Master system has stopped working. Possible fix?

My second post in as many days.

I have a Master System (first version with card slot) and it was working perfectly. However, I went to plug it in a day or so ago and there was no picture. The power light came on, but no image or sound. I was trying to record through my HD PVR and thought that it may not be playing ball, so I plugged it directly into the TV. Still no image or sound. I tried a couple of different leads but nothing. As I said, it was working less than two days before, but now, only power.

I tried my Xbox through the PVR using the same connections etc and that works fine, so it's not that. Either the componant leads I tried, the RF lead, or the system. Looks like the system I reckon.

Does anyone have any ideas?

 

Hi,

First a good cleaning of the cart slot and the console is a good start.
Open the poor thing et look if there's any leaking capacitors. Changing them all could be a solution.
You also have to check there's a correct voltage from the voltage regulator (MC7805)

 

Could be a blown fuse. I Damaged a famiclone once just by touching it. Had the same problem, power light is on, but no video. Replacing the fuse fixed it.

 

The SMS doesn't have a fuse, so if the wrong PSU is used the 7805 is usually the first thing to go.

 

Thanks for your reply. What would you say is a good was to clean the cart slot? Isop-alcohol? Any tips on how to do it?

I#ll open it up later and see if it looks like anything has blown.

 

Yes isopropyl alcohol. You can use stuff Deoxit or Kontakt 60, or stuff for cleaning electronic contact which are the same thing but with other stuff in it like lub.
You can use the credit card method: spray or pure some alcohol in the cart slot, then put your credit card (or any rigid piece of plastic, thin enought to not bend the pins in the slot) then go in/out multiple times. Wipe the excess of alcohol on the mother board, Re-pure some alcohol, and repeat.

I use Kontakt 60 and a toothbrush: I spray in the slot, brush gentily as deep as I can, wipe the excess, and do it again. Most of the 2 or 3 times are enought. Got some old Megadrive back to work like that, and my SNES now popping games 100% of the time.

 

Here's a question, what TV are you using?

 

Cleaning the cart slot isn't going to do anything if the built-in game doesn't work. Have you tried running Snail Maze?

Component leads? Do you mean composite?

Check the output of the PSU and check voltages on chips are correct, for starters. I would have thought a blown regulator (you didn't use a NES PSU, did you?) would result in no light, but it's worth checking. It's possible there's a dry joint somewhere.

 

Thanks for the reply chaps. Just using a composite cable....yellow and white plugs. As I said, two days before I plugged it in and it worked fine. Went to record another video through the PVR and it just wasn't working. No picture or anything. Didn't work plugging directly into the TV either. No snail game, nothing.

Used the MS PSU that came with it, so no....no NES PSU

Ok. Opened it up an tested it all out again. Light still comes on, and still no picture. I've looked around and cannot see anything untoward as I did in my Dreamcast in the other thread (but admittedly I'm not sure what I'm looking for). Managed to locate the 7805 as apolloboy suggested, and I dunno....should it be like that? Looks like ther eis something chalky or limey behind it.

 

Do you have a multimeter?
If so, You should test the 7805 and see if it's doing his job.

You must have something like 9/10v on input and 5v on output. If not, your 7805 is dead.

Dead caps are either leaking and/or starting to buldge on their top. But a dead caps is not always visible. By default I tend to replace them.

I had a special case with a Megadrive model 1 which didn't always boot: turns out the small PCB where the DC connector has a corroded trace one the (+)


If nothing changes, then you have to go the long way: test the traces from the DC connector by following the path of the power (+) and (-) to see where it stops.

Sorry for not being much more helpfull :/.

 

No, that's a great help mate. I don't have a multimeter, but seeing as how I want to get into some modding and repairs I can see i'll need one. I Don't know if i'm jumping the gun and it may just be a broken lead. I did try both composite and RF though. I may just get another lead and test it that way. Then again, I guess there will be no harm replacing the 7805 anyway and get some practice with soldering etc (never done it before)

 

Had one with a similar issue. I bought it as faulty, recieved it and the ROM had been cut out with what appeared to be nail clippers lol. I had to "flywire" it back in. It didn't work. Tried re-capping, no go.

On closer inspection 2 traces had corroded going to the Z80. Bridged or re-run the traces and BAM! off she went. Tough little boxes of sparks the old Master Systems....

 

It's on a heatsink because it gets hot. That's thermal paste.

You would benefit greatly by learning some electronics basics for starters. I'd recommend picking up a book - something like the For Dummies range is a good way to get started easily. And yes, you need a multimeter as voltage checks would be your first port of call.

I've merged some of your posts to tidy the thread up a bit. If there hasn't been a reply, try to use the edit button. If you're quoting multiple posts, tick the multi-quote boxes.

 

If you're suspecting the ROM is bad, you can "bypass it" by cutting the trace on it's "chip select" pin and connecting it to +5v. Then you take the trace which comes from the "controller chip" (trace which comes to the ROM chip and connect it up to the cart slot. You should find a detailed explanation on how to do it at SMS Power. They call that "TMS bypass" and that "hack" is used to make the SMS be able to play SG1000 games.


While that "kill" the back slot and the card slots as "bootable" slots it should at least allow you to test what is going on with the system to some extent.

But I'd toss a wild guess that your system has either a faulty clock crystal (it can be mechanically damaged by a strong bump or drop) if your system displays no video at all (TV keeps on "blue screen" mode).

Or if the TV goes black screen while the SMS power is on, it could have it's Z80 chip faulty/ damaged. Also an broken/corroded trace at any circuit which directly relates to the Z80 CPU could cause the SMS to black screen.

 

Thanks for the reply guys. I'm going to wait until I get some basic equipment and then I'll have a proper attempt. Apologies for all the questions, but we have to all start somewhere eh? I just feel bad chucking the system in the bin. I'd rather try to breath some new life into it.

I'll touch base again in a week or two when I have some gear and have read a bit.....hehe.