Mauro72 Posted February 25, 2017 Share Posted February 25, 2017 Hi, I have a coleco with out of sync i think with all games. Something like this: http://derbian.webs.com/c64diag/fault.htm?id=c19_1 I have 10,90v in pin 8 of RAMs (the 12v line). Its low? Any help? Thanks! Quote Link to comment Share on other sites More sharing options...
cdn2a Posted February 27, 2017 Share Posted February 27, 2017 So, first off.. it's a PAL Coleco. I don't know too much about those. You can test the VDP, but odds are your getting a signal. (Based on you screen shot.) Is the a tuneable slug/inductor in the modulator? For channel freq. The part you have circled is an old shcool inductor. Quote Link to comment Share on other sites More sharing options...
+nanochess Posted February 27, 2017 Share Posted February 27, 2017 In NTSC Colecovision, checking pin 36 of VDP chip right to center of a composite jack and GND in side should generate a stable black & white picture. I don't know about PAL, but it could be the same. If the picture isn't stable then the VDP chip is damaged and needs replacement. Quote Link to comment Share on other sites More sharing options...
Mauro72 Posted February 28, 2017 Author Share Posted February 28, 2017 Hi guys... It's a PAL version. nanochess, so i can connect a composite jack to pin36 (center) and the ground of VDP, external side of the jack (pin 1 may be, i need to search schematic of VDP). Ok, thanks! Quote Link to comment Share on other sites More sharing options...
Mauro72 Posted March 1, 2017 Author Share Posted March 1, 2017 Anyone know the specifications of that old inductor encircled? I want to change it. Thanks. Quote Link to comment Share on other sites More sharing options...
cdn2a Posted March 1, 2017 Share Posted March 1, 2017 They are ancient... They are rated by color codes. PAL is prob different from NTSC check here... If you desolder it you can measure it too. http://www.vishay.com/inductors/color-code-calculator/ Quote Link to comment Share on other sites More sharing options...
Mauro72 Posted November 22, 2017 Author Share Posted November 22, 2017 Hi again.. Trying with some cartridges, i noticed about sound. Is good, no problem. Here a small video with "Decathlon" game. https://youtu.be/JkmGIYVekJY Quote Link to comment Share on other sites More sharing options...
Jinks Posted November 23, 2017 Share Posted November 23, 2017 Mine does the same nfi how to fix Quote Link to comment Share on other sites More sharing options...
Mauro72 Posted December 6, 2017 Author Share Posted December 6, 2017 Mmmmmmm... suspect discovery. A pnp transistor, 2N3906 near vdp. Anyone can confirm the value of EBC in board? Thanks! Quote Link to comment Share on other sites More sharing options...
adamcon Posted December 6, 2017 Share Posted December 6, 2017 Mmmmmmm... suspect discovery. A pnp transistor, 2N3906 near vdp. Anyone can confirm the value of EBC in board? Thanks! Replace it anyway. This transistor is a huge problem in the ADAM data drives, and probably many other applications. Quote Link to comment Share on other sites More sharing options...
Mauro72 Posted December 21, 2017 Author Share Posted December 21, 2017 Fixed!!!! Mixed problems, faulty power supply and two bad vrams. Now working! Thanks! 1 Quote Link to comment Share on other sites More sharing options...
+nanochess Posted December 21, 2017 Share Posted December 21, 2017 Well done! Quote Link to comment Share on other sites More sharing options...
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