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Tranicos

Troubleshooting help: boots up and monitor just shows Apple ][ logo

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Howdy--I could use some assistance troubleshooting an Apple IIe that I recently got a hold of.

 

When I boot it up (with a disk in Drive 1), it only shows Apple ][ logo on the monitor (see pics). The drive light comes on and the drive is whirring, but doesn't sound like it's loading anything.

I've tried several different disks. I'm wondering whether it's most likely an issue with the computer itself, or the drive. I'm unfamiliar with the architecture of this sucker, so could use some compass headings to point me in the right direction. 

 

Any help appreciated!

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Not sure about apple iie. But on a apple ii. You can remove the card and see if it goes into apple soft basic. You can also hold down ctrl and press reset. See if it goes to basic. You are also welcome to swap the drive around. Perhaps you have a bad or dirty drive. Also not all disks are boot disks. Would help to know what disk you are trying to boot from.

 

Thanks,

 

Josh

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1 hour ago, ussexplorer said:

Not sure about apple iie. But on a apple ii. You can remove the card and see if it goes into apple soft basic. You can also hold down ctrl and press reset. See if it goes to basic. You are also welcome to swap the drive around. Perhaps you have a bad or dirty drive. Also not all disks are boot disks. Would help to know what disk you are trying to boot from.

 

Thanks,

 

Josh

Both are still true on the //e.

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Yes. and you have to be sure you have a good disk. AND be sure the head is spit-polished clean and operating with a firm (but properly tensioned) pressure-pad atop the disk surface. All it takes is one old disk to gum up the works. ONE DISK!

 

Failing that you can start cleaning the connectors in the drive and to and from the drive card itself.

 

I don't know how many early-style Disk II drives I fixed (that had a weak calibration banging sound) just by reseating the ribbon cable's internal connector.

 

Those are basic things you can do right away with a screwdriver and Qtip + alcohol.

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Thanks for the tips! I'll get started on cleaning, etc.

 

If I remove the disk controller card and boot, I get this prompt (see Pic with Apple ][ display). However, keyboard input doesn't seem to register via the cursor. 

 

If I press CONTROL-RESET then I get the cursor in the second picture. (see pic with no Apple ][ display) Again, no keyboard input appears.

 

As for disks: I have about a dozen games, so I've tried a few of those disks. I don't have any boot or system disks.

 

I have some equipment and have repaired a couple C64s, but I'm still new to this and haven't worked on an Apple yet.

 

--Tyler

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Edited by Tranicos

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Ok, progress! I cleaned both drives heads and connectors and was able to get one of them to work and a game to load.

 

Now just not getting keyboard strokes. However, the CONTROL-RESET and CONTROL-OPEN-CLOSED-RESET work.

 

The investigation continues...

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On 9/26/2019 at 11:40 PM, Keatah said:

What happens if you boot a disk that drops you to the "]" prompt? Can you type then?

 

Nope--unable to type. The only keys that work involve the Control, Reset, and Apple Keys (for that self-diagnostic)

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Do *any* keys type out OK?  Seems odd that reset works but no text.

How clean is the keyboard?  I could see some keys not working because of cold solder joints or dirty contacts.  But all keys except reset/ctl/apple?  Just seems odd.

 

Have you tested each key with caps lock and shift key engaged and not engaged?

 

I don't see any EEPROM chips in there so I assume the ROM is genuine Apple (meaning, no weird foreign ROM that messes with the keyboard).

 

I would inspect the solder joints on the keys, make sure the keys are clean, clean the contacts, etc.

 

Do you have a spare keyboard you can swap out to see if it works?

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I took the keys off and keyboard out and the solder joints look good (made one repair) and the keys are pretty clean.  I need to test the cable and I'll test every single key but my random hammering resulted in no keystrokes showing up.

 

I found another person online who posted about the same problem, but no solution yet.

 

I also found this resource and figured I'd try swapping the two keyboard-related ram chips if I can find out where to buy replacements:

http://apple2online.com/web_documents/apple_iie_repair_guide.pdf

 

Speaking of: any recommended vendors for chips?

Edited by Tranicos

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The keyboard decoder is separate from the reset circuit.  So that's how you can fail to get keypresses even though the various resets work.

 

Reset goes straight to the reset input on the 6502, but you have to also be holding CTRL to complete the circuit.  So that's all handled directly from the keyboard.

 

Open-apple and close-apple go to special select lines at the UC12 IC.

 

The keyboard itself is supposed to be decoded by UE14, an AY-5-3600-PRO keyboard encoder.  That outputs to UE12 which is an EEPROM that is probably for localization.  Caps-lock is an address input on that EEPROM, so that it can change what value it outputs based on whether caps-lock is up or down.  Shift and ctrl, on the other hand, are inputs to the keyboard encoder and affect its final output decision.

 

So either UE14 or UE12 are the likely causes for no keyboard input, when the keyboard itself seems to be okay.  UE4 (the MMU) is a distant possibility since it's supposed to activate the EEPROM whenever keyboard reads are desired.  UE5 (the IOU) receives reports of keys pressed, and obviously if it doesn't pass them on, the system will never be informed to read the keys.

 

On UE14, pins 1, 2, and 3 are used as the oscillator, so they should be oscillating.

Pins 5 and 16 are the "key ready" outputs and should strobe whenever a key is pressed.

Most of the pins between 17 and 40 are for reading the keyboard.  32-40 are the output strobes and you should always see them lighting up.  17-26 are the inputs and one should strobe when a key is pressed.  The keyboard grid is detailed here

Apple%20IIe%20Schematic%20-%20Keyboard.j

 

Edited by ChildOfCv
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FIXED! The culprit was the 3600 chip at E14. I found one on ebay and plugged it in and now the keyboard works!

 

The computer is in service--I'm excited! Just gotta troubleshoot why one of the drives doesn't work now, but at least it's not impairing anything atm.

 

Thanks for the advice!

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