majormar Posted March 16, 2019 Share Posted March 16, 2019 I have a Coco 3 that is working great, except the video is a bit blurry especially around the letters on both the RF output and composite output. I have replaced all the electrolytic caps except for the one electrolytic that is on the RF module since that is really going to be a pain in the A$$. Any suggestions on other things I can try? I have attached some pictures for reference. Notice the letter "D" especially. I also notice some slight banding in the black border when using composite. Composite RF Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted March 16, 2019 Share Posted March 16, 2019 Don't suppose you have an RGB monitor to try with it? Also, NTSC or PAL? Quote Link to comment Share on other sites More sharing options...
AtariLeaf Posted March 16, 2019 Share Posted March 16, 2019 Try joining either the Tandy Color computer facebook page or the coco mailing list, either way is a great way to get feedback from the coco community. There are a few knowledgeable people here regarding the coco but you have a great chance at getting an answer within a much larger Coco group. Quote Link to comment Share on other sites More sharing options...
majormar Posted March 16, 2019 Author Share Posted March 16, 2019 Don't suppose you have an RGB monitor to try with it? Also, NTSC or PAL? NTSC and unfortunately no RGB monitor. Quote Link to comment Share on other sites More sharing options...
majormar Posted March 16, 2019 Author Share Posted March 16, 2019 Try joining either the Tandy Color computer facebook page or the coco mailing list, either way is a great way to get feedback from the coco community. There are a few knowledgeable people here regarding the coco but you have a great chance at getting an answer within a much larger Coco group. Thanks. I will check in on Facebook as well. Any other suggestions are welcome. Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted March 16, 2019 Share Posted March 16, 2019 Yeah, the only spitball suggestions I can offer are to see if tweaking the tuning capacitor TC1 will make any useful difference. It fine-tunes the color oscillator. Just take note of its original position in case it doesn't help. The other is to check that all the resistors around Q2 and Q3 are still in spec. There's also a capacitor connected to Q3 that looks kind of important. Q2 and Q3 themselves can also fall out of spec without completely dying due years of heat and stress. But without o-scoping the output, this is all guesswork. Quote Link to comment Share on other sites More sharing options...
majormar Posted March 16, 2019 Author Share Posted March 16, 2019 Yeah, the only spitball suggestions I can offer are to see if tweaking the tuning capacitor TC1 will make any useful difference. It fine-tunes the color oscillator. Just take note of its original position in case it doesn't help. The other is to check that all the resistors around Q2 and Q3 are still in spec. There's also a capacitor connected to Q3 that looks kind of important. Q2 and Q3 themselves can also fall out of spec without completely dying due years of heat and stress. But without o-scoping the output, this is all guesswork. Thanks for the hints. I did try the tuning cap and the other adjustments on the RF modulator, but it didn't really help. I will check out those other areas as well. I went ahead and bought a Switch-a-roo from https://cocomanbiz.wordpress.com/just to see the difference in RGB mode. It could just be that my memory of my childhood is sharper than reality Quote Link to comment Share on other sites More sharing options...
JamesD Posted March 16, 2019 Share Posted March 16, 2019 Composite has never been as clear as digital video output, but that's bad even for composite.Replacing the caps should have fixed it.Did you try a different cable?What type of monitor/TV are you using?If it's a TV, have you tried adjusting settings like sharpness?You are better off using the RGB output with an RGB to SCART cable, and a SCART to HDMI adapter. There are a couple people making these. Boysontech doesn't advertise them unless he has some made up for sale.https://cocomanbiz.wordpress.com/https://boysontech.com/ Try joining either the Tandy Color computer facebook page or the coco mailing list, either way is a great way to get feedback from the coco community. There are a few knowledgeable people here regarding the coco but you have a great chance at getting an answer within a much larger Coco group. Discord has become quite the hangout these days, and you can chat with other people via voice. 1 Quote Link to comment Share on other sites More sharing options...
potatohead Posted May 28, 2019 Share Posted May 28, 2019 This is a hack, but you can try a TV or PVM that will accept S-video. Connect the signal line, (inner wire), to both S-video chroma and Luma inputs. Dial back the color saturation and it may work well for you. Quote Link to comment Share on other sites More sharing options...
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