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These are all SWP (South-Western Products, not to be confused with SWTPC) RAMDISK / 8088 MS-DOS adapter boards. Designed for various CP/M machines of the day, these commonly found their way into Kaypro machines, with Zorba machines being a distant second of sorts.

These are designed to sit on top of the drive stack, plug into the CPU port (the Z80 was pulled and placed on an adapter board) and some special software twiddling gave you a 256k - 1MB RAMDISK (depending on the model) or a MS-DOS mostly-compatible machine that used the host as a terminal.

These were purchased in 2013 and had some of the "missing link" software with them which has now been entered into various archives. The boards themselves are of unknown status, but are being kept around as spares for my working unit. The boards themselves date to the 1984/5 time period.

These are all SWP (South-Western Products, not to be confused with SWTPC) RAMDISK / 8088 MS-DOS adapter boards. Designed for various CP/M machines of the day, these commonly found their way into Kaypro machines, with Zorba machines being a distant second of sorts. These are designed to sit on top of the drive stack, plug into the CPU port (the Z80 was pulled and placed on an adapter board) and some special software twiddling gave you a 256k - 1MB RAMDISK (depending on the model) or a MS-DOS mostly-compatible machine that used the host as a terminal. These were purchased in 2013 and had some of the "missing link" software with them which has now been entered into various archives. The boards themselves are of unknown status, but are being kept around as spares for my working unit. The boards themselves date to the 1984/5 time period.

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[–] • 1 pt

The clock chip should be an 8284A.

The blue "chip" is a Bourns 16-2-103 10K isolated resistor pack, the one says "8140" or 40th week, 1981.

[–] [deleted] • 1 pt

Man, I've seen a million SIP resistors but never a DIP... sweeeeet.

[–] • 1 pt

They were common on 70s and 80s stuff, with 90s stuff being SOIC versions. You've probably seen them on newer boards, just didn't recognize it because they look like any other device now.

Bourns and Dale used harvest gold cases Bourns used blue cases Beckman used white ceramic and black plastic GenericCo used any color, I've seen red, blue, black, white, etc.

Not an exhaustive guide, but you can usually assume the manufacturer from the color. Not always, but usually.

[–] [deleted] • 1 pt

Dale used harvest gold cases

These ones I used in a level translator circuit x20 with BS170's to interface 28v discrete signals down to 3.3v to interface with my FPGA traffic cop. Probably saved me hours of soldering single resistors. That x20 circuits were a pain in the ass...

Wouldn't do that now, it's so easy to get a one-off PCB these days it doesn't make sense to build prototypes like in the days before.