Any interest in a new Apple /// memory board?

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Any interest in a new Apple /// memory board?

I have PCBs and connectors arriving tomorrow for a prototype of a new Apple /// memory board, using modern components (e.g., CMOS SRAM). The initial version is a 256 KiB board, as proof of concept. Is this something anyone might want?

 

Compared to the Apple "5V" memory board, this uses much less power, so it doesn't need the power resistor from +12V to +5V that was present on the Apple board, and it puts less load on the power supply and generates less heat.

 

This new board will REQUIRE a "5V motherboard". In other words, the motherboard has to have the 5V PROMs, and R58 removed, and the mohterboard jumper installed. Any Apple /// that currently works with a 5V memory board is properly configured, as is any Apple ///+. Apple /// motherbards that currently work with a 12V memory board will not be compatible, unless the motherboard is upgraded to the 5V configuration.

 

And before everyone asks, yes, I know that everyone wants a 512 KiB board, like the On Three board. That's quite a bit more complicated. Although I've given it some thought, and my first board was designed with the intention of being capable of 512 KiB, I've already discovered that the current board design won't be able to do it.

 

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That's interesting.  I have a

That's interesting.  I have a working ///, but I don't really use it all that much.  I might get something like this just as a safety precaution, but of course the 512k card would be much more attractive.

 

 

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Does anyone do Apple ///

Does anyone do Apple /// these days?

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No, nobody uses them, because

No, nobody uses them, because they're obsolete. Just like the Apple II.

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I'd be interested in trying

I'd be interested in trying one. The memory board really seems to suffer, maybe a new low power version would help reliability.

Preference would be for a 512k version if possible.

 

/Rob

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photo of partially assembled prototype

I just finished soldering in the connectors, sockets, and passives. Here's a photo

The next steps will be

  1. test electrical connectivity (shorts or opens)
  2. test fit
  3. test that Apple /// powers up but does not run, same as with no memory board
  4. program CPLDs
  5. install chips
  6. go for broke
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brouhaha wrote:I just
brouhaha wrote:

I just finished soldering in the connectors, sockets, and passives. Here's a photo

The next steps will be

  1. test electrical connectivity (shorts or opens)
  2. test fit
  3. test that Apple /// powers up but does not run, same as with no memory board
  4. program CPLDs

 

Looks sweet!  If Apple had that RAM board when the /// first shipped it probably would have been a big success...

 

 

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Id be interested in a 512KB

Id be interested in a 512KB board for my III PLUS if you make one.

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I'm interested. I have

I'm interested. I have several Apple IIIs

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