Sega Master No power but was working

[libernullmal]

I have the Sega Master System 3010 model and originally bought from some guy on e-bay for 20 dollars and he said it didn't work.. hooked it up and set it up and tried Miracle Warriors which I had bought because of the great deal I found it for at a flea Market. Well today I was playing Miracle Warriors (I haven't learned to save yet ) and all of a sudden the screen went black but the system was still on showing a green light. Thought it was the Video so I messed with the plug still nothing. So I tried the unplugging the power and the video and when I hooked it back up it would not start.

I read on a posted subject on this forum from Jobocan's that it could be a resistor but as I've never done this before how would I know which resister it is? I work at a valve and instrument repair shop so I know a good couple of people who are electronic repair/ soldering smart and savy and they have been meaning to show me the ropes. But just to make sure what would be the best approach to this?

[sin2beta]

Jobocan might be able to give more specifics, but I can give you some resources for the worst case scenario that it is something else.

After much drama, ebay bidding, and such. SMSPower obtained and uploaded the service manuals for the master system and game gear. Here is the HTML version of the master system manual (just 3 weeks old)

http://www.smspower.org/Development/SegaMasterSystemServiceManual

Do you have a Genesis model 1? The simplest thing will be to try that AC adapter and AV cable. A lot of times, that fixes what you describe. Also, I have purchased several "as parts" items from ebay and just after a good cleaning inside, they work perfectly. Some people seem to bury their game systems in dirt and cigarettes before playing them. One time I found a buck in change in a Genesis!

I would do the above first no matter what. Always clean them out. Then troubleshoot using the service manual.

[libernullmal]

thank you sin2beta,

 I did check out the inside this thing is super clean.. no dust bunnies or anything.. checked for leaks or inploaded caps but nothing. But now I have the service manual I will go to work tomorrow on some of my own time and see what a co-worker says about it with the multimeter.

[htimreimer]

the switch for the power button could be gone or it could be a blown fuse

look at the switch for the power button and look for rust on the switch also look for burn marks on,around and on the solder connection for the switch

look for a fuse and if you find one look for burn marks or something like this

[tpugmire]

It shouldn't be the fuse if the power light is still on. You mention the screen going black, but is there still sound?  It almost sounds like a power problem. My money is on the voltage regulator (7805, I think).

[libernullmal]

after I had unplugged it and replugged it and tried to turn it on it wouldn't turn on no green light no sound. I then tried replacing the power adapter with the one that goes to my segaCD which so happens to be the same MK-1602 power brick per http://www.gametrog.com/GAMETROG/How_which_do_i_need_SEGA_AC_Power_Supply_Information_Specs_Model_mk-3025_mk-1602_mk-2103_mk-1479_mk-4122_aa-s95j.html no go still . When I took it apart I didn't see any burn marks or anything the board was pretty clean. Then Unfortunately the guy I was going to have help me check this out on wasn't in today so I will have to wait till tomorrow.

[tpugmire]

If you aren't getting any power, then it is most likely the fuse.

[libernullmal]

I will look for the fuse but the last time I looked I didn't see it anywhere.

[htimreimer]

I will look for the fuse but the last time I looked I didn't see it anywhere.

type "different types of fuses electrical" in to google images and see what you can find

[pceslayer]

There should be a voltage regulator marked 7805. Test it to see if you are getting 12v on one end and 5v on the other. If you are not getting the 5v replace the regulator.

Set your multimeter to DC and with the SMS plugged in and powered on connect your black probe to ground anywhere on the mother board(a screw) and use the red probe to touch the outer legs of the regulator. I do believe the left leg on the regulator is VI(voltage in) and should be at around 12v and the right leg is VO(Voltage out) and should be 5v (center leg should be ground).

[libernullmal]

It is back up and running again. I think what happened was that the thermal compound between the heatsink and the 7805 voltage regulator had dried out and pretty much burned out because of all the heat it produced. Replaced and it worked great. though because of some issues I had to make minor change to the heatsink and the Aluminum Shield that goes on top. But when I was done it worked just like the old one... The bad thing is that I read that their were a couple of sega systems with a game on the board. This one of course didn't come with any

[pceslayer]

Every Master System came with at least one game.

Power on the system with no cart and at the "Enjoy!!!" screen hold down buttons 1 and 2 and then press UP.

Enjoy!! lol

[libernullmal]

I will check that out pceslayer, and thank you to everyone who helped me. Including the guy who showed me the soldering and de-soldering of things