Request for info on kr3600/ay-5-3600 keyboard encoder IC

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I have an 820-0026-C keyboard encoder board attached to a pre-RFI Datanetics keyboard. Its being used with a rev 4 motherboard (II/II+).
The encoder board seems to match the schematic in Fig 7.8 of "Understanding the Apple II". The encoder IC seems to have an apple part # 331-0931-B, and manufacturer part # SMC KR3600-070 (instead of the AY-5-3600 in the schematic).

Unfortunately, it seems as though the keyboard encoder IC is faulty - some of the encoder IC's data output lines are floating at 1.65V instead of outputting the (inverted) key code.

I haven't desoldered the 74LS04 inverter to test independently, so for now, I'm assuming its the encoder itself that is at fault... I thought I'd check here first, before taking a soldering iron to the board...

There seem to be several KR3600-XXX flavors 'out there', but so far, I've failed to locate any datasheets that contain the key coding matrix of any of the variations. I was hoping I could find a more commonly available variation that might also successfully decode the apple key matrix.

Does anyone have such a datasheet - eg, that might allow me to identify other KR3600-XXX or KR9600-XXX variants that might decode the keyboard correctly, or already happen to know of variants that will work?

I'd also be interested in the same type of information for compatible AY-5-3600-XXX, or any other known compatible encoder ICs...

I'd appreciate any info you might be able to share - I'm a newbie at apple ii repair, but I would like to get this machine operational again, for old times sake.

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speedyG's picture
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Re: Request for info on kr3600/ay-5-3600 keyboard encoder IC

link to datasheet KR3600-XX:
http://www.datasheet4u.net/datasheet/K/R/3/KR3600-PRO_SMSC.pdf.html
there is also link to crossreference...
and for AY-5-3600 the link to datasheet is:
http://pdf1.alldatasheet.com/datasheet-pdf/view/151653/ETC1/AY53600.html
regards

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Re: Request for info on kr3600/ay-5-3600 keyboard encoder IC

thanks for the datasheet links, but I'm looking for more specific information about the variations of the key encoding configuration, rather than the data sheet for the general IC.

For example, I'd like to get hold of data sheet(s) containing the key mapping tables for a KR3600-004, or KR3600-017, or KR3600-070B1, KR3600-075B1, or KR3600-080, or and/ all of the other myriad that seem to appear in search results for kr3600.
I seem to have only found a whole heap of dead-end search matches, that either lead to reseller pages, or lead to abbreviated/ general datasheets that don't actually explain what the different mappings are for the different -XXX suffixes Sad

Maybe datasheets for these aren't available if they are all custom configurations, so as a fall-back, if any of you happen to know which specific ay-5-3600-xxx or kr3600-xxx (in case multiple variants were used by apple) is used on your ii/ii+ keyboard encoder board, that would help Smile

And for the AY-5-3600-xxx, since I don't have a board using one of these to eyeball, all I've managed to determine so far, is that the AY-5-3600-PRO is used in the //e and is not compatible with the ii/ii+ (from an applefritter post).

speedyG's picture
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Re: Request for info on kr3600/ay-5-3600 keyboard encoder IC

Have you taken a look in the linked Datasheets to the later pages of those documents ???
There is the mapping and there are tables to commen-standard-versions-mapping and the issued bits ( i.e. bytes ).....
the stuff is realy printed in awfull small graphic and awfull small letters in the tables but you can identify each single keypress in the tables and the generated bit-code..... the interpretation of the generated bitcode itself is handled by the computer and not by the chip ( i.e. at the AppleII its the mapping to the Char-Gen-ROM ! ) .

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Re: Request for info on kr3600/ay-5-3600 keyboard encoder IC

Another option is how original do you want to keep the machine.

Vince Briel from www.brielcomputers.com has a product called the "super encoder" it is a replacement board for the Apple II keyboard encoder. It also let's you plug a PS/2 keyboard in at the same time. Kinda neat... But it won't be original.

Regards,
Corey

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Re: Request for info on kr3600/ay-5-3600 keyboard encoder IC

@speedyG:
I couldn't find any actual datasheet via http://www.datasheet4u.net/datasheet/K/R/3/KR3600-PRO_SMSC.pdf.html
There are references to the -ST and -PRO chip versions, and tantalizing PDF icons, but no actual datasheets, no matter what links I followed on that site Smile I do have a datasheet for a KR9600-PRO and -STD which does happen to contain those two mappings, but they aren't the ones I'm looking for :/
Perhaps the link is now dead. However, if you happen to have the actual PDF containing mappings for other than the -PRO or -STD versions, please do let me know (eg a direct PDF link, or attach to post, or PM me please?)

I have an improved resolution version of the AY-5-3600 datasheet that you linked to, and compared the key mapping matrix against the key matrix in "Understanding Apple II" fig 7.8. The mapping doesn't line up as best I can see. For example, the datasheet figure 3 (page 5) shows "@" being decoded at positions X1,Y0 or X0,Y8 if SHIFT pressed, or X1,Y2 if SHIFT_CTRL pressed - but the appleii schematic has "@" on X1, Y9. Any of the keys I compared (maybe 10) didn't line up between the schematic and the data shee t table.

You mentioned that "the interpretation of the generated bitcode itself is handled by the computer and not by the chip ( i.e. at the AppleII its the mapping to the Char-Gen-ROM ! )"
Actually, I think you may be mistaken, at least in the case of the apple ii/ii+. You may be correct for the apple //e which uses a different keyboard encoder chip (I think it uses the -PRO, in combination with a ROM on the motherboard, but I haven't looked for the schematic to verify that).
If you look at "understanding apple ii" figure 7.2, you can see the data that is latched from the keyboard encoder chip outputs.

So, I'm still on the hunt for info, it seems :/

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Re: Request for info on kr3600/ay-5-3600 keyboard encoder IC

@Corey986:
Thanks - I have seen the Super Encoder, and I may eventually end up buying one. For now, I'm going to keep looking for an original or closely compatible repair part...

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Re: Request for info on kr3600/ay-5-3600 keyboard encoder IC

the 74LS04 hex inverter will be killed if someone plugs the keyboard in backwards on the motherboard, so check that first.

Regards,
Mike W.

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Re: Request for info on kr3600/ay-5-3600 keyboard encoder IC

@Mike WIllegal:
Thanks for the suggestion. I removed and tested the 74ls04 independently, and it is working. I repeated the encoder tests without the '04 in the circuit, and it was still producing invalid/ floating lines on its output pins. It eventually gave up the ghost completely, and no longer even strobes the keyboard lines. Sigh.

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Re: Request for info on kr3600/ay-5-3600 keyboard encoder IC

I too believe I have a faulty encoder (KR3600-070) in an Apple IIeuroplus I recently purchased.
I came across some encoder chips for sale on eBay (KR3600-080). It was only a few dollars so I thought maybe worth a try.

My question is can I expect to get some characters out of the machine even if they don't necessarily match the original encoder?

My plan B is the Briel encoder if this endevour is a failure !