Help using/fixing Apple // europlus

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Circuit cuts and crystal frequencies
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Very interesting thanks! So

Very interesting thanks! So the Europlus is 100% black and white even with an NTSC monitor. Cheers!

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My understanding is that to

My understanding is that to get color you need a PAL card and I think it needs to go in slot 7.

 

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indeed. I thought that it

indeed. I thought that it would display proper NTSC out of the box but no so that's good to know.

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tony359 wrote:indeed. I
tony359 wrote:

indeed. I thought that it would display proper NTSC out of the box but no so that's good to know.

There are a bunch of mods that were done to the NTSC boards to make them generate PAL timings.  It is my understanding that if these mods are done it can't generate NTSC color any more.  Supposedly it is possible to reverse those mods. But frankly I wouldn't do that on a vintage machine if it were mine.  If I had a EuroPlus and wanted color I'd get a PAL card and then probably see if there is a PAL to HDMI adapter, or maybe I'd get one of the Apple II VGA cards.  I just built a few of those and man do they work good.  Super clear and crisp color display.

 

CVT
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It is very easy to convert an

It is very easy to convert an Apple II Europlus to NTSC:

 

1. Replace the crystal with a 14.31818 MHz crystal and connect a trimmer capacitor in series to it. The capacitance of the trimmer needs to be around 25 pF:

 

 

2. Separate the circular pads and connect the bow tie pads on the motherboard:

 

 

Result (my Apple II Europlus producing color NTSC video):

 

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Thank you CVT, appreciated!

Thank you CVT, appreciated!

 

This Europlus is going to be on display in a small no-profit local museum so we want it as it was intended but it's a nice thing to know for sure!

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I understand completely and

I understand completely and in this case I would suggest a green CRT monitor from the 80s, in case you can't get a hold of the original Apple II monochrome monitor.  Don't bother looking for a PAL card, because they were absolutely terrible in terms of picture quality. Only go with a color monitor if you can get a hold of a good RGB card.

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ahah good to hear about the

ahah good to hear about the PAL card!

 

Yes, we do have an Apple monitor II which I have also restored so the system is going to be up and running this weekend! :) 

I personally have an RGB capture device and I know the Apple II series can be tweaked to output such signal. I think one day I'd love to see a nice and crisp picture out of it!

 

As usual, I made a video of the repair. I made sure I quoted this forum and also explained that my "theories" were coming from this forum! :) Feedback is as always welcome!

 

https://youtu.be/l-cLiZzBxhw

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Oh, I'm also adding here my

Oh, I'm also adding here my final ROM bin file with all the ROMs concatenated together. This works with the Rom Replacement you can find here: https://www.blue-print.be/

 

Package iconRom_Replacement_AT27C256R_Complete_Correct_Order.zip

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Me again :) Not unexpectedly

Me again :)

 

Not unexpectedly for a 40-yo machine which has been in storage for decades, the Apple II Europlus has failed again. In a similar manner.

 

After a power cycle it would not auto-start. I moved the controller to slot 7 and it would auto-start again. I thought the same IC had failed again so I replaced it but that did not fix the problem.

 

This time:

- The floppy drive only works from slot 7

- If in any other slots, the computer hangs on APPLE ][. If I hit reset and type PR#6, the drive DOES NOT spin! If I remove the controller altogether, the computer drops me to Applesoft as expected.

- If I check the ROM with C700L etc, the controller is being seen in the slot it's plugged in but NOT in the others as expected. So when the controller is in slot 6, I see the controller ROM on slot 6 but NOT on slot 7.

 

So the slot selection seems to be working this time. But the computer cannot drive the floppy drive unless it's in slot 7. I'll try to educate myself and find the cause but if anybody has any ideas, please do let me know :)

 

Thanks!

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tony359 wrote:but if anybody
tony359 wrote:

but if anybody has any ideas, please do let me know :)

 

=> UB2, SN74LS154.

You verified that the slot ROMs work. That's the "IOSEL" decoder (UB4, LS138). The I/O registers of the slots are addressed through a separate address decoder (UB2). So this would be a usual suspect, which could cause the issue you describe.

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Thank you! I'm looking at

Thank you!

 

I'm looking at schematics but either I am misunderstanding them or I've got the wrong ones! :) 

Any chance you mean UH2, 74LS138PC? 

 

I'me reading the "understanding the Apple II" and I see the two selection logic. UH12 is the one I replaced which looks after the "I/O select", UH2 looks after the "Device Select" signals. Very interesting!

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Yes, sorry, I had the Euro

Yes, sorry, I had the Euro IIe schematics. On the II(Euro)+ it's UH2, 74LS138 driving the device select lines. Try replacing this one...

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Shall do, thanks for the

Shall do, thanks for the suggestion! :) 

 

If it's the UH2, it would be very weird to have two separate faults causing a similar issue on the same machine! :) 

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tony359 wrote:If it's the UH2
tony359 wrote:

If it's the UH2, it would be very weird to have two separate faults causing a similar issue on the same machine! :) 

 

Well, they were probably twins. Same type, probably made in the same factory and from the same lot. Worked together in the same machine, doing the same kind of work (address decoding, always running at full clock speed). If one of them decided it has had enough, the other is probably just as tired... :)

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I still need to look into the

I still need to look into the Apple II - might do that next week - but I'd like to understand what the difference is between the I/O select line and the Device select line? 

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Register vs ROM address range

Each slot has two address ranges. For slot s=1..7:

  • "DeviceSelect" is for the address range $C0s0-$C0sF. 16bytes, usually used for control registers.
  • "I/O Select" is for address range $Cs00-$CsFF. 256 bytes, usually used for a ROM (or RAM) area.

The Disk II Controller card uses both.

 

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Understood, thanks! Back to

Understood, thanks!

 

Back to the video signal of the Europlus, I still have a question. I thought the Europlus was an NTSC Apple II+ with 50Hz refresh rate? I could see the NTSC colour burst on my oscilloscope. I read it's a "BW" machine and I thought it's because a PAL monitor cannot interpret the NTSC colour burst. But none of my capture devices seem to be able to show colours on it and they should be  NTSC compatible.

 

Is that because of the refresh rate? Or simply because the signal is too "weird" for the capture device to display something? In other words, would I get colours if I used an appropriate colour CRT?

 

Thanks!

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tony359 wrote:Understood,
tony359 wrote:

Understood, thanks!

 

Back to the video signal of the Europlus, I still have a question. I thought the Europlus was an NTSC Apple II+ with 50Hz refresh rate? I could see the NTSC colour burst on my oscilloscope. I read it's a "BW" machine and I thought it's because a PAL monitor cannot interpret the NTSC colour burst. But none of my capture devices seem to be able to show colour...

 

The Europlus is switched to 50 Hz using the circle and bow tie pads (as I already mentioned above), but on top of that they also changed the crystal from 14.31818 MHz to 14.25045 MHz, which is not a whole number multiple of the NTSC color subcarrier frequency 3.579545 MHz or any other standard color subcarrier frequency. Because of that it doesn't fall into any of the composite color standards and no TV (or other device) will see it as a valid color signal.

 

I would switch it back to NTSC if I were you. By doing that you will be restoring it to a more original form, not less. One of the most amazing things about the Apple II is that it had color when it came out in 1977. This is what the people in the museum will be seeing on a good color CRT monitor:

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Thank you, now I understand

Thank you, now I understand!

There is a component of keeping things as original as possible there as you can imagine. If the Europlus was a BW machine, then I suspect it would be the museum's intention to show it as it would have been in the '80s. If a Colour machine is needed, we have plenty of Apple II+ and also Apple //e which could be restored and displayed to the public.

 

For now we have an original Apple Monitor II which is monochrome - the Apple colour monitor was designed for the /// and while it used to be sold as monitor for the Apple // series, it "doesn't look right" on top of an Apple II machine.

Anyways, it's good to know there are options. But if colours were needed, I think I would rather restore a proper Apple II+ instead - that should be a native NTSC machine, right?

(We do have TWO Apple /// monitors, one still has the mesh cloth on it, the other was removed. The one with the mesh looks amazing - even though I can imagine the picture quality was compromised by years of dirt!)

 

 

 

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tony359 wrote:...Anyways, it
tony359 wrote:

...

Anyways, it's good to know there are options. But if colours were needed, I think I would rather restore a proper Apple II+ instead - that should be a native NTSC machine, right?

...

 

If it comes from the US - yes. But if it was originally purchased from the UK (like mine Apple II+ was) it might not say Europlus anywhere, even though it is. The sure way to tell is to look at the circle and bow-tie pads on the motherboard or the frequency written on the crystal.

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ah, understood.  I feel that

ah, understood. 

 

I feel that if colour is needed, an Apple //e is the solution :)  

In any case, I would need to restore one of those two Monitor /// first before even thinking about colour!

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MacFly wrote:tony359 wrote:If
MacFly wrote:
tony359 wrote:

If it's the UH2, it would be very weird to have two separate faults causing a similar issue on the same machine! :) 

 

Well, they were probably twins. Same type, probably made in the same factory and from the same lot. Worked together in the same machine, doing the same kind of work (address decoding, always running a

 

It was indeed UH2, thanks for the help again!!

Now off to mod the ROM :)

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I made my usual repair video

I made my usual repair video - I'm showing both the fix and the ROM mod for the hard reset!

 

https://youtu.be/EkbGWgDkjF4

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I use a translator to read them

Thanks for sharing the video.

And thanks to all the other users for their explanations.

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During the actual years when

During the actual years when the Apple II Europlus was in production, I doubt any off-the-shelf monitor or TV was directly compatible with its "off-frequency" colour.  However, a custom modded TV might work, an approach that was actively investigated in the UK:-

"We also looked at Thorn TX10 as colour Monitor and TV for Schools. Experimented with the off frequency NTSC on European non-Colour Apple II by a switch changing crystal and disabling PAL switching... we never went into "production" of those though as the Apple II was falling out of favour and schools didn't want to spend the extra on colour for it."

 

The 240 volt Apple OEM colour composite monitors, sold in Australia and New Zealand ca. 1986 onward, are indeed backward compatible with the Apple II Europlus in colour.   There is a video showing this:-

https://youtu.be/o6CjY4InNNc

These monitors were particularly common in school environments - perhaps 30,000 or more had been sold by the early 1990's.

As per the video description:-  "Motherboard has factory standard Eurapple modification (Euromod) for 50Hz vertical timing and a 14.250 MHz master crystal (colour burst is 1/4 of this).  Regular PAL or NTSC displays generally interpret this "proprietary" signal in monochrome.  Colour is fully supported on 220/240V models of Apple's ColorMonitor IIe/IIc and AppleColor Composite Monitor IIe/IIc - as released in Australia & New Zealand and possibly elsewhere.  The more readily available 120V model AppleColor composite monitors only sync to NTSC 3.58 (American standard) and won't produce colour with Europlus."

 

 

 

 

 

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ben23239 wrote:During the
ben23239 wrote:

During the actual years when the Apple II Europlus was in production, I doubt any off-the-shelf monitor or TV was directly compatible with its "off-frequency" colour.  However, a custom modded TV might work, an approach that was actively investigated in the UK:-

"We also looked at Thorn TX10 as colour Monitor and TV for Schools. Experimented with the off frequency NTSC on European non-Colour Apple II by a switch changing crystal and disabling PAL switching... we never went into "production" of those though as the Apple II was falling out of favour and schools didn't want to spend the extra on colour for it."

 

I think he is talking about modding the Apple II, not the TV. The Thorn/Ferguson TX10 is a PAL TV that doesn't even have a video input, so modding it to show color from what the Apple II Europlus is putting out would be very complicated. It's very easy to mod the Apple II Europlus back to standard NTSC, and then use an NTSC->PAL RF converter on any PAL TV that only has an RF input.

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There were surely some

There were surely some individuals and schools achieving colour by undoing the euromods (voiding the Europlus warranty didn't deter them).   Can't speak for the modding potential of the Thorn TX10 but composite input was possible with an official AV kit:-

https://www.vintage-radio.net/forum/showpost.php?p=1350728&postcount=6

 

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Bonus find
tony359 wrote:

As usual, I made a video of the repair. I made sure I quoted this forum and also explained that my "theories" were coming from this forum! :) Feedback is as always welcome!

 

https://youtu.be/l-cLiZzBxhw

 

Ooo, the repair video caught an early clue about the problem in comment 48

Quick review: The disk controller was installed in slot 7, but its ROM was appearing at memory addresses for slot 7...and slot 6...and slot 5...and slot 4.

The ROM address for slot 3 seemed to be okay because it did not list the disk controller ROM there.  But look again!  There's KBD, the motherboard IO port for the keyboard, showing up in the ROM locations for slot 3!

 

Here's a screencap from 29-minutes into https://youtu.be/l-cLiZzBxhw?si=tcNxrU0KW57gGnMH&t=1767 in the repair video:

 

@tony359 eventually found and fixed the motherboard IO conflict with the slots, but it's fun to see that the video captured another clue that was overlooked at the time.

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