Apple II+ display and disk issues

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Apple II+ display and disk issues

Hello: 

I am new to this site and this is my first post.  I recently purchased an early Apple II+  from the estate of its original owner (motherboard date code is 7934).  I am trying to sort out a number of issues to get it back up and running.

1) The computer did not boot at first (horizontal lines, no text).  After removing all cards and all but the first bank of RAM and removing, cleaning and reseating most of the chips on the motherboard, it now boots up into Applesoft but I see moving vertical bars and text has fringes of orange/blue or green/purple (see photos).   I have tried running the video output to an LCD TV and through a composite-HDMI converter  to an LCD monitor and I get the same results.  Is this normal or is there some adjustment that can be made?  Is it possibly a sign of a failing power supply?

 

2) I have been able to put back all of the memory and reinstalled the 16K language card and the disk II controller and drive.   The computer came with a DOS 3.2 master and a bunch of unlabeled diskettes.  The drive does not seem to read anything.  I tried loading an image from Apple II Disk Server but the drive makes a BLAT sound (that I remember was a bad sign) and I get a disk error.   The inside of the Disk II appears to be clean.  The head mechanism moves freely and there is no gunk on the head.   Is this indicative of a problem with the drive/controller or expired media?   The diskettes I have are not labeled so I am not sure if they are DSDD or DSHD.  Can the Apple II read/write DSHD disks?    

 

3) On a few occasions, the display has suddenly disappeared and the only way to get the computer back up is to unplug and re-plug the power supply from the motherboard .  Is this a sign of power supply issues or something else?

 

Thanks for your help and happy holidays!

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Color fringing on an early ][

Color fringing on an early ][+ is fairly normal.  Some newer LCD will not give a good picture from an Apple ][+'s non-standard NTSC signal.  You need to test your Disk ][ with a known good floppy.  If you have an early Disk ][ Controller card it may have 13 sector PROMs on it.  DOS 3.2 is 13 sector so that is a possibility.  13 sector PROMs will not boot a 16 sector disk, and most are 16 sector.  DSHD floppies do not work well on an SSSD system like an Apple ][.  DSDD (Double density) is OK, but not High Density.

 

You should meter your power supply, it should be close to spec levels when loaded.  Unloaded readings don't mean much as some power supplies will show close to correct unloaded but will be out of spec under load.  A failing supply will sometimes produce poor video, but usually you will get nothing or highly unstable operation.  Again, meter it.

 

 

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That is normal for Apple II

That is normal for Apple II to look like that on an LCD- you won't be able to fix it. It is designed to take advantage of 1970's TV technology, so find yourself an old CRT with composite input, or an old monochrome monitor.

 

As for the booting, it could be a 13-sector card, but that would be odd. Much more common and likely is the cable was plugged in backwards sometime over the last 40 years and it killed the analog card in the drive and /or the Disk ][ card in the computer.  I assume you've tried to boot all the disks, and if none of them boot or do anything, likely that is the problem.

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If the analog card is blown,

If the analog card is blown, most of the time it is the 74LS125 chip.  That often acts as a "fuse" for the system.  Luckily, that part is readily available and cheap, and since they are normally socketed, easy to replace.

 

To determine if the controller is 13 sector, one would have to look at the part numbers for the PROMs.  Here is the best article I found on how to do that.

 

https://stason.org/TULARC/pc/apple2/faq/09-017-How-does-one-distinguish-between-a-13-and-16-sector-D.html

 

 

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As for LCDs on Apple II, it

As for LCDs on Apple II, it is hit or miss.  Some rittwage is absolutely correct -- pretty much nothing you can do will ever get a good picture.  Others will work just fine.  I have a cheap Emerson branded 19" 720p TV with composite inputs and it works surprisingly well with a ][+ or //e.  Graphics look good with reasonable color fidelity and even 80 column text is readable.  It actually works as well or better than many period CRT monitors.  But I've seen some TVs that were as bad or worse than the picture posted in the original message.  Unfortunately, it is kind of trial and error to find one that will work well enough because sometimes even the same model number TV or monitor can have a different motherboard version or firmware revision and it can make a big difference.

 

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Here is some technical info

Here is some technical info on working on the Disk ][ system.

 

https://apple2online.com/web_documents/apple_disk_ii_technical_procedures.pdf

http://www.appleii-box.de/H084_5_AppleIIDiskService5.htm

http://apple2.org.za/gswv/a2zine/faqs/Csa2FDRIVE.html

http://www.willegal.net/appleii/apple-service-notes.pdf

 

Oh and FWIW, most often I've found the MC3470 to be the 2nd most common chip to blow on a Disk ][ Analog Card.  So if replacing the 74LS125 doesn't fix it, that would probably be the next one I'd try.

 

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Hello softwarejanitor,just

Hello softwarejanitor,
just one simple request:
If you refer to othe sites, please make sure that reference is correct.
In my case at my site the reference to:
http://www.appleii-box.de/H084_5_AppleIIDiskService5.htm
insn`t correct....
The reference to the correct entrypage is:
http://www.appleii-box.de/H084_1_AppleIIDiskService1.htm

sincerely
SpeedyG

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What do you mean by "correct"

What do you mean by "correct"?  The link I provided displays the page that I intended.

 

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Thanks for all the input. 

Thanks for all the input.  I have confirmed  by part number that I have the 16-sector PROMS.

I have tried pulling, cleaning and reseating the ICs on the disk controller card and on the analog board and nothing has changed.

The local electronics shop is closed today so I will go get my hands on a new 74LS125 tomorrow and hopefully that will fix things.   The MC3470 seems to be a bit harder to come by so I hope that it is still good...

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Another bad part of that

Another bad part of that fault with the disk drive board... If this is indeed the problem and you tried to boot every disk, then track 0 will now be erased on all of them. :(

 

 

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This doesn't always happen. 

This doesn't always happen.  Also, if I remember right it is the Duodisk or Unidisk 5.25 that are more prone to this issue than the Disk ][.

 

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I doubt it, since you can't

I doubt it, since you can't even plug those disk drive cables in wrong. Well, unless you really, really tried.

But yes, I've had seen the reversed or mis-keyed cable erase every disk put in the drive on Disk II's many times.

 

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There are other ways to blow

There are other ways to blow the 74LS125 that can happen to the Unidisk 5.25 and Duodisk.  You can't plug the cable in backwards or off a pin very easily but you can plug or unplug it at the wrong time.  I've just heard of numerous cases of Unidisk or Duodisk drives that would erase disks.  I've never had it happen with a Disk ][ myself, knock on veneer.

 

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I have replaced the 74LS125

I have replaced the 74LS125 but that has not changed anything :(   Does anybody know where I can get an MC3740 or better still a tested working Disk II at a reasonable cost?     

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Depends on what you consider

Depends on what you consider a "reasonable price".  I've been able to pick up a few Disk ][ off eBay over the past few years in the $20-$25 range.  There are always a bunch for sale.  Tested, not usually because 90+% of the people selling them are completely clueless, but most of the ones I've bought that weren't cheaper than that and known to have some issue have been fine.  I've picked up a few parts drives for around $10 each.  The shipping was more than the drives themselves by a couple bucks.  But buying through eBay or something like that is about the only place you're usually going to reliably find them.  There used to be a few sites that sold tested and working drives a few years ago, but they generally were 2-3x more, for their trouble of testing and maintaing inventory, which is only fair.  But at those kind of prices you can buy a couple of them and more than likely end up with at least one working drive and some spare parts.

 

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Over the last few weeks, I

Over the last few weeks, I have been looking on eBay and at some resellers and it seems like working/tested or non-working drives are going at the $50+ range .  I am in Canada so I need to add shipping and duties plus roughly 30% currency exchange rate.  It is the shipping and currency conversion that really hurt. 

Ideally, I'd like to find a tested, working drive from a seller in Canada or the northeast US to minimize shipping costs.

For some good news, I did manage to get my hands on a Commodore 1702 monitor and the display issues have gone away. 

  

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Like anything on eBay, you

Like anything on eBay, you have to be dilligent and patient to find the good deals.  I would never pay $50 for a Disk ][ drive, there are just way too many of them out there.  Shipping does suck.  I just plain won't deal with international shipping except for stuff coming from China, which is cheap enough to put up with how slow it is.

 

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Here is two for $50 BIN OBO
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No response from North Dakota

No response from North Dakota.  However, I did receive my FloppyEmu in the mail today.  I have been able to run diagnostics on the computer and everything seems to check out.  I was even able to run CP/M with the Microsoft Z80 card that came with the machine and that is working fine.   I can play around with the machine for now but I still want to get the floppy drive running at some point.  I have ordered some of the other chips on the analog board that tend to blow and we will see if that helps.

 

For now I still have a couple of keys on the keyboard that are not working and I would like to get my hands on an 80 column card -- how much do those go for these days? 

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e30_325is wrote:No response

e30_325is wrote:

No response from North Dakota.  However, I did receive my FloppyEmu in the mail today.  I have been able to run diagnostics on the computer and everything seems to check out.  I was even able to run CP/M with the Microsoft Z80 card that came with the machine and that is working fine.   I can play around with the machine for now but I still want to get the floppy drive running at some point.  I have ordered some of the other chips on the analog board that tend to blow and we will see if that helps.

 

For now I still have a couple of keys on the keyboard that are not working and I would like to get my hands on an 80 column card -- how much do those go for these days? 

 

I've seen Videx Videoterm clones go for $30-$50 on eBay fairly frequently.  The nice thing about a lot of the clones is that many of them have the "soft switch" functionality built in which is nicer than the original Videx cards.

 

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