copperboy Posted September 9, 2021 Share Posted September 9, 2021 Does anybody here have Coleco Gemini? I am doing some maintenance work on mine. The original TV to Game switch thing seems to produce a very noisy picture. 80% of the dots are randomly white so I can’t see anything. I tried with a NES switcher but it is still way too noisy. I tried with a SEGA Genesis switcher but it is still way too noisy. Quote Link to comment Share on other sites More sharing options...
OldSchoolRetroGamer Posted September 9, 2021 Share Posted September 9, 2021 Those type of switcher will always produce snow and grain with older systems of the Coleco Gemini era (ColecoVision, 2600 etc) as the signal does not fully support the auto switching built into those types. IF your original manual switch type is producing grain you should just try with a RF to coaxial adaptor, they bypass the need for the Game switch and connect the cord directly to TV input. Does the Coleco Gemini have a channel select switch on back? Make sure it is set to the same channel you are attemting to tune it to as well. Example RF TV Coaxial F Plug Female Adapter https://www.amazon.com/RFAdapter-Connector-Convertor-Commodore-Colecovision/dp/B07VWQF6WS/ref=pd_lpo_1?pd_rd_i=B07VWQF6WS&psc=1 Quote Link to comment Share on other sites More sharing options...
rietveld Posted September 9, 2021 Share Posted September 9, 2021 6 hours ago, OldSchoolRetroGamer said: Those type of switcher will always produce snow and grain with older systems of the Coleco Gemini era (ColecoVision, 2600 etc) as the signal does not fully support the auto switching built into those types. IF your original manual switch type is producing grain you should just try with a RF to coaxial adaptor, they bypass the need for the Game switch and connect the cord directly to TV input. Does the Coleco Gemini have a channel select switch on back? Make sure it is set to the same channel you are attemting to tune it to as well. Example RF TV Coaxial F Plug Female Adapter https://www.amazon.com/RFAdapter-Connector-Convertor-Commodore-Colecovision/dp/B07VWQF6WS/ref=pd_lpo_1?pd_rd_i=B07VWQF6WS&psc=1 That is how I connect my Gemini also 2 Quote Link to comment Share on other sites More sharing options...
copperboy Posted September 10, 2021 Author Share Posted September 10, 2021 Is that just a connection (just a conductor) or is there a resistor or a circuit inside? Quote Link to comment Share on other sites More sharing options...
rietveld Posted September 10, 2021 Share Posted September 10, 2021 12 minutes ago, copperboy said: Is that just a connection (just a conductor) or is there a resistor or a circuit inside? Straight pass through 1 Quote Link to comment Share on other sites More sharing options...
mr_me Posted September 10, 2021 Share Posted September 10, 2021 What cable are you using? It should be RF shielded. A regular AV cable will give you a noisy picture. Quote Link to comment Share on other sites More sharing options...
copperboy Posted September 11, 2021 Author Share Posted September 11, 2021 16 hours ago, mr_me said: What cable are you using? It should be RF shielded. A regular AV cable will give you a noisy picture. I tried the original Coleco switch + AV cable since somehow I misplaced the original RF cable. I don't know what the internal of the AV cable is like. I think the AV cable is 3 mm to 4 mm in thickness. For the NES and Sega Genesis switcher thing, the RF cable is integrated. I think they are 3 mm diameter. Quote Link to comment Share on other sites More sharing options...
NIAD Posted September 11, 2021 Share Posted September 11, 2021 Get yourself an RF Cable (preferably an old one as I have had varying degrees of success with new ones) and the RF-Coaxial Adapter. Quote Link to comment Share on other sites More sharing options...
copperboy Posted September 14, 2021 Author Share Posted September 14, 2021 I would have to see if there is a better cable and that adapter at my thrift store or electronics store. I did a temporary connection with a cable TV coax cable. The image looks pretty clean. Woohoo! 1 Quote Link to comment Share on other sites More sharing options...
rietveld Posted September 14, 2021 Share Posted September 14, 2021 11 hours ago, copperboy said: I would have to see if there is a better cable and that adapter at my thrift store or electronics store. I did a temporary connection with a cable TV coax cable. The image looks pretty clean. Woohoo! I agree that using a thick coax cable with the RCA adapter will provide a cleaner picture than using a RCA cable with the coax adapter Quote Link to comment Share on other sites More sharing options...
leaded solder Posted September 15, 2021 Share Posted September 15, 2021 My Gemini looked best with a cable-TV coax cable (very thick, hard to bend) and the RCA-to-F-type adapter linked above. If you do open it up, look for broken solder joints on the controller connectors - both of mine were bad, as was a crack developing on the joints for the DC jack. Quote Link to comment Share on other sites More sharing options...
copperboy Posted September 19, 2021 Author Share Posted September 19, 2021 On 9/15/2021 at 2:36 PM, leaded solder said: My Gemini looked best with a cable-TV coax cable (very thick, hard to bend) and the RCA-to-F-type adapter linked above. If you do open it up, look for broken solder joints on the controller connectors - both of mine were bad, as was a crack developing on the joints for the DC jack. Yes, the controller port of controller 1 had a problem long ago when I had the Gemini for a few years (1985?). I think since we insert and remove the controller often, it flexes and develops a crack in the metal. This was fixed. Port 2 is fine since I never used it. Quote Link to comment Share on other sites More sharing options...
rietveld Posted September 20, 2021 Share Posted September 20, 2021 On 9/19/2021 at 12:17 PM, copperboy said: Yes, the controller port of controller 1 had a problem long ago when I had the Gemini for a few years (1985?). I think since we insert and remove the controller often, it flexes and develops a crack in the metal. This was fixed. Port 2 is fine since I never used it. I needed to re flow both of my joystick ports also Quote Link to comment Share on other sites More sharing options...
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