Jeremy Popp Posted June 16, 2013 Share Posted June 16, 2013 I'm not getting any responses on SegaAge, so I thought I would post here. Just picked up a 2nd Sega Master System (model 1) at the flea market and I'm having a strange issue. The images on the left are of the "bad" system, and on the right show my other system. As you can see, the colors seem off and/or oversaturated. The difference is actually less noticable than the images would lead you to believe. If I didn't have a second console to compare it to, I would assume that's just how they look. I've tried various av plugs, composite and RF with the same results. Unit seems to play rather well with no other issues. I reflowed all the solder joints that are related to video (at least I think). Do some SMS's have different video parts, and maybe this is normal? Anybody have any other ideas? Thanks! Quote Link to comment Share on other sites More sharing options...
Uzumaki Posted June 18, 2013 Share Posted June 18, 2013 Worn caps? Electrolytic caps do fail without showing obvious sign. I recently recapped one of my Intellivision that didn't show any visible bad cap but had crappy video. One of the cap had ESR over 10 ohms and 0.086uF (label said 100uF) Quote Link to comment Share on other sites More sharing options...
Jeremy Popp Posted June 18, 2013 Author Share Posted June 18, 2013 Worn caps? Electrolytic caps do fail without showing obvious sign. I recently recapped one of my Intellivision that didn't show any visible bad cap but had crappy video. One of the cap had ESR over 10 ohms and 0.086uF (label said 100uF) Thanks, I wasn't sure if a bad capacitor could lead to this or not... I'm kinda new to electrical engineering, and game repair/modding. I ordered a cap kit, so hopefully that will solve it. Thanks again for the reply. Quote Link to comment Share on other sites More sharing options...
Jeremy Popp Posted June 19, 2013 Author Share Posted June 19, 2013 I just did a complete cap replacement, and it made no difference. Still looks the same. Does anyone have any other suggestions? Quote Link to comment Share on other sites More sharing options...
bust3dstr8 Posted June 20, 2013 Share Posted June 20, 2013 (edited) That problem looks more resistor based. I couldn't find a SMS schematic, but the V7040 datasheet has an application NTSC circuit to reference. http://www.datasheet...0_Sony.pdf.html Edited June 20, 2013 by bust3dstr8 Quote Link to comment Share on other sites More sharing options...
Jeremy Popp Posted June 20, 2013 Author Share Posted June 20, 2013 I just cataloged and verified all resistors are within thier proper range using a multimeter. Thanks for the advice though and that link. Quote Link to comment Share on other sites More sharing options...
bust3dstr8 Posted June 20, 2013 Share Posted June 20, 2013 (edited) As things age the tolerances may drift out of spec. Your resistors may still be good, but other components may not. I just did a dual bios for my SMS1 and since it was open I checked the Chroma resistor. It is a 620 in the SMS, but the datasheet calls for a 1K. You could try upping resistance on the Chroma or Blue inputs and see what happens. From your pictures it looks like Blue is main color being overdiven. Edited June 20, 2013 by bust3dstr8 Quote Link to comment Share on other sites More sharing options...
Jeremy Popp Posted June 25, 2013 Author Share Posted June 25, 2013 I tried doing some more research, and I have a lot of various schematics, but I think this problem is over my head. Thanks for the help - if anyone has any interest in buying it, send me a PM - or maybe I'll give it another try when I've developed my skills more. Quote Link to comment Share on other sites More sharing options...
zylon Posted June 25, 2013 Share Posted June 25, 2013 Does your saturation level change with time if system is left on? I had one with a bad regulator that did that. Quote Link to comment Share on other sites More sharing options...
Jeremy Popp Posted June 25, 2013 Author Share Posted June 25, 2013 Does your saturation level change with time if system is left on? I had one with a bad regulator that did that. Thanks for the suggestion, I just left it on for the last 45 min with no change. Good thought though... Quote Link to comment Share on other sites More sharing options...
Greg2600 Posted June 25, 2013 Share Posted June 25, 2013 Could try master system forum on sms-power.org. Quote Link to comment Share on other sites More sharing options...
ApolloBoy Posted June 27, 2013 Share Posted June 27, 2013 What TV are you using and what video encoder does the "broken" SMS have? Quote Link to comment Share on other sites More sharing options...
+FujiSkunk Posted June 27, 2013 Share Posted June 27, 2013 (edited) A long shot, but check that the power jack is supplying adequate power to the system, and maybe also try the "bad" system with the "good" system's power supply. I had an Atari 7800 that had similar video issues when I tried to use a universal power supply that didn't provide adequate power. (To those who are suddenly wondering how one can use a universal power supply with a system that has a decidedly non-universal power jack, let's just say it wasn't easy.) Edited June 27, 2013 by FujiSkunk Quote Link to comment Share on other sites More sharing options...
Jeremy Popp Posted June 28, 2013 Author Share Posted June 28, 2013 Using samsung plasma tv for both systems, using same original 3025 power supply for both systems. 'Broken' sms has the sony cxa1145 Quote Link to comment Share on other sites More sharing options...
Osgeld Posted June 28, 2013 Share Posted June 28, 2013 whats the resistance between the outside of the composite jack and the inside while unplugged from the tv Quote Link to comment Share on other sites More sharing options...
Jeremy Popp Posted June 28, 2013 Author Share Posted June 28, 2013 whats the resistance between the outside of the composite jack and the inside while unplugged from the tv Just to be sure, I assume you're talking about the Input for the RF box on the rear of the unit? if so, it's 80Ω Quote Link to comment Share on other sites More sharing options...
Osgeld Posted June 28, 2013 Share Posted June 28, 2013 yea, it should be 75 but 80's more than close enough for tv welp I am out of idea's short of hooking it up to a scope Quote Link to comment Share on other sites More sharing options...
ApolloBoy Posted June 28, 2013 Share Posted June 28, 2013 'Broken' sms has the sony cxa1145 And the working one? SMSes with the CXA1145 have pretty terrible composite video while the earlier ones with the V7040 are a little better in that regard. Quote Link to comment Share on other sites More sharing options...
Jeremy Popp Posted June 28, 2013 Author Share Posted June 28, 2013 And the working one? whats the resistance between the outside of the composite jack and the inside while unplugged from the tv I just checked my good system, and I got a reading of 262Ω, it has the Sony V7040 - maybe that's why. Quote Link to comment Share on other sites More sharing options...
0078265317 Posted June 29, 2013 Share Posted June 29, 2013 Just adjust the tv brightness and contrast nobody will ever know. Quote Link to comment Share on other sites More sharing options...
Jeremy Popp Posted July 10, 2013 Author Share Posted July 10, 2013 And the working one? SMSes with the CXA1145 have pretty terrible composite video while the earlier ones with the V7040 are a little better in that regard. This might actually be the case. I did a test using a different TV - a LCD, and the results are below: Again, left side is "bad" SMS, and right side is my good one. Left side has the sony cxa1145 chip and right has sony v7040. There is almost no difference. My question then is, if I were to sell or trade my "bad" sms, does it qualify as bad? After this test, I think it's just a matter of different chips on a newer TV. CRT TV's would probably not show a difference either. Thanks! Quote Link to comment Share on other sites More sharing options...
+FujiSkunk Posted July 10, 2013 Share Posted July 10, 2013 I wouldn't call it bad, especially if the results are consistent from game to game. Like 0078265317 suggested, the worst anyone will have to do is fiddle with their TV controls a bit. Quote Link to comment Share on other sites More sharing options...
ApolloBoy Posted July 11, 2013 Share Posted July 11, 2013 You could also try modding it for S-video or use RGB through a SCART to component converter. Quote Link to comment Share on other sites More sharing options...
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