Apple //e (white keys) motherboard revision

[KP]

Is there a way (other than, for example, trying to play a DHR game like Bad Dudes on it) to detect whether my white-keys //e is a Rev. A or Rev. B? It is enhanced, for what that is or is not worth.

[D Finnigan]

Post by KP
Is there a way (other than, for example, trying to play a DHR game like
Bad
Dudes on it) to detect whether my white-keys //e is a Rev. A or Rev. B?
It
is enhanced, for what that is or is not worth.

The revision letter is marked on the motherboard. Read the part number
printed to the left of the green copyright notice. Starts with 820...

[Brian Patrie]

Post by KP
Is there a way (other than, for example, trying to play a DHR game
like Bad Dudes on it) to detect whether my white-keys //e is a Rev. A
or Rev. B? It is enhanced, for what that is or is not worth.

I think it's possible to upgrade a Rev A IIe to enhanced, so
enhancedness not a foolproof indicator that it's DGR,DHGR capable.

To test it: from freshly powered on, enter:

PR#3
HGR
POKE 49246,0

If it's DHGR capable, you should end up with memory garbage from auxmem
interleaved with black vertical bars from mainmem.

[Mitchell Spector]

Post by KP
Is there a way (other than, for example, trying to play a DHR game like Bad Dudes on it) to detect whether my white-keys //e is a Rev. A or Rev. B? It is enhanced, for what that is or is not worth.

The most fool proof method is to look at the motherboard itself.
Examine the part number at the top-center, above the card slots.

You will see 820-0064-A for the revision 'A', and 820-0064-B
for the revision 'B'. Note there was a third revision that used the
'A' label again, and that was 820-0087-A, but is functionally a 'B'
revision board. iI is notable for having a 1984 copyright date
and the Enhanced chip part numbers silked screen on the board.

Of course the motherboard used in the Platinum Apple IIe is
also functionally a revision B board. I don't know the part number
off the top of my head, but it is visibly different as there are far
fewer chips present (firmware combined into "CD" ROM, and
just a pair of 64Kx4 DRAMs. Also likely a 1986 copyright date).

I believe Apple recommended against installing the Enhanced
chipset in rev 'A' boards, but it would still work. You just would not
have the capability to use Double-Lo/Hi-Res graphics or have
the special video data signal accessible through slot-7.

Mitchell Spector