whats wrong with this master system?

i was at a local game store while i was on vacation and i bought a sega master system for 15$ with a controller. the case is in bad shape, the guy said someone dropped it while bringing it in and he couldn't sell it full price.

i plugged it in and nothing happened, so i took it apart to look at the motherboard to see if any caps are bad or something like that. there don't appear to be any signs of corrosion or anything. i tried hooking it up to a 2amp ac adapter that's 9volts and the master system needs 850 ma so i dont think its the psu. any idea why its not working? be kind of a shame to waste 10 bucks

 

Blown fuse, wrong setting on the TV, bad A/V cable, PEBKAC.

Take your pick. Need more information.

 

It could also be related to the PSU.

If you are using an unregulated PSU then you will not be supplying the correct voltage. Basically an unregulated 9v PSU @ 2amps will only provide 9v when there is a 2amp draw. If you are only pulling 850ma then the voltage will be a hell of a lot higher.

If you are using a regulated PSU - this doesnt matter, you can use any that meets the min ampage.

I had the same problem with my snes mine - 1.2a PSU was putting out too much power and was just giving a black screen - I changed to a regulated one or a genesis/megadrive psu and it worked straight away

 

Or 7805 reg.

 

not sure if it's regulated or not but its an adjustable one. it works fine on my sega cd. and i don't think it has anything to do with the a/v connections.

i have it hooked by rf and i hook my 2600 up that way too so that doesn't seem to be the issue. where would i find the fuse on the master system?

 

I'm not entirely sure there is a fuse on the SMS, but if you noticed I was trying to point out the problem is more likely to be a video, power, or other easily solved problem.

The power light should come on. Use a known good power supply, one that is tested on another SMS. Use A/V hookups that are also tested on a second SMS. There is no point in going into technical aspects until the basics are covered and checked.

 

i tried two different power supplies on it, both of which work on my other master system and my genesis

 

A thought, as this one happened to me.

The Genesis model 1 power brick is electrically and mechanically compatible with the Master System (at least the US model). The difference is that the Genesis brick has a much thicker plastic jacket at the tip. After many years of using one with my Master System the positive pin on the power plug separated with it's trace from the PCB.

I'd give it a check just in case. It'll be painfully obvious if it is a problem.

 

I have a PAL Master System II (the version which provides only the crappy RF output out of the box) and at the beginning I thought it wasn't working. Turned out I was using the wrong polarity! Most devices nowadays have center positive sockets, and on the tip which plugs inside them there is positive voltage inside the barrel and negative (ground) on the surface of the barrel. The Master System and the Genesis AC adapters on the other hand are center negative, and so the polarities are switched compared to what today is a de-facto standard. Owing to the good design of the Master System II board, unlike most eletrical devices nowadays, it didn't die in smoke, and I was able to rewire my AC adapter with the correct polarity. If you have a multimeter it's pretty easy to check the polarity, just put the positive probe (usually red for digital multimeters) inside the barrel and the negative (black) probe on the barrel surface, if something between -10 and -5 is displayed you're ready to go, and you can rewire your 9v AC adapter of choice - even many unregulated ones should work OK, because inside the SMS there is a voltage regulator which steps the voltage down to 5 volts (and should work with voltages from 5 to 10).
I don't know about other models of Master System and you could possibly have some faulty diodes due to the wrong polarity. Again a multimeter should help you sort that out.
EDIT: well, just now I see you tried with the right ac adapter. Still do check the diodes if there are any, though.

 

I wouldnt use a Genesis power cable on a Master system.