๐Ÿ‡ธ๐Ÿ‡ฐ Tesla PMD 85: Part 7 (Keyboard Issues?) [TCE #0447]

Channel:
Australia The Clueless Engineer
Subscribers:
1,990
Published on ● Video Link: https://www.youtube.com/watch?v=Hu5mys5Eccw


Duration: 22:25
281 views
22

Continuing on from yesterday's video [TCE #0446], I replaced the Tesla programmable peripheral interface (PPI) chip for the keyboard, MHB8225A, with a Western CMOS equivalent. It seems to have stopped the "key stuck on repeat" issue.

However I think I still have keyboard issues. Thanks again to Jakub@jjermar1 and Yura @yurasergienko6890 for their advice.

Jura pointed to a Hungarian video by@ATLAB where he details about replacing the rubber domes, and also identifies a replacement from Aliexpress:
https://youtu.be/SZ3X2oSUivU?si=S5t4uMJRMcQf75sG&t=1089

On Aliexpress they are described as ... "ฮฆ12*ฮฆ7*H6mm silicone conductive single keypads silicone buttons" ... so I'm thinking 12mm outer diameter, 7mm inner diameter and 6mm height ... ? This one page (that exists as of May 2024) they are "model DGQSDZ-KP58" ...
https://www.aliexpress.com/item/1005003193328919.html

https://archive.is/0Sk09#selection-2037.0-2037.11

I'm really wondering if designing a replacement keyboard might be a better solution ... ?

Time to have a look at the Robotron Kleincomputer KC 85 again I think ...



Other Videos By The Clueless Engineer


2024-05-29๐Ÿ‡ฏ๐Ÿ‡ต Panasonic RL-H1400 Handheld Computer: Part 2 [TCE #0459]
2024-05-27๐Ÿ‡ง๐Ÿ‡พ ะšะฒะฐะฝั‚ (Quantum): Part 2 (No video output) [TCE #0457]
2024-05-26ะะปัŒั„ะฐ ะ‘ะš (Alpha BK): Part 5 (Reset Button Added) [TCE #0456]
2024-05-25ะะปัŒั„ะฐ ะ‘ะš (Alpha BK): Part 4 (Making Progress) [TCE #0454]
2024-05-23ะะปัŒั„ะฐ ะ‘ะš (Alpha BK): Part 3 (Got Video Working!) [TCE #0453]
2024-05-22๐Ÿ‡ง๐Ÿ‡พ ะšะฒะฐะฝั‚ (Quantum): Part 1 [TCE #0452]
2024-05-19๐Ÿ‡บ๐Ÿ‡ธ Motorola Ultra Sleek Analogue Mobile Phone: Part 1 (Quick Look) [TCE #0451]
2024-05-18ะะปัŒั„ะฐ ะ‘ะš (Alpha BK): Part 2 (Troubleshooting Begins) [TCE #0450]
2024-05-14GoPro: Filtering Out Whistling From Driving Videos [TCE #0449]
2024-05-13๐Ÿ‡ฌ๐Ÿ‡ง Sinclair ZX Spectrum: Part 3 (Refurbishing continues) [TCE #0448]
2024-05-12๐Ÿ‡ธ๐Ÿ‡ฐ Tesla PMD 85: Part 7 (Keyboard Issues?) [TCE #0447]
2024-05-11๐Ÿ‡ธ๐Ÿ‡ฐ Tesla PMD 85: Part 6 (Video output!) [TCE #0446]
2024-05-09๐Ÿ‡บ๐Ÿ‡ธ Commodore VIC-20 for the Ham Shack: Part 1 (First Look) [TCE #0445]
2024-05-05Kleincomputer KC 85/3: Part 3 (Repairs & First Boot) [TCE #0444]
2024-05-04๐Ÿ‡ซ๐Ÿ‡ท Thomson MO5 "Platini": Part 1
2024-05-01Kleincomputer KC 85/3: Part 2 (Disassembly)
2024-04-28Kleincomputer KC 85/3: Part 1 (First look)
2024-04-25๐Ÿ‡ซ๐Ÿ‡ท Thomson TO8D: Part 1 (First look)
2024-04-24๐Ÿ‡ซ๐Ÿ‡ท Thomson TO7/70: Part 2 (Repairs made)
2024-04-20๐Ÿ‡ฌ๐Ÿ‡ง Sinclair ZX Spectrum: Part 2 (Refurbishing begins)
2024-04-17๐Ÿ‡ฌ๐Ÿ‡ง Sinclair ZX Spectrum & Interface 1: Part 1 (First look & test)