Hey Guys,

I just received a Sega Master System. When I plug it in (either using the AV cable or RF) all I get is a blank screen. Reset or Pause does nothing. The system came with the original cart of
Hang On / Safari Hunt. Sometimes it'll also show a vertical rainbow of colours and then go black.

I've checked the solder on the backside and even re-fluxed/soldered the card connector. Everything looks good and the power led lights up.

Any assistance would be GREATLY appreciated as I've always wanted one of these things but never ever got one (grew up on Intellivision then to Sega Genesis).

Thanks in advance!!!

PS even if cartridge is out, same screen displays, no mention of SEGA anywhere.

The standard questions:

1.) Have you tried using different games besides Hang on/Safari one?
and
2.) Is the cart slot itself/cart free of any dust and/or corrosion?

1. Nope. I only have that cart. Shouldn't the reset cause the screen to flicker at all thou? I'm trying to get a read on what the issue is.
2. Both look pretty good. I took a slight emery cloth to it and very lightly rubbed both sets of contacts.
- Now I was able to see a title screen out of adjusting the cart and rebooting the console. Out of 60 resets and adjustments, Title came on 2 but then wasn't playable.

Any other ideas? I don't have a oscilloscope but I do have a DVM and the power looks to be ok. I've even tried 2 different power supplies.

I don't think the cart slot is the issue. Most (if not all) Master Systems came with a game built into the system, so even if the cart slot was bad it would boot the built-in game. I think one of the chips on the motherboard is bad/loose. Take it apart and press random things on the board with the power on to see if you get video. I had a genesis once that only worked if I put a lot of pressure on the case. Eventually I got tired of balancing 6 or 7 books on top of it so I opened it up and pressed my finger on all the chips and I found that one was loose, and I had to surface mount resolder it back on. It sounds rudimentary but I guess sometimes the pins one chips can get shifted and don't make proper contact anymore, and your adjustments of the cart are putting slight pressure on the area.

[quote="wallydawg"]I don't think the cart slot is the issue. ...
...
I've just finished trying that and no dice. I've even gone as far and taking the game out of it's case and seeing that all contacts are moving in the cart socket.

I'm thinking it may not be a bad idea to re-solder the entire console to make sure no breaks are present. I've resoldered the Cart socket... Can't hurt, can it? I'd be using a no-clean solder pen. Solder with lead .

-edit-
Just finished resoldering all IC connections. Still sitting at black screen. Dunno, maybe time to go to Sega Heaven!

Is there sound?

Sorry I forgot to mention. No sound unless it's one of the screens that is locked up as a solid colour and a single tone. Nothing like a game in the background or even the SEGA startup sound...

Thanks for the questions/ideas!!! Maybe we can figure this thing out!

Can you check the voltage at the CPU?

5 volts exactly. If I could only get my hands on a repair manual. I've checked a few areas for schematics and found one but it differs slightly. <pulling hair out>

It sounds like your Master System's BIOS might be corrupt. I don't exactly know which chip on the motherboard holds the BIOS, but if I were you, I'd replace the BIOS chip. Could you open up your Master System and take a picture of the motherboard so I know which of my Master Systems to take apart and locate the BIOS chip?

How can I get the pics to you? I took 6 of them and they are a total of 1.4 Mb. Every pic I try to add it either says too big or quota has been reached...
Model # 3010.
The Board has numbers on it. SEGA M4 / 837-6405 / POWERBASE/NTSC

There are 2 chips that mention SEGA on them.
#1 - 42 Pin, SEGA 315-5216,120U,8739 Z43 (Located near controller ports)
#2 - 64 Pin, SEGA 315-5124, 2602B 81 04 88 B (Located near 2x NEC Japan/D4168C-15)

Other chips present:
#3 - NEC 8705PX206,D4168C-20 (Located beside MPR/Sharp)
#4 - MPR-10052, SHARP JAPAN, 8804 B (Located beside Zilog/Z80)
#5 - Zilog, Z0840004PSC,Z80 CPU,8748 SL0965 (Located Near RF and 8Pin outputs)
#6 & #7 - NEC Japan, D4168C-15, 8747P5016 (Located by Power button)
#8 - Sony 7X03, CXA11045 (Located by RF and 8Pin outputs)

Hope this makes sense! Thanks again for your help!!!

Looking at the bottom I see the Sega Support number. I guess she'd be out of warranty by now.. I wonder what 24yrs of warranty would cost?

If it is a SMS 1 then there is no built in game im sure.

SMS 2 has one. Alex Kid in Miracle World.


If you got picture once, then the cartridge slot must be coroded.

If not, then the AV 'box' must be faulty. I know my cousins was. It was like a metal tin and when I opened it, the wire was snapped off.

It's a SMS 1 from what I can tell with the youtube vids out there. Case measures approx. 14" by 7" and has the power trangle diagram on the top.

The AV box couldn't be the issue thou because I've tried both outputs and there is no difference (RF and 8 Pin output(Red/White RCA))... Right?

What is meant by 'corded'?

You could upload the images to ImageShack then link to them.

Although with the information you've provided, I might have an idea what chip on your Master System holds the BIOS. I'll have to find the pinouts for the chip before proceeding any further.



Haunted360 meant "corroded." But that wouldn't make a difference if the SEGA screen doesn't show up. It sounds more like your Master System is suffering from BIOS corruption than anything else.

EDIT: If your BIOS is truly corrupted, you can completely bypass it until you get a new ROM to replace the faulty BIOS. Follow this BIOS removal guide and you should be able to play your Master System games without a BIOS: http://www.smspower.org/Development/BIOSRemoval

Here's the pinout of the Master System's cartridge slot: http://www.smspower.org/Development/SMSCartridge

If this fails, the BIOS is fine and another component is broken.

I'm unfamiliar with ImageShack. I'll look into it and post the images since looking at the page you gave me, I couldn't really be certain of the exact pin as it doesn't mention the bios specifically. I did notice the I/O chip is the same as mentioned on the page.

Is it possible to assume the 315-5124 (64 Pin IC) is the bios and pin 20 is the one to disconnect? I worry about the word assume thou, eg. ass/u/me .

Hope to have the pics on later tonight.

Thanks again for everyone's interest!!!