+dhe Posted April 23, 2021 Share Posted April 23, 2021 I've heard the Geneve uses a crystal with an uncommon speed. I found this thread (above my head) - on what to do, if you need a crystal that's no longer made. https://www.eevblog.com/forum/projects/custom-frequency-crystals-where-do-you-order/ 2 Quote Link to comment Share on other sites More sharing options...
+Schmitzi Posted April 23, 2021 Share Posted April 23, 2021 wow cool if they would be programmable from inside MDOS, I can already see my next request: TURBO /24 ? 1 Quote Link to comment Share on other sites More sharing options...
+mizapf Posted April 23, 2021 Share Posted April 23, 2021 I hate to spoil the party ... 1 Quote Link to comment Share on other sites More sharing options...
+FarmerPotato Posted April 23, 2021 Share Posted April 23, 2021 11 hours ago, dhe said: I've heard the Geneve uses a crystal with an uncommon speed. I found this thread (above my head) - on what to do, if you need a crystal that's no longer made. https://www.eevblog.com/forum/projects/custom-frequency-crystals-where-do-you-order/ That’s pretty interesting. I didn’t know that there were custom crystal services. Still, the VDP crystal in the Geneva is just 6x the familiar video frequency, which is not hard to find. I ordered two brands from Mouser. It’s 21.477 MHz. Funny but I first got a 21.477 out of a HAM radio. 2 Quote Link to comment Share on other sites More sharing options...
+mizapf Posted April 23, 2021 Share Posted April 23, 2021 But is 12 MHz so uncommon? When I search for I get hundreds of hits. 1 Quote Link to comment Share on other sites More sharing options...
+FarmerPotato Posted April 24, 2021 Share Posted April 24, 2021 12 hours ago, mizapf said: But is 12 MHz so uncommon? When I search for I get hundreds of hits. dhe just heard there was an odd one. That has to be the 21.477 I asked Tayda if they could get them... they said no. Goldmine and Unicorn and other surplus places have not had them. Mouser and Digi-Key have such large catalogs that you can find a few. You could also build a frequency doubler around the 10.77 MHz which is much more common. Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted April 24, 2021 Share Posted April 24, 2021 While working at Cecure, there was some experimentation with operating the Geneve at higher frequencies. My recollection is that the top end was approximately 16Mhz. There was trouble with overall operation; were higher-speed 9995s manufactured and available back then? 1 Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted April 24, 2021 Share Posted April 24, 2021 I've actually got a 16 MHz 9995 that I purchased from the TI labs in Munich back around 1990. It is the only one I've ever seen in the wild, though. 1 Quote Link to comment Share on other sites More sharing options...
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