File:IBM 5150 27256 EPROM on adapter in socket U33 (minuszerodegrees).jpg
Summary
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Photograph of an Intel D27256-20 EPROM fitted on a Retro Innovations "2364 adapter" (marked www.go4retro.com, with solder points A15, A14, A13 and GND) in BIOS ROM socket U33 of an IBM 5150 system board with MK4116 RAM (a 16KB-64KB board), the arrangement minuszerodegrees.net uses in place of the original 8 KB BIOS ROM. Cropped from a larger annotated image; the notes beside the photograph on the original say that the 5150 board sees only one of the four 8 KB blocks in the 27256, that the adapter as supplied selects the last 8 KB, and that the EPROM window should be covered once the result is satisfactory.
Source
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https://www.minuszerodegrees.net/5150/rom/IBM%205150%20-%2027256%20and%20adapter%20in%20ROM%20socket%20U33.png (retrieved 2026-10-25), cropped to the photograph.
Author
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minuszerodegrees.net.
Licence
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No licence is stated on minuszerodegrees.net. Reproduced with credit for repair reference.
File history
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 21:47, 25 October 2026 | | 865 × 845 (306 KB) | Josh (talk | contribs) | Full photograph (earlier crop was too narrow) |
| 21:46, 25 October 2026 |  | 372 × 845 (131 KB) | Josh (talk | contribs) | Upload for repair guide |
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File usage
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