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BBC Model B Issue 7 microcomputer with 8271 FDC

BBC Model B Issue 7 microcomputer with 8271 FDC
BBC Model B Issue 7 microcomputer with 8271 FDC
BBC Model B Issue 7 microcomputer with 8271 FDC
BBC Model B Issue 7 microcomputer with 8271 FDC
BBC Model B Issue 7 microcomputer with 8271 FDC
BBC Model B Issue 7 microcomputer with 8271 FDC
BBC Model B Issue 7 microcomputer with 8271 FDC
BBC Model B Issue 7 microcomputer with 8271 FDC
BBC Model B Issue 7 microcomputer with 8271 FDC
BBC Model B Issue 7 microcomputer with 8271 FDC
BBC Model B Issue 7 microcomputer with 8271 FDC
BBC Model B Issue 7 microcomputer with 8271 FDC

BBC Model B Issue 7 microcomputer with 8271 FDC

Four of my refurbished BBC Model Bs have found happy, new homes. This is the fifth I have completed.

I have a few more remaining - it takes time to ensure each one is working reliably again. This one includes an 8271 floppy disc controller and the original polystyrene packaging.

I have verified the disc interface works using a 5.25 floppy drive. I will also include one of my hand-made auxiliary power cables with splitter - you can run a 5.25 floppy drive and a Gotek floppy emulator from the Beeb's own power supply. I have repaired the power supply and have soak tested it for more than 12 hours continuous operation (Robotron in demo mode) with no issues. Both the RGB and composite video outputs have been verified.

The keyboard has been cleaned (keys individually washed in warm, soapy water) and the case has been scrubbed (cream cleanser in hot water). There is a small chip in the plastic on the right, front corner of the top case (see photos) and I have replaced the "ashtray" cover with a 3D printed replacement. I've made the following repairs/improvements. [1] Replaced a faulty 8255 VIA (IC3) with a new part.

[2] Replaced the "boring" red LEDs for the caps/lock shift with a green & blue LED. [3] Replaced the BNC connector for the composite video with a soldered-in RCA connector - no more having to unsolder the video connector if you want to remove the PCB! [4] Removed the TV modulator output and added an external on/off switch to select the composite video mono/colour output. [5] Upgraded the ROM sockets from 16KB to a 32KB and three 64KB - the 32KB socket accepts an SRAM for Sideways RAM (SWR).

[6] Installed a 62256 SRAM in IC101 for 32KB of SWR - tested. [7] Installed RetroClinic's CombiROM for 8271 (64KB 27C512) in IC100 - includes SWR utilities, DFS, BASIC. [8] Installed two games on a 32KB 27C256. In IC88 (Robotron & Arkanoid).

[9] Heat sinks have been attached to the hottest running chips. [10] Brand new screws for the power supply, keyboard and case. [11] The "ashtray" cover was a bit tattered (basically coming off) so I have replaced it with a 3D printed cover (see photos). Note that it doesn't include any software except for that included on the ROMs. You should be able to get a Gotek floppy emulator, flash it with the Flash Floppy firmware and then access BBC disc images from a USB drive. Happy to assist you with this. I will include a sheet of information on the modifications I've made. There is one ROM slot free - happy to include a 27256 (32KB) ROM containing two 16KB ROMs of your choice if you want. The item "BBC Model B Issue 7 microcomputer with 8271 FDC" is in sale since Wednesday, October 28, 2020.

This item is in the category "Computers/Tablets & Networking\Vintage Computing\Vintage Computers & Mainframes". The seller is "zepoonlufanio" and is located in Port Macquarie, NSW. This item can be shipped worldwide.

  • Model: Acorn BBC Micro B
  • Brand: Acorn

BBC Model B Issue 7 microcomputer with 8271 FDC