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Apple II Switch-A-Slot type card cage box

blakespot

blakespot

Experienced Member
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Apr 22, 2008
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Alexandria, VA (USA)
SCRG made a box in the '80s called Switch-A-Slot that let you effectively switch between 4 cards in 1 slot.

I have run out of slots (and/or power) and desire one of these devices, but they are not easily found.

It surprises me no one has started making a clone if this, with all the new II cards out there. Is anyone aware of such a thing, recently made? The original is nigh impossible to find.



bp


scrg_switch-a-slot.jpg
 
If all that thing does is turn the power off on the de-selected slots that could be... sketchy. You can get some weird behavior from TTL and CMOS logic where they'll "kinda work" by parasitically drawing power from the signal pins.
 
Eudimorphodon said:
If all that thing does is turn the power off on the de-selected slots that could be... sketchy. You can get some weird behavior from TTL and CMOS logic where they'll "kinda work" by parasitically drawing power from the signal pins.
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That's what it does but requires you turn off power to the ][. So it's more about the convenience of not physically opening and moving boards in/out. I think that's what you mean though... even then the data lines might draw power from the powered down boards?
 
booboo said:
I think that's what you mean though... even then the data lines might draw power from the powered down boards?
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More like the powered down boards might draw enough power from the still-connected data/address/signal lines for the logic on them to in turn generate stray output that could interfere with the "selected" card. Electrically it's "not great". In fact some component datasheets explicitly warn you against applying higher voltages to the signal pins than what's on VCC, which is essentially what you'll be doing to all the powered off cards; I suspect the actual potential for damage is *almost* nil, but almost nil is technically not zero.

A more kosher solution would probably be to keep the cards powered on, but buffer the control signals to ensure the deactivated cards will never look like they're selected. A non-trivial problem with that is some Apple II cards do pretty intrusive things to the bus. This would probably be easier with, say, ISA or other "Intel style" busses than it is with a 6502. (With a "simple" Apple card you could probably just buffer the card select line, Phi clock, and the /RW line. A card that does bus snooping/DMA or does stuff on the "non-CPU side" of the Phi cycle would be kind of a nightmare.)
 
oldpcguy said:
I'm curious to know what the OP has in all those slots.
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Its not hard to fill up the slots of an apple II if you have all the new fun gadgets they make today. Its harder to fill all the slots on a IIGS as everything is already built on the mainboard.
 
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