omf Posted May 13, 2016 Share Posted May 13, 2016 Ok i have been trying to repair a american colecovision dead board so that i can use it with my f18a that has been giving me trouble on a pal board which there is a thread on here about it. I have found that the crystal that is on it is only attached by one pin which is a definite issue, it may not be the only issie the board has but its a good place to start. Can this crystal be replaced by a different value other than 7.15909 as getting one from Ebay from the us is a complete ripoff. 13.99 postage LOL If it does need to be this value if there a reasonable supplier in the uk? Acording to the coleco tech sheets it is the crystal at Y1 Any help or info would be appreciated Thanks Quote Link to comment Share on other sites More sharing options...
GroovyBee Posted May 13, 2016 Share Posted May 13, 2016 What is it for? Personally I would use a 28.63636MHz in a Pierce oscillator and then use some flip flops to divide by 4. That will get you a single ended clock source, at the right frequency for a quid or so. Quote Link to comment Share on other sites More sharing options...
omf Posted May 13, 2016 Author Share Posted May 13, 2016 What is it for? Personally I would use a 28.63636MHz in a Pierce oscillator and then use some flip flops to divide by 4. That will get you a single ended clock source, at the right frequency for a quid or so.It might be something to do with video but im not sure to be honest theres not much info on the tech docs i checked. I read somewhere it was video related I dont have access to any reference material right now due to writing this from a pub on the phone lol! It is on the page v-7 in the doc attached colecovision tech2.pdf Quote Link to comment Share on other sites More sharing options...
GroovyBee Posted May 13, 2016 Share Posted May 13, 2016 Looks like its something to do with U22 or U7. there only a capacitor part list in that doc. Quote Link to comment Share on other sites More sharing options...
SiLic0ne t0aD Posted May 14, 2016 Share Posted May 14, 2016 (edited) parkfun did a thread about crystals, messing with different values and how it affects speeds games run at, etc.. might not be a bad thread to search out Edited May 14, 2016 by SiLic0ne t0aD85 Quote Link to comment Share on other sites More sharing options...
omf Posted May 15, 2016 Author Share Posted May 15, 2016 Looks like its something to do with U22 or U7. there only a capacitor part list in that doc. The part list with the crystal is in document 3 I think i am going to merge all those pdfs into one, bit silly having 8 seperate ones in my opinion I wouldnt know how to set up that flip flop thing let alone what parts i would need to attempt it so probably best stick with whats there lol I have managed so solder some wires to the crystal stumps after if came off in my hand so i am going to attempt to re attach and see what hsppens probably still look for a new one though Quote Link to comment Share on other sites More sharing options...
GroovyBee Posted May 15, 2016 Share Posted May 15, 2016 I wouldnt know how to set up that flip flop thing let alone what parts i would need to attempt it so probably best stick with whats there lol No worries, it was just a thought. Its a cheap solution but you'd end up with a little piece of veroboard attached to the motherboard. Quote Link to comment Share on other sites More sharing options...
omf Posted May 15, 2016 Author Share Posted May 15, 2016 No worries, it was just a thought. Its a cheap solution but you'd end up with a little piece of veroboard attached to the motherboard. i dont mind that, as long as it works Quote Link to comment Share on other sites More sharing options...
GroovyBee Posted May 15, 2016 Share Posted May 15, 2016 i dont mind that, as long as it works I'll drop you a PM later. Quote Link to comment Share on other sites More sharing options...
omf Posted May 16, 2016 Author Share Posted May 16, 2016 i managed to bodge a temporary fix to see if it works or not (which it does) so this is indeed the offending item soldering wires to the stumps was not easy as there was basically no wires left and the wire area is very small so the is not a long term solution as the think gets in the way of the cartridge socket. so if left like this, i have no doubt that the wires will break off again soon. perhaps i could break into the metal casing to obtain a small amount of lead back to actually solder to? i am going to continue to socket all the chips and probably use new chips where i can for device longevity and easy repair later. m sure everyone would have paid £5 extra to have all sockets :/ Quote Link to comment Share on other sites More sharing options...
chart45 Posted May 16, 2016 Share Posted May 16, 2016 i managed to bodge a temporary fix to see if it works or not (which it does) so this is indeed the offending item soldering wires to the stumps was not easy as there was basically no wires left and the wire area is very small so the is not a long term solution as the think gets in the way of the cartridge socket. so if left like this, i have no doubt that the wires will break off again soon. perhaps i could break into the metal casing to obtain a small amount of lead back to actually solder to? i am going to continue to socket all the chips and probably use new chips where i can for device longevity and easy repair later. m sure everyone would have paid £5 extra to have all sockets :/ nice job on this board 1 Quote Link to comment Share on other sites More sharing options...
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