Sega Genesis VA2 Board Rev. SMD Component Replacement - Page 1
Forum section: electronics / repair

author: DHeth
author_rank: Newbie
timestamp: August 22, 2016, 03:22:44 am
content: Hello, I'm pretty new to electronics repair and I've been repairing Old Video games consoles mostly. I have been able to fix everything so far but I'm stuck on this one.I have a Sega Genesis VA2 Board Rev. that outputs garbled video, the sound output is fine.https://goo.gl/photos/JxpuiPovkzVbCTSU7I went inside to look for for bad solder joints when I discovered this :https://goo.gl/photos/oqYceUjPzATbUrmy8the small (light beige) ceramic component in the picture. It appears to be chipped in half, or blown do apart ? can these explode?(zoomed out)https://goo.gl/photos/z4nwXXsQkXuBfdKj6It think it is a surface mount ceramic capacitor but I'm not sure. I'm hoping replacing this part fixes it , however I can't identify it to know the specifications to buy a replacement part.http://www.mouser.com/Passive-Components/Capacitors/Ceramic-Capacitors/_/N-5g8m/This is the first part I have had to replace that is not labeled or easily identifiable.I tried following the traces on a schematic but one of the pcb pass throughs was underneath an IC and I could no follow it.http://gamesx.com/wiki/lib/exe/fetch.php?media=schematics:genesis-2-md-2-schematic-va1-1_of_4.png

author: nidlaX
author_rank: Frequent Contributor
timestamp: August 22, 2016, 03:33:52 am
content: You should look at the circuit board layout diagram in the service manual, find the identifier for that capacitor, and then match it to the correct part on the parts list. The layout diagram will show where each part is located precisely on the PCB.

author: DHeth
author_rank: Newbie
timestamp: August 22, 2016, 03:57:16 am
content: that one diagram is all I have been able to find for the Sega Genesis MK1 and I'm not even sure it is the correct board revision.For some reason I can find plenty of Service manuals for the Sega Genesis MKII thoughWhat are the primary specifications needed for choosing a new Capacitor, Capacitance and voltage?The capacitor I'm looking at replacing:It issurface mount.It isceramic.I don't think it ispolarized.Voltagerating? As long as i'm equal to or higher than the original I'm ok ?Capacitance? There is probably no way to measure the capacitance since the part is damaged.I'm not sure what changing the capacitance rating does, too low and It can't store enough energy? Too high and it ____ ?I found this list of all the electrolytic(only) capacitors in the Genesis Mark 1 VA3, not really helpful since it doesn't list the ceramic capacitors though.LabelVoltage Rating (V)Capacitance (uF)----------------------------C1 16 220C13 16 10C23 10 100C24 10 100C30 16 10C31 16 10C32 10 220C38 16 10C4 10 100C40 50 1C41 10 10C42 50 1C43 16 10C44 50 1C49 10 100C5 16 10C50 10 220C51 10 220C52 10 100C53 10 100C55 16 10C57 16 10C58 50 1C59 16 47C60 16 47C61 50 1C62 50 1C63 16 47C64 16 10C65 10 47C66 10 47C67 10 47C68 10 47C71 16 10C72 16 10C74 10 100C79 16 100C86 10 100JP1 10 47

author: CJay
author_rank: Super Contributor
timestamp: August 22, 2016, 01:26:54 pm
content: They generally don't explode, looks like mechanical damage.If that were my board I'd remove the other pale beige capacitor and measure it.

author: DHeth
author_rank: Newbie
timestamp: August 23, 2016, 02:50:34 am
content: Looks like I get to learn a new function of my (junk)multimeter , it has two sockets on the FCx setting for capacitors. I take it the capacitor has to be isolated to get an accurate reading of capacitance .I know replacing the capacitor with a higher voltage rated one is ok.What are the drawbacks if I exceed the capacitance of the original capacitor, it will draw more voltage initially to charge it up ?