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New CPU, I/O, & Motherboards for Lisa 1/2 and Lisa2/10

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Lisa2:
With the recent interest in reproducing Lisa PCBs, I feel that folks here may also be interested in the learning more about the Sapient Technologies boards.   I was involved in the development of these boards and can answer questions you may have about them.  The Sapient boards are designed to directly replace the original Apple boards and include some updates and enhancements.

To start with, here is a quick overview of CPU board:

Sapient Lisa CPU - A four layer direct replacement for the Apple CPU card with the these updates:
    a) All the apple revisions have been integrated in the  design ( no bodge wires or tacked on components ).
    b) A integrated ROM switcher.  ROM switcher supports up to 8 variants (depending on EPROM size), common choices are C, D, H, 3A. Additional ROM variants could support non-parity memory, 4MB support in H ROMs, and other minor tweaks.  Also supports both Lisa and Screen mod Vid PROMS.
    c) A jumper to enable a hardware inverse video mode ( that was in Apple's original design but never used )
    d) Some support for the RamBo 4Meg mod.
    e) Mounting holes added to better secure an XLerator to reduce chance of dislocation when being moved
    f) The bare boards are 100% electrically tested (so no open or shorted traces), and some units have been built, tested, and sold, so the boards are known to work and fit.
    g) "Hard gold" plating on edge connector for durability

We are planning to sell the unpopulated PCB's soon with the cost as low as possible to cover the PCB manufacturing.  If you want one, reply to this thread.

Thank you,

Rick

diogenes:
Hi Rick,

I have just purchased an unpopulated Sapient  Lisa CPU board from John Woodall- but my next question will be: where can I get these "special" Quarz oscillator, running not at 5MHz, but at an unusual frequency of 20.37504 MHz ? AFAIK only Lisa used this frequency- why is this necesary- can I run it with exactly 20.0000 MHz?
Next problems will be: where can I get these BOOT ROM's 4X EVEN and 4X ODD? And where can I get the Video ROM MASTER 4x ?

Thanks for any help!

Helmut

patrick:
Lisa has an internal monitor, so you don't have to take care of any video timing. Serial communication will be 2% too slow, but this should be acceptable.

All files for the Lisa ROMs are at bitsavers.org. You only have to buy the video state PROM from vintagemicros.

sigma7:

--- Quote from: diogenes on September 24, 2023, 09:15:28 am ---where can I get these "special" Quarz oscillator, running not at 5MHz, but at an unusual frequency of 20.37504 MHz ? AFAIK only Lisa used this frequency- why is this necesary- can I run it with exactly 20.0000 MHz?

--- End quote ---

Yes, as far as I know, you can use a 20 MHz oscillator. Decades ago I installed a 20 MHz crystal to repair a CPU board and AFAIK there were no issues.

I haven't figured out why Apple chose the unusual frequency... does anyone else know or have a probable explanation?

Now that there are "programmable" oscillators, some suppliers will program an oscillator to the frequency that you request, and 20.37504 MHz is no more difficult than 20.00000 MHz.

Looking at what DigiKey has today, choices for a 5V, TTL output, through hole programmable oscillator lead you to a selection of EPSON SGR-8002 parts. The board accepts both "full size" and "half size" oscillators.

Either the Standby or Enable control version will work as the control pin is grounded on that board. Either commercial or industrial temperature range is sufficient, and for this purpose 50PPM or 100PPM accuracy is irrelevant.

Picking one of the options, eg. https://www.digikey.com/en/products/detail/epson/SGR-8002DC-PTB/755251 it says it is a "value added item" which means that you should disregard the stock level of 0 as they make them to order. It says "Enter your frequency in Web Order Notes" so add something like "program SGR-8002DC to 20.37504 MHz". The programming is included in the price and is done within a day in my experience.

Note that the programmable oscillators require a special programmer (ie. not an EPROM programmer), and typically can be programmed only twice (they can't be erased and reprogrammed many times the way a UV EPROM can).

diogenes:
Hello and many Thanks for the infomation!

Back to the unusual frequency- could it be possible that it had something to do with the US TV Colour norm-even if the Lisa has no colour capabilities, the Lisa has a Cinch connector for external Monitors. The B&W composite signal should have no colour carrier, sometimes there is one, some surveillance  VTR's need that carrier for switching the automatic recording on and off - the NTSC colour carrier is at 3.58 MHz and sometimes at 4.43 MHz- could there be a sort of  a colour trap for avoiding cross color effects?
It's only a thought, because I'm working with old open reel and cassette VTR machines and TBC's
I just found another source for a suitable Quarz oscillator:

https://centuriontech.eu/product/customized_oscillator/

Is this a good company?

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