| Microsoft 16K card [message #398866] |
Sun, 30 August 2020 12:14  |
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Originally posted by: can...@gmail.com
Hoping that there are some out there that are familiar with how the Microsoft 16K RAM expansion card works.
I'm having an issue where the computer is not recognizing the card. It does not see the the card is present (Locksmith 6 has a RAM card utility that scans all slots as does Apple Cillin.
The computer seems to start up normally with the card in place, and all the RAM chips check out fine (I transplanted them to the lower 16K on the motherboard and they work).
Rather than brute force repair chip swapping one by one I was hoping that someone would know what the issue might be so that I could target the right spot on the card.
Sadly Jim Sather's book Understanding the Apple II doesn't schematic or explain the Microsoft 16K card, only the Apple Language card which while similar is different enough (contains an f8 ROM aboard) that several concepts don't apply.
Any help would be appreciated.
Thanks
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| Re: Microsoft 16K card [message #398878 is a reply to message #398866] |
Sun, 30 August 2020 14:23  |
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Originally posted by: Greg Wildman
On Sun, 2020-08-30 at 09:14 -0700, can...@gmail.com wrote:
> Hoping that there are some out there that are familiar with how the
> Microsoft 16K RAM expansion card works.
>
> I'm having an issue where the computer is not recognizing the
> card. It does not see the the card is present (Locksmith 6 has a RAM
> card utility that scans all slots as does Apple Cillin.
>
> The computer seems to start up normally with the card in place, and
> all the RAM chips check out fine (I transplanted them to the lower
> 16K on the motherboard and they work).
> Rather than brute force repair chip swapping one by one I was hoping
> that someone would know what the issue might be so that I could
> target the right spot on the card.
>
> Sadly Jim Sather's book Understanding the Apple II doesn't schematic
> or explain the Microsoft 16K card, only the Apple Language card which
> while similar is different enough (contains an f8 ROM aboard) that
> several concepts don't apply.
>
> Any help would be appreciated.
Putting on my magicians hat,
Is this your card ?
https://mirrors.apple2.org.za/Apple%20II%20Documentation%20P roject/Interface%20Cards/Memory/Microsoft%20RAMCard/Manuals/
--
Greg
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| Re: Microsoft 16K card [message #399205 is a reply to message #398975] |
Thu, 03 September 2020 16:17 |
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Originally posted by: can...@gmail.com
On Tuesday, September 1, 2020 at 8:09:04 AM UTC-3, can...@gmail.com wrote:
>>> Putting on my magicians hat,
>>> Is this your card ?
>>>
>>> https://mirrors.apple2.org.za/Apple%20II%20Documentation%20P roject/Interface%20Cards/Memory/Microsoft%20RAMCard/Manuals/
>>>
>>> --
>>> Greg
> Interesting discrepancy in the card schematic to the actual card. Slot pin 18 (R/W) is also connected to pin 3 of the 4116 chips (MR/W) effectively bypassing the logic gate at U17.
>
> The card died when -12V was inadvertently applied to slot pin 18 (directly adjacent to slot pin 33 (which is -12V).
> (It also killed 4 chips at various places not he motherboard but those were found and replaced)
Everything just got all weird.
I have a known good Microsoft 16K card that would not work in this machine along with the suspect card. Computer does not recognize that there is a 16K card in slot 0.
Took a known good clone 16K card and put it in. No issues seeing it. Works perfectly. Passes all tests. Boots ProDOS no problem.
Put the suspect card into another II+. The card works perfectly. so does the known good Microsoft 16K card.
So the situation is now that I have a II+ that doesn't recognize Microsoft 16K cards, but will recognize other 16K cards of a slightly different design.
What would case it to stop recognizing them? It has to be motherboard related...
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| Re: Microsoft 16K card [message #399230 is a reply to message #399205] |
Thu, 03 September 2020 21:20 |
Michael J. Mahon
Messages: 1770
Registered: October 2012
Karma: 0
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Senior Member |
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can...@gmail.com <can7700@gmail.com> wrote:
> On Tuesday, September 1, 2020 at 8:09:04 AM UTC-3, can...@gmail.com wrote:
>>>> Putting on my magicians hat,
>>>> Is this your card ?
>>>>
>>>> https://mirrors.apple2.org.za/Apple%20II%20Documentation%20P roject/Interface%20Cards/Memory/Microsoft%20RAMCard/Manuals/
>>>>
>>>>
>>>> --
>>>> Greg
>> Interesting discrepancy in the card schematic to the actual card. Slot
>> pin 18 (R/W) is also connected to pin 3 of the 4116 chips (MR/W)
>> effectively bypassing the logic gate at U17.
>>
>> The card died when -12V was inadvertently applied to slot pin 18
>> (directly adjacent to slot pin 33 (which is -12V).
>> (It also killed 4 chips at various places not he motherboard but those
>> were found and replaced)
>
> Everything just got all weird.
> I have a known good Microsoft 16K card that would not work in this
> machine along with the suspect card. Computer does not recognize that
> there is a 16K card in slot 0.
> Took a known good clone 16K card and put it in. No issues seeing it.
> Works perfectly. Passes all tests. Boots ProDOS no problem.
>
> Put the suspect card into another II+. The card works perfectly. so
> does the known good Microsoft 16K card.
>
> So the situation is now that I have a II+ that doesn't recognize
> Microsoft 16K cards, but will recognize other 16K cards of a slightly different design.
>
> What would case it to stop recognizing them? It has to be motherboard related...
>
>
You might want to check the -12v line—from what you’ve said, it’s taken
some stress. ;-)
--
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com
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