am

On the Disk ][ Analogue Board (691-92001), there are two trimmers, factory set and sealed with orange/yellow wax. On one of the drives that I have, one of these has been broken free. 

 

The service books do not and never have mentioned adjusting these. Does anyone recall what each trimmer does, and how to calibrate them?

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