Apple //c • Screen anomalies on Startup with & with out disc.

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Hello everyone, and thank any of you in advance for shedding any light on my issue(s).

I bought an Apple //c. It came with the Green Display, 5.25" Apple //c external drive. The purchase also included some original discs as well as many "home brew" looking discs.

The challenge I face is this: When I boot up with or with out a Startup disc in the internal bay, I observed an artifact in the mid-lower/center of the screen.

Follow this link: https://youtu.be/bcyAhMvTb3s to view the video I made of the process. For what it's worth I rebooted again with out the disc in place. I got similar results.

Any suggestions on how to proceed this next?

Thank you again for you time and consideration. Oh this appears to be a ROM 1 unit. - Gary

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gsmcten's picture
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Re: Apple //c • Screen anomalies on Startup with & with out ...

Gary,

To rule out the Monitor, do you have a Flat Screen Display with RCA Input Jack that you can plug the computer into?

Start There although my first guess is Screen Refresh from the IIc.

Jeff M, what do you think?

Steven Smile

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Steven (gsmcten)

"Apple ][.....It's ALIVE!!!!!"

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Re: Apple //c • Screen anomalies on Startup with & with out ...

That looks a lot like bad memory. Have you done the system check? (open apple-close apple-control-reset).
You can also try to get a memory checker program like Mecc's, //c system utilities, etc.
Cheers

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Re: Apple //c • Screen anomalies on Startup with & with out ...

Jav,

Screen Refresh would be RAM, right?

At least I thought so.

I could be absolutely wrong. lol

Steven Smile

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Steven (gsmcten)

"Apple ][.....It's ALIVE!!!!!"

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Re: Apple //c • Screen anomalies on Startup with & with out ...

Hi,
I've just purchased an old Apple IIc.
I have a similar problem. At booth it shows three "zero" on the screen (see the attachment); any time and in the same position.
I've thought the problem was due to the RAM and I tried to lunch the ram test by means "open apple+ closed apple +reset" but no message on screen found and the test cycling continuosly.
I've tried also to connect via serial port but I'm not able to load ADTPro: sometimes the upload fails, some other it arrives to the end but after the ProDOS the connection fails.
I've also removed all the chip, clean the pins and restored...nothing.
I'm not able to understand if the problem is the RAM or the ROM or in case it was RAM, what ICS failed (there are 16 chips!!!).
Someone can help me?

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Posts: 305
Re: Apple //c • Screen anomalies on Startup with & with out ...

I already answered you in another forum...As for the chip there might be several not one. Do you have spare DRAMs and soldering skills?

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Re: Apple //c • Screen anomalies on Startup with & with out ...

Hi George!!
Also here! In the other forum I didn't have any news after my pic. Anyway, Soldering skills no problem. SDRAM spares...problem... I haven't it.
How is possible for you to find the chip to replace?

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Posts: 251
Re: Apple //c • Screen anomalies on Startup with & with out ...

Normally screen artifacts are symptom of bad ram. One of the poster's computer must be ROM 255 and when doing the self test it cycles. That's normal. You need a newer ROM to get more info and the "System OK".
Unfortunately it is almost impossible to know which chip is bad. You will have to start somewhere and begin replacing them with new ones. At least That's the only way I know.
The posters are lucky, sometimes the computer won't even boot.

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Re: Apple //c • Screen anomalies on Startup with & with out ...

Yes the ROM is 255.
The strange thing is that the characters on the screen is always the same and in the same place.
.
.

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Posts: 305
Re: Apple //c • Screen anomalies on Startup with & with out ...

From what I see the UF15 is dead. If I am right (I must be!) you owe me Wink But there might also be other defective DRAMs apart from UF15. I could send you some spare tested DRAMS with (NOT SDRAM!) for free but the sipping from EU to US is somewhat expensive compared to what is shipped in our case...

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Re: Apple //c • Screen anomalies on Startup with & with out ...

Hi Geogel, UF15 should be MRD4 RAM isn't it?
Why do you think it is this RAM? (...if a secret don't tell me Big smile )
Are you from US?

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Re: Apple //c • Screen anomalies on Startup with & with out ...

No, I am from EU (Bulgaria). Or as your assistant secretary of state Victoria Nuland said "Fuck the EU"... Hush...Insane(itor) is monitoring my posts and is about to prosecute me, so I should be more cautious and anonymous here, and hide my whereabouts, haha...But the shipping from EU to US takes roughly 2 weeks, sometimes less...I will use the cheapest shipping and everything will be free for you...

In the photo I see zeros instead of blank spaces...Zero has an ASCII code of 30h, while the space (blank screen) has ascii 20h. That means that the bit 4 in these 3 bytes is constantly set while it should be cleared upon power on by screen clearing rom routine. Of course, apple has the most significant bit set, but that is irrelevant. If you enter the monitor mode and try writing into that text page location (4xxh) you will see that you cannot write a zero into that/these bits/bytes.

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Re: Apple //c • Screen anomalies on Startup with & with out ...

ahahah why you say I'm from state of Victoria??? I'm from Italy, we are both EU citizen.
Now I'm going to try to make your test.
Anyway do you have a shop? How is possible to receive from you the correct chips?
Also, can you confirm me that the chip is MRD4?
Many thanks George! Wink

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Re: Apple //c • Screen anomalies on Startup with & with out ...

Buonasera! I thought you were from US. Victoria Nuland is a US assistant secretary of state and she is notorious for recently saying "Fuck the EU". Give me your address in PM and I will ship you tomorrow a couple of DRAMs...

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Re: Apple //c • Screen anomalies on Startup with & with out ...

Thx a lot, just done.
As soon as I'll receive I'll proceed to change the first you suggested.
Sorry if I insist George, but the UF15 is MRD4 indicated on the board serigraphy?
I owe you a beer!!! Big smile

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Re: Apple //c • Screen anomalies on Startup with & with out ...

Got the address. I confirm, according to the photos and docs, this is the chip. Do you have DIP16 socket(s)?

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Re: Apple //c • Screen anomalies on Startup with & with out ...

No I haven't but I can find near here without problem.

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Re: Apple //c • Screen anomalies on Startup with & with out ...

I will add sockets, too. If you don't like them just use yours...

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Re: Apple //c • Screen anomalies on Startup with & with out ...

Too nice!!
But is vintage computer a hobby for you or a part of your job?
You are very skilled as I can see...

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Re: Apple //c • Screen anomalies on Startup with & with out ...

The DRAMs are on their way to Italy Smile We'll see if Poste Italiane would be faster than usual...

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Re: Apple //c • Screen anomalies on Startup with & with out ...

I've removed and edited posts in this thread to keep it from ending up like the last one.

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Re: Apple //c • Screen anomalies on Startup with & with out ...

Back to Gary's question.

It could also be a RAM problem.
To be sure, you can use the RAM test in this thread.

I haven't tried this test on a //c but I believe it should work.
Just post the result here.

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Antony
Apple II forever

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Re: Apple //c • Screen anomalies on Startup with & with out ...

Hi Georgel,
well done, FIXED.
Unfortunately after 20 days your package hasn't arrived and I decided to order 4264-15 RAM from ebay.
I changed the UF15 as per your indication and....it works
https://drive.google.com/file/d/0B0toLyPSHMq3T3pXWHFZZ2lIZGs/view
Now the problem is the oblique rows on the screen.
They remain also with the PC off and the monitor ON, for this reason I can exclude the fauld of PC components.
The old IIc works perfectly, see below
https://drive.google.com/file/d/0B0toLyPSHMq3cTUyQloxT1hmWDA/view
I've already changed a capacitor in the screen supply circuit because it burned Smile
Can you help me on this task?

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Re: Apple //c • Screen anomalies on Startup with & with out ...

It will arrive I think. I have the receipt and you or I could file a complaint...Once I had a tracked box of item I had sold on ebay which arrived in Italy after...2 months! Poste Italiane is notorious for slow postage sometimes. Anyway my diagnosis is more important than the DRAMs themselves. Just lower the intensity of the monitor and you won't see the blanked beam lines.