Vintage Computing Festival Berlin 2020

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en:sinclair-zx80-klon [2020/10/13 22:33]
xelalex [Building a Sinclair-ZX80 Clone] 		en:sinclair-zx80-klon [2020/10/18 22:09]
xelalex [Preparation]
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 {{:keyboard-adapter.jpg?direct&600|}} {{:keyboard-adapter.jpg?direct&600|}}
 +
 +**Update 18.10.:** The software for this adapter is now available on [[https://github.com/xelalexv/spectratur|GitHub]].
  
 ==== Status ==== ==== Status ====
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   * I found a first hint on //Tynemouth//'s troubleshooting page (the maker of the PCB). A white screen after power on is a known problem. It's usually caused by Vintage (sic! :-?) TTL chips in the graphics part of the circuit. These older chips are often not fast enough. In my case, this is probably a 74LS10, which I did not order new but used from my stock. I swapped it for a D110 (7410), just to check. This chip is also too slow, but I already see a change, so looks like I'm on the right track.   * I found a first hint on //Tynemouth//'s troubleshooting page (the maker of the PCB). A white screen after power on is a known problem. It's usually caused by Vintage (sic! :-?) TTL chips in the graphics part of the circuit. These older chips are often not fast enough. In my case, this is probably a 74LS10, which I did not order new but used from my stock. I swapped it for a D110 (7410), just to check. This chip is also too slow, but I already see a change, so looks like I'm on the right track.
 {{::progress-9.jpg?direct&400|}} {{::progress-9.jpg?direct&400|}}
-  * Today (13.10.) replacement for IC13 (74LS04) and IC17 (74LS32) arrived. After swapping, I get below picture. You can already imagine that there's something like a cursor, so definitely going in the right direction. Replacement for the remaining "Vintage" chips is on the way.+  * **Update 13.10.:** Replacements for IC13 (74LS04) and IC17 (74LS32) arrived. After swapping, I get below picture. You can already imagine that there's something like a cursor, so definitely going in the right direction. Replacement for the remaining "Vintage" chips is on the way.
   * {{::progress-10.png?direct&400|}}   * {{::progress-10.png?direct&400|}}
 +  * **Update 16.10.:** And now replacements for ICs 11, 12 (74LS00) & 16 (74LS10). After swapping them out, the picture improved again, but was still not correct. Then I noticed that when getting close to the ROM with my hand, the machine crashed. That triggered something, and I remembered that there are three jumpers that need to be placed according what type of ROM you're using (24 or 28 pins). According to the instructions, those jumpers should not be required when using a 28 pin ROM, but maybe that was meant for a different revision of the board. Due to the missing jumpers, three pins of the ROM were floating, and caused frequent crashes. 
 +  * {{::progress-12.jpg?direct&400|}} 
 +  * So,I quickly soldered them in place, and voilà... 
 +  * {{::progress-11.jpg?direct&600|}}
 ===== Virtual Exhibition Desk and Room ===== ===== Virtual Exhibition Desk and Room =====
  
en/sinclair-zx80-klon.txt · Last modified: 2020/12/31 12:52 by xelalex

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