nesdev.org

I'm sorry for posting a topic out of nes stuff
I bumped into a terrible problem....There is a weird sound and black screen like on the following video when I switch it on :
http://www.youtube.com/watch?v=_rE2e-GbTFs

And I noticed the following :-
1-The longer I keep it switched on , the more it functions properly and the problem slightly solved (the sound volume decreases).
2-When I switch off the devices and the electronics that consume much electricity , it functions properly and the problem slightly solved.

And these are the images of the board from the front and the rear part :

bottom left


bottom right 1


bottom right 2


center left


center right


Top left


Top left (clearer)


Top right


Top right (clearer)


whole board


I'm really confused where the problem is
BTW the reset button doesn't work till I press it strongly several times...and I'll keep the rear part images till it's necessary to diagnose the problem
and I'm sorry for posting many pics.

They are known for horrible capacitors.

The horizontal stripes and hum are pretty good indicators that your AC adapter isn't providing enough power. Try using another AC adapter (10 volts, at least 0.85 amps, positive tip) and see if that fixes it.

I just want to point out that this is a clone system...

Whoops, I guess I missed the complete lack of Sega logos.

I still think there's something wrong with the power supply.

3gengames wrote:They are known for horrible capacitors.

tell me plz where exactly the capacitor is..and why don't u suppose the ac adaptor is the problem source?

Joe wrote:The horizontal stripes and hum are pretty good indicators that your AC adapter isn't providing enough power. Try using another AC adapter (10 volts, at least 0.85 amps, positive tip) and see if that fixes it.

yes I agree with u but why the problem isn't the capacitors like 3gengames said

ouso1999 wrote:There is a weird sound and black screen like on the following video when I switch it on :
1-The longer I keep it switched on , the more it functions properly and the problem slightly solved (the sound volume decreases).
2-When I switch off the devices and the electronics that consume much electricity , it functions properly and the problem slightly solved.

Everything you've described is consistent with using too small of a power supply. What are you currently using? Try using something capable of providing more amperage. (And, depending, maybe more voltage. What's written on the two parts in TO-126s in the big metal heatsinks to the left of the cartridge slot?)

BTW the reset button doesn't work till I press it strongly several times...

Sounds sticky to me. How much has this console been used? (I see it was manufactured in 1994)

mikejmoffitt wrote:I just want to point out that this is a clone system...

no I don't think so for these reasons
1-it was made in japan
2-it has a manual in many languages including arabic.
3-I have the original controllers and the ac adapter till this day and they're featured with their long age and strength and they still work after several times of falling and abuse (unlike the clone ones which are featured with weakness) except the ac adapter 'cause they fell several times and btw it was bought it for more than 17 years.

I don't have enough experience in this suff so could u tell me how u knew that it's a clone..may be I'm wrong

lidnariq wrote:Everything you've described is consistent with using too small of a power supply. What are you currently using? Try using something capable of providing more amperage. (And, depending, maybe more voltage.

i'm using this ac adapter
input:220VAC 50HZ 14W
OUTPUT: 10V DC 850mA MAX

What's written on the two parts in TO-126s in the big metal heatsinks to the left of the cartridge slot?)

I don't know which place u mean?do u mean the two parts below the cartridge slot?

Sounds sticky to me. How much has this console been used? (I see it was manufactured in 1994)

Resest button doesn't work at all now even after pressing it several time.
My brother bought it for approx 17 years , but I maintain it and use it a little.
where is "1994" written?

Joe wrote:Whoops, I guess I missed the complete lack of Sega logos.

do u mean it's clone?..BTW it's mega drive not genesis.

That thing is 100% definitely a clone, but what is called a superclone that uses exact copies of the original chips (same pinout too !).

And what you experience is definitely too weak power supply. You need at least 1A (the more the merrier) and more than 7V (but less than 18V).

TmEE wrote:That thing is 100% definitely a clone, but what is called a superclone that uses exact copies of the original chips (same pinout too !).

And what you experience is definitely too weak power supply. You need at least 1A (the more the merrier) and more than 7V (but less than 18V).

but as u see what I described above..the adapter is 10V namely more than 7V , so how is it too weak?
and where "1A" is written on the adapter?I can't find it.

ouso1999 wrote:do u mean it's clone?..BTW it's mega drive not genesis.

It's both a Mega Drive and a Genesis!

Yes, it's a clone. A real Mega Drive/Genesis would have the Sega logo silkscreened on the PCB and a few of the ICs. I've found some pictures here if you'd like to compare your clone to real Mega Drive hardware.

The clone looks like it uses Mega Drive 1 parts in a Mega Drive 2 form factor. Maybe the chip manufacturers didn't anticipate Sega changing the board layout?...

ouso1999 wrote:but as u see what I described above..the adapter is 10V namely more than 7V , so how is it too weak?

Because it's broken.

The brick can be 20V too but if it only gives out 0.1A it will not be able to do anything. The brick you have probably does put out only about 500mA, and at that point voltage drop is so great it has problems keeping power regulators operational. There's maybe 6V left when you go and measure the brick output while the system runs.