Apple II

Apple II Europlus scrambled display

Submitted by td75 on June 28, 2019 - 9:23am

Hi everyone,

I'm new to this great forum and was hoping to get some help on getting an Apple II Europlus working that I recently aquired.

It initially did not turn on at all so stripped down power supply and after replacing damaged capacitors, bridge rectifier and fuse, I now have power.

When I turn it on there is no beep but there is just a scrambled display as shown in image.

It looks like there has already been some work done on this motherboard previously as there is a machine pinned IC socket used for the 6502 CPU.

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Apple II

Apple ii+ Stuck Screen Characters

Submitted by Pugy3658 on June 26, 2019 - 6:51am

I recently purchased an Apple ][ Plus system. I have wanted one for a long time and finally saw one for a a decent price, knowing it had some issues. In the listing the seller said he couldn’t get it to display a stable image on a screen at all.

 

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Apple II

Apple II only sees 1st 32K

Submitted by Kingpin on June 22, 2019 - 10:06am

I have a couple of issues with an Apple II+ that I got recently. As I don't have any good documentation on it and I found this forum I thought I'd give it shot here.

 

When running Apple II Confidence program I only see/can test the 1st 32K of memory (the last 16K between 32 and 48K isn't visible). The 1st 32K checks out without any issues through several passes so clearly something with the last 16K. If it was RAM chip(s) that was the issue I would have assumed that I would have seen the full 48K and that the RAM test would have nailed it down to the correct RAM chip(s).

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Apple II

Weird Capacitor in Monitor //c

Submitted by TobyJennings on June 18, 2019 - 7:41pm

I'm try to repair/refurbish a Monitor //c and there's this weird capacitor that I can't find a replacement for.

 

C515 is a "4 uF 25V NP" cap. I can't find any such animal. Is there another cap I can safely use? 

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Apple II

What is this Apple II Keyboard?

Submitted by robert29b on June 16, 2019 - 12:47am

A while ago I bought this Apple II Keyboard from someone in th UK.  It was in a Datanetics box along with other "spare parts."  It has apparently never been used and is in excellent shape.  The keys are crisp with a sharp actuation - unlike all the other heavily used, mushy A2 keyboards I have.  It looks like a regular early Apple II keyboard, except the keys are black.  Is it from an Apple II Europlus?  An ITT 2020?  It is marked Apple Computer Inc., ASSY NO 01-0425, made in USA 1979.

 

Anyone have an info on it?

 

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Apple II

Custom character set?

Submitted by gmontag451 on June 14, 2019 - 4:52pm

Am I correct in my conclusion that there isn't an easy way of creating a custom character set for the Apple II? I've Googled around and can't really find any info on this.

 

Coming from the Commodore 64, I assumed it was as common on the Apple II. Google reveals replacement ROMs, as well as type-in programs like COMPUTE!'s SuperFont which seem to utilize the HGR mode to provide custom characters. (Conversely, it also appears that it isn't easy to put text on the HGR screen, but there are several websites which cover that topic.)

 

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Apple II

Apple ][+ no graphics mode

Submitted by Signal64 on June 14, 2019 - 4:26pm

Hello All,

 

I'm trying to revive a Rev D RFI Apple ][+ board and running into an issue.

I can't get it to flip into either lores or hires graphics mode.

 

HGR command just returns to a viewable prompt and GR will display text garbage (where graphics is expected) with the normal viewable prompt and text lines at the bottom.

I can switch back to TEXT mode fine.

 

Going through W. Gayler's "The Apple II Circuit Description" (Chapter 8) the 74LS151 at A9 seems to handle the soft switches.

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Apple II

Dram Memory Tester. Anybody use the following?

Submitted by NovellNetware on June 13, 2019 - 10:00pm

When I first started working on computer we had a dram tester. Simple little box with a button for testing and a knob for speed. Lock in the chip to set the speed and hit the buttons. Simple red / green light tells if it passed or not. I found out by pushing the speed up a tad more. It weeded out bad or questionable chips. Luckly this was at the time dram was cheap due to being replaced with simms. I'm looking around just in case I need one to trouble shoot the ram in my Apple II+ When I get it. I found this on e-bay.

 

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Apple II

The Fun Of Old Your First Computer and other Books.

Submitted by NovellNetware on June 11, 2019 - 9:15pm

One of things I did was collect a very small amount of vintage computer books. For example the on in the Title. Your First Computer. We are talking 1976-(say) 1985 books or so. The book I was looking at the other day had an apple II in it. I never paid attention. I always thought it was a 2 plus. It is one of the later Apple II since it has air vents in the side. But the book and the picture explained it was just an apple II.

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Apple II

PSU Recap Question on Values

Submitted by KLund1 on June 10, 2019 - 9:13pm

Hi all,

  I just received a recap kit from Console5.com. A very good site for such items! I ordered the kit for the model AIIe I have, AA11040-B.

I started to remove caps, and noticed the replacement caps values are different. I am not a EE person and do know too much about what the values mean. I have read you should replace caps with same or better.

The large caps on the high side show 100uf 250v. The replacement caps is about 1/2 the size and shows 47uf 250V. Can I use these?

Just want to verify.

Thanks

 

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