Retrocomputing

MACSIMM - Programmable ROM SIMM for Mac SE/30, IIfx and IIsi

Submitted by GG on Thu, 05/25/2017 - 18:46

The Mac SE/30 was the fastest of the classic compact black and white Macintosh computers. It featured a 16MHz 68030 with 68882 FPU and a 32-bit memory interface and supported, albeit not officially, up to 128MB of RAM. Unfortunately the SE/30 ROM contained some old code that used 24-bit addressing making it 32-bit dirty. Many classic computer enthusiasts make their SE/30 32-bit clean by installing a Mac IIsi ROM SIMM. These are nowadays quite rare and difficult to find.

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Retrocomputing

Apple

GRAM/512S - 512KB geoRAM clone for Commodore 64/128

Submitted by GG on Tue, 05/02/2017 - 02:25

The geoRAM is a 512KB memory expansion for the Commodore 64 and 128 designed by Berkeley Softworks for use with GEOS. While not as fast as the Commodore REU due to its lack of DMA capabilities, it still provides a significant performance boost. GRAM/512S is a geoRAM compatible cartridge based on a single 512Kx8 SRAM.

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Retrocomputing

C64

CGA2RGB-B01 - Digital RGBI to analog RGB for Commodore 128 and IBM PC CGA

Submitted by GG on Mon, 04/10/2017 - 09:59

A new version of this project is available here

The 80 column output of the Commodore 128 is the same digital RGBI used by the original IBM CGA graphics adapter. Unfortunately nowadays is quite difficult to find a monitor with the suitable RGBI input. The CGA2RGB adapter will convert the TTL RGBI to analog RGB suitable to be connected directly to a 15KHz capable RGB monitor or to the popular Gonbes GBS-8200 VGA converter.

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Retrocomputing

C64

GLINKUSB-LT-C01 - User Port RS232 to USB for Commodore 8-bit Computers

Submitted by GG on Tue, 03/21/2017 - 14:11

A new version of this project is available here

Filed under:

Retrocomputing

C64

F2R16-A00 - Flash based ROM Replacement for Amiga Computers

Submitted by GG on Tue, 02/21/2017 - 15:49

The Amiga, like many other computers of the late 80s, uses 16-bit wide mask ROMs to store the machine firmware. Unfortunately, the pinout of these ROMs is incompatible with the JEDEC defined EPROM pinout. Memory manufacturers produced "ROM compatible" EPROMS like the 27C400 to allow development and quick turn manufacturing. These EPROMS are however becoming quite hard to find and still require a UV lamp to erase the chips. F2R16 brings all the benefits of modern flash memory technology to any platform designed to use these obsolete devices.

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Retrocomputing

Amiga

GLINKUSB-LT-C00 - User Port RS232 to USB for Commodore 8-bit Computers

Submitted by GG on Sat, 02/04/2017 - 18:11

A new version of this project is available here

Filed under:

Retrocomputing

C64

CGA2RGB-B00 - Digital RGBI to analog RGB for Commodore 128 and IBM PC CGA

Submitted by GG on Wed, 02/01/2017 - 20:40

A new version of this project is available here

Filed under:

Retrocomputing

C64

CGA2RGB-A00 - Digital RGBI to analog RGB for Commodore 128 and IBM PC CGA

Submitted by GG on Tue, 11/15/2016 - 21:44

A new version of this project is available here

Filed under:

Retrocomputing

C64

GTERM25-A01 - DB25 Active SCSI Terminator with diagnostics LEDs

Submitted by GG on Thu, 11/10/2016 - 22:59

A new version of this project is available here

Active termination is required to get newer higher performance drives working on vintage computers. Unfortunately both the Amiga and older Apple computers use a DB25 SCSI connector which makes finding a suitable terminator quite difficult. GTERM25 solves this problem providing a high performance active terminator with a DB25 connector and SCSI diagnostic LEDs.