Apple II Plus Keyboard needed-- Help!

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Apple II Plus Keyboard needed-- Help!

Hi,

I am looking for an Apple II PLUS keyboard. It does not have to be functional, or it is but has some broken keys. I need to repair my own keyboard which I recently broke one of the keys.

The Apple II plus keyboard is a built-in keyboard that has an attached keyboard encoder card underneath it. All I need at this point is the keyboard itself (sans the daughter card). Does anyone here have such item laying around?

-RocketScientists

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Apple II Keyboard

Hello there,

Recently i have been restoring an ol apple ii europlus.
It wouldn´t boot so i used a shot gun aproach and replaced most of the ttl chips and the 6502 cpu eventualy. Now it boots to apple ii logo!
The problem is that the keyboard does not work at all! only reset works...
The jumper cable connecting keyboard to the motherboard seems to be missing a pin in the motherboard side but it has no connection in the encoder board.
I have removed the rom chip from the encoder board and the reset key functions the same, so i presume the encoder board´s rom is bad...

Anyone can help? maybe there could be some way to test the rom or so...

Thanks in advance

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If your still looking rockets

If your still looking rocketscientists

Hint


I have a few keyboard parts left on the garage sale page of my website
http://www.willegal.net/appleii/forsale/appleii-forsale.htm

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Sounds like the daughter boar

Sounds like the daughter board on the keyboard is dead. (reset doesn't go through any ICs so it's the only one that should work regardless). What pin is missing?

Not sure how to test that other than if you had another known good Apple II/+ to try it on that [the daughter board]. If you want to test the ROM you'll need another similar daughter board to swap it into [which isn't a ROM if it's on the daughter board (your referring to the MM5740 (the keyboard encoder)). Your keyboard/character ROM should be fine if you can see APPLE ][ at the top]. If it's truly dead and you need a new one. I highly recommend Briel Computer's Apple II & II plus Super Encoder. I have one and it's awesome and very reliable as well.

P.S. hahah I took the shotgun approach as well and it paid off!

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Bad encoder

Hello,

I do not know the number, it is the pin pointing to the end of the motherboard on the right. Something like this: [.:::::::] the missing pin faces the end of the board and the missing one is the right one , nr16 i think. It doesn´t seem to be connected to anything on the board. I connected it back but the same result.
Thanks for pointing the encoder ic MM5740, with it´s schematic i will try and see if it is getting power and so on... Maybe i am lucky and some resistor is broken or so and can be fixable....
Is there a store selling the MM5740 ? The keyboard is in excelent condition so it is a shame to use an adaptor for external keyboard.

Another unrelated question, i can´t recall the boot process but it is normal for drive 1 to keep on forever if no bootable disk inserted? Mine does...only stops with reset and with no keyboard to test....

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side of case (right)

side of case (right)
---------------. [disregard the '-'s they keep the dot in place]
slots[.:::::::]keyboard
psu

if so that's pin 8 and is ground (it's important). It will cause the whole card not to work (including reset). If it's pin 9 or 16 your fine (NC). If it's pin 1 you have no power to any of the ICs on that board.
----------------------* [disregard the '-'s they keep the dot in place]
8 7 6 5 4 3 2 1
. . . . . . . .

. . . . . . . .
9 10 11 12 13 14 15 16

You've got to look around to find it. I found some at Sayal listed as MM5740AAD. http://sayal.com/ (I would give you a link but the site is designed by idiots). It plugs into your keyboard and you can use the Apple II's keyboard and/or a ps/2 keyboard. Your keyboard isn't the problem here. It's the encoder (daughter) card on the bottom. It also might not be the encoder IC that's gone (might be the other ICs on that card).

It's normal mine does the same thing. It will run forever if there is no disk. It will stop if it can't read a disk (ERR), or it has finished reading/loading the disk. If there is no drive attached to the card it should do the same thing, but if you take the card out it should start up and then give you the prompt without resting.

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Be forewarned. I've had issu

Be forewarned. I've had issues with the MM5740's from Sayal. Once warmed up, all three that I purchased don't operate properly . Well, I did get one to work by gluing a heat sink to it. An acquaintance had the same issue with MM5740's purchased from "Canada". Back in 2007 I did an extensive search for this part. I could find no other source for these parts, no matter what the quantity or cost. I've considered building a replacement board that would plug into the keyboard encoder's 40 pin socket, but that is way down the priority list.

Regards,
Mike Willegal

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Keyboard repair...

Seems Mike beat me to the reply. Also seems your shotgun approach fixed it? Anyway. yes you should have that pinf fix zs without vcc or ground the daughterboard is not powered up.

Mike's reference to the MM5740 part not working when things warm up. Apple II PLUS and Apple II have very tight timing between ICs. If you look carefully on the ICs (74ls logic, 4116 DRAMs. and the bus transceivers) you'll note there's an apple logo silkscreened on those parts. The reason? At that time Apple had to test invominh parts for timing specs (min/max timing in nanoseconds). Whenever parts died, you were recommended to buy the parts from Apple service with those Apple logo markings. That made sure they will function properly on the Apple motherboards. I remember blowing a bus transceiver once. I first called Apple suervice, they had one for $19 each. I wounded up buying a handful from Jameco Electronics (back in 1981). It took a couple of parts before it was stable. I relayed that finding back to Apple service. They explained the beforementioned process and that seems to be the same experience some folks have with those encoders.

Anyway, that's the engineering side of why those MM5700 failed.

Don't be too quick to junk your encoder chip. It may be the other compoents or the ribbon cable itself. You should use an ohm meter to check connectivity. Also that 25 pin HEADEER strip connection the daughterboard to the keyboard may have damaged or corroded. Check this by having the daughterboard attached to the keyboard. Using the ohm meter check connectivity by checking the two solder joints pairs one on the daughterboard and the other on the keyboard circuit board. Make sure you are checking the solder joints on the keyboard and not the pins the poke through when you mount the daughterboard. I found pin 14 on mine having no connection. It was the strobe for the "QWERTYUIOP" and would not recognize those keys. using a mod wire I just bypassed that problem.

I know it's wordy, but it illustrates the effort required to check and repair items.

MAKE SURE YOU ARe STATIC protected before doing any of this!! I posted a comment on someones post on this topic recemtly.

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Thanks for the info about the

Thanks for the info about the MM5740s from Sayal. I only recommend them because they are my local parts distributor. (I don't like them but they are the only one who I can deal with in person). Speaking of that does anyone know any parts distributors that sell to Canada and take PayPal, with a good site?

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Encoder chip checks

Thanks for all the help with this thirty year old keyboard!
Last evening i checked the voltages of the MM5740 chip and they wheren´t what i was expecting according to the mm5740 datasheets.
I was glad because it could be lack of power from the motherboard or ribon cable, so i connected a socket to the keyboard connector on the motherboard side and checked voltages according to the reference manual and all was ok, both 5 and -12v. I recurred to my apple ii bible for repairing this , the "Understanding the apple ii" by Jim Sather , and according to the encoder schematics ( page 342 ) it states the encoder ic is a ay-5-3600 , so i tested my ic according to the pin layout and this time the vcc and vgg pins had the correct values.

According to the schematics most of the data lines from the encoder ic goes through a 74ls04 ic, so according to the shotgun cientific methodology Smile i piggybacked another 74ls04 ic on top of the existing one (in the correct position ) but nothing...
I can buy a logic probe and test the "not´s" and "and´s" but i think the other components may interfere with the results.
I will download the 74xx ic´s datasheets and test the vcc/ground voltage... maybe they aren´t getting juice...

The keyboard pin connector missing is the 16 (keyboard [.:::::::] slots) according to apple manual so lucky me Smile .

I will test the 25 pin connections as sugested.

Thanks everyone

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New Apple iie board

Hi everyone,

First of all an update status of my attempts to ressurect a dead apple ii europlus:
In the end, i couldn´t fix the encoder board and gave up for now. I managed to connect a parallax basic stamp 2sx oem directly to the 16dip keyboard connector on the apple ii. The basic stamp is powered directly by the apple motherboard.The basic stamp oem board has a serial port, so i connected it to a pc and it works fine. On the pc side i run the hyperterminal and send keys directly to the basic stamp and it translates it to ascii . I have the basic source code for de basic stamp and i can take some pictures of the assembly, if anyone´s interested.
------------------------------------------------------------------

Anyway, i bought an apple iie motherboard recently from ebay and upon connecting it to the apple ii+ power supply it gave me squares on the screen. Later on i realised it was just self testing ram and bus in an infinite loop. I do not have a working keyboard to force the board to boot correctly.
Does anyone know of a way to make the board think it has a keyboard connected? Any ideas are welcome.

Regards to everyone,
Paul

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