Sega Megadrive (Genesis) 2 (MKII) Repair (VA0) - Black Screen 

Looks like CA1 is a capacitor array on the data bus: gamesx.com/wiki/lib/exe/fetch.php?media=schematics:genesis-2-md-2-schematic-va1-1_of_4.png

+1 for Capacitor Array. 24:10 These are SMD version of LM324 opamp ;)

Thanks =D

Thanks lol =D

Yeah, I've seen a few Sonic carts faulty!

Thanks =D

Haha =D

That was a Quagmire "Giggity" moment.

=D Yeah, I love systems that use the 68K and Z80 =D

Haha :o)

Emmett Turner I'm glad I'm not the only one to notice this. I've got ten mds with damaged traces but not one with a dead chip. My sfc haul on the other hand have plenty of dead ppus.

Emmett Turner Maybe it could be due to people smuggling narcotics in the carts as well? :p What a strange day that must have been. hehe

Russell Brunskill Yep. Same can’t be said about copies of Sonic the Hedgehog though. Lots of copies of that game are dead (bad ROM chip). :( There’s a website out there where a guy does component-level repairs to Nintendo Super System arcade machines (SNES hardware inside) and the vast majority of the time it ends up being a proprietary chip (CPU, PPU1, PPU2, APU/SPC700, etc).

ElectronAsh LOL! Sure was. Guess I’ll never live that one down. :) It wasn’t the first time I found something interesting hiding inside an NES game (recorded myself finding a Xexyz prototype many years ago) but I doubt I’ll ever top that one. :) People at the flea markets keep telling me about “some guy who found heroin in old Nintendo games.” Their reaction is kinda funny when I tell them it was me. :) It really hits them when they realize how close to home it is. Heard it once on Friday and again yesterday. Next time I plan to pretend it wasn’t me and steer the conversation toward what an idiot “that guy” was for calling the police. ;)

I've seen loads faulty where PPU1 / PPU2 or the CPU die, but I would agree that I've not seen a 1 chip fail yet.

Thanks, will give that a try =D

Thanks =D Haha :o)

Thanks, very kind of you! All is good! Just run down with CFS at the moment! I don't really talk with Ms Mad Lemon tbh, or many other channels for that mater - I just never find a minute! She's been quiet on her channel since she got married, she's moving I think as part of that, but I am sure her channel will be back soon!!!

Let me know how you get on with it! Hopefully it can be saved =D

I will, going to take some time very bussy atm. Soon i get the time i will try and let you know :)

Yeah, lovely design =D I guess Nintendo did a similar thing with the Wii and GameCube - kind of making a super GC really, that way it would be backwards compatible.

Me too! They are so much more robust and reliable than the SNES. I think that's one reason they are so cheap - there's more of them surviving than the SNES, which means a flooded market.

Thanks =D When manufacturers design any electronic system, they are looking at reliability for say 2 to 5 years (sometimes longer depending on the system - eg. safety systems and security systems tend to be design to last decades!). So when a console is designed, if it lasts more than 2 years with very limited cooling - they will just sell it as is. Whereas with more cooling on certain components, it can very often make a difference where it lasts longer. Ultimately they will all die. I mentioned entropy and thermo dynamics a number of times now, and some people prefer to ignore it, but temperature is a factor in the life of any electronic component.

Thanks as always =D

I rather have the red buttons

The first thing to do (and you've probably already done it...) - reseat the flex ribbons (at both ends). Then clean and inspect the cart slot, and the part that fits into the Megadrive (pcb edge). Assuming that hasn't revealed anything, I next wonder if its a region thing... What region 32x games are they, and what region is your Megadrive and the carts it does work with when the 32x isn't connected?

@@GadgetUK164 so the region they are all megadrive pal games, console also megadrive and 32x is megadrive, what are these flex ribbons?? I will google it now! I thought it may have been a region issue so I double checked it wasn’t a genesis etc 🤣 last time I checked it after cleaning it isn’t even displaying the sega enterprise productions screen anymore just a black screen now hope it haven’t broken it even more. I checked the traces and they all link up to from the carts pins to the chips hmmm 🙈

The Highlander - I spotted it too, but assumed it would be fine (non-conductive). I learned something today! I was also feeling pretty smug for knowing the data bus traces needed to be matching lengths, so that was a nice little fix there.

Yeah, there was no electrical join - ie. measuring on continuity showed infinite resistance. It was just the fact they were so very close. If you look at how spaced out the traces are - there's a reason for such a large gap =D

It did get me thinking. Normally on a PCB traces are not a huge distance from each other. I wonder why it is that their signals never interfere with each other.

They can, and that's typically why there's a gap of a certain size between them. If you look at the close up on that particular zoom in where I added the two wires, there's quite a comparitively large gap between the traces (compared to their thickness). And to the left of that chip there you can see some traces that end abruptly between other traces (those are grounded, to stop interference with the traces next to them - audio outputs). On many boards (especially modern ones with 4 or more layers) there will be a ground layer usually under the traces too.

Haha, yes there are loads of Megadrives knocking around - it's amazing how people have held onto them and most of them have stood the test of time well!

Haha =D Yeah, that small overlap drove me nuts! What was surprising is that it didn't affect the Megadrive games at all... I use soft tissue =D But I know what you mean, microfibre is the best thing to use if you aren't sure! Thanks mate =D

A 7809 is a 9v regulator - chances are that has destroyed something on the board. Instead of providing 5v out, 9v has been fed into chips. They die with more than approx 5.25v typically.

Extension of the ground to isolate inbetween those traces! follow them to the left you can see they connect to the large ground plane area. EDIT: And it looks like its the audio ouputs going to the op amp on the left. Those grounded traces kind of act like a mini shield. Stopping noise getting onto the sound outputs before they go to the op amp.

How are you connecting it to your TV? I would try with a composite or RGB cable that plugs into the DIN socket on the back.

I think you're right!

Yes, you can try and resolder the connections holding the socket to the PCB on the underside, or you can swap the DIN socket (just need to find one with the same profile).

Thanks =D Yeah, does seem like something got spilled on there. Although, those 2 traces that needed patching - there was no corrosion or anything liquid looking - just black traces. Kind of looked like trace rot I spotted on the CPC I fixed.

:o) I wondered what you were on about, until I watched again. All I see now is me tapping things lol.

Once seen/herd it can not be unseen/unherd. :)

You make excellent videos^^ Though, "tap-tap" on your videos is... how to say... very #!@* xD Especially when english is not your native language like me ^^

Honestly not sure - I would start with a rivet kit from eBay or something and see if any in a kit would fit.

Thanks, very much appreciate it =D

Great idea =D

It could be a RAM fault! I have a similar Megadrive repair video coming up soon!

Awesome, looking forward to it... been on a massive Megadrive kick lately :-)

Thanks, yes MD1 audio wins =D Clear nail varnish sounds like what I should use =D

Haha =D

Hehe =D I much prefer the Mega CD 1 compared to the Mega CD 2 =D

I have never owned a model 1, But damn i love the look of it.

It was just an eBay seller at the time! These days, look at retrogamingcables.co.uk/ or Cool Novelties for cheaper cables.

=D

Good idea =D Chances are, whilst wet it will be conductive no matter what.

Thanks, yes - clear sounds best!!!

Yeah, don't get me wrong - I LOVE the SNES! But I have more nostalgia for the Megadrive =D

Maybe theres a capacitor leaking somewhere, perhaps in the cable?

@@GadgetUK164 That's the thing. I've checked all the caps and they're fine. I also use an HD Retrovision cable. The plastic on the connectors themselves seem to be "sweating".

It must be the connectors then =/

@@GadgetUK164 Hmm. At least in this video, you remove the pin connector. How do you go about removing the metal pieces? Do you have a video showing the process?

Also thanks for this - thanks to this video I was able to diagnose a broken link next to R80 and half a dozen broken links around the cartridge slot on the Megadrive 2 I have that isn't working. Not confident with the repair myself so I might find a friend I can work on it with.

Are you getting sound though? If you had sound but graphical issues, that would suggest VRAM. If it doesnt output sound and appears to crash with those blue vertical blocks, I am more inclined to thing work RAM or a VDP / arb fault.

@@GadgetUK164 No sound either. How straightforward a repair is it or am I better off sending it off for repairs. I'm trained as an electronics technician, but it's been years since I've used the skills, so I'm a little rusty.

If you've never done much desoldering of chips it could be tricky! You are best using a desoldering station or something to remove the IC. It can also be quite hard trying to source some spare parts too.

To me its a baby neo-geo, nothing will change that ;) But I accept it has a lot more in common with the arcade boards you mentioned there - certainly much closer spec'd =D

www.ebay.co.uk/itm/RGB-Cable-for-Sega-Mega-Drive-2-Genesis-to-TV-Scart-Lead/182768258528?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

:o) That hissing really did worry me lol.

It's not out of the realms of possibility, but more likely to be a dirty slot, bad connection or perhaps glitchy RAM...

@@GadgetUK164 i uploaded a video to my channel showing what it's doing ru-vid.comTsvN0FnIZe0

Glad you found them =D I cannot remember where I found them!

Cheers mate =D That's an honour from someone of your skill =D

Thanks =D Glad you got your Megadrive working and pleased I could inspire something positive =D

I'll be working on a video that quickly sums up some recent repairs that I did over the last couple of months and the Mega Drive will be a part of it. Thanks again!

Yes - that's how coninuity test works! It will beep if there's a very low resistance electrical join between the two points you are measuring.

Thanks! yes, that will do the job =D

imagine the magic smoke!

Wow, thanks!

Thanks =D

Hehe, never had that before! I imagine that maybe that particular Genesis had a problem with one of the inputs and its pull ups or something. I have heard of Megadrives having dodgy controller input problems due to a failure inside of the chip that handles the controller ports.

Having a problem with a Sega Genesis 3 what the hell that's really weird

It is very impressive! Especially some of the high speed video stuff in that demo. I've not looked at Megadrive development before, and spent very little time looking at 68K ASM, but the CPU is pretty fast @7.6Mhz, Amiga-ish. The DMA must be better than you think!?!?

Oh i was mistaken, this is Overdrive 2, an 8MB cartridge. Still, no less impressive. Megadrive makes things that you expect to see in games very, very fast and easy, you normally don't even need pervasive line interrupt since there are line and column scroll registers, per pixel. So even games with pretty advanced effects are actually doing pretty benign things from the hardware perspective. Also if you can express computation as selecting tiles that are already pre-drawn, this can pretty much always be done quickly enough. But when you get to individual pixel level, the system tends to fall short easily. Many of the approaches you'd be used to from an Amiga would not quite work. DMA controller will copy 2 bytes per cycle, which is fine, but during this time, CPU is halted.

Not much of a DMA is it if the CPU is halted lol

But I guess that makes sense - the 68K can hardly be allowed to access the RAM whilst DMA is working with it. That's where some kind of split RAM system we be mega useful. eg. a region where the CPU can access whilst DMA takes place into another RAM region etc.

Don’t forget the cool undocumented stuff in the VDP!

LOL!!!

Possibly failed audio opamp or something like that.

GadgetUK164 - Retro Gaming Repairs & Mods any suggestions?

In the UK they are pretty cheap at around £10 to £15 for a MK1. The MK2 seems to sell at a similar price too. But that excludes a PSU, AV cables or joypad.

ok thanks🙂

Haha :o) I knew someone would post that, so I thought I would beat them to it!

Tinha que ter um brazuka aqui falando uma par de bosta né kkkkkk

Well, in the 90s there were many arcade ports for Snes and all of us who had this console grew up happy and content.😊😊😊😊😊

You shouldn't really short connections like that - if you need to, its a sign of a fault somewhere or a bad trace. How did you work out which connections to short?

Both pal models happened after 60hz mod which is cutting one trace but also after switching them on and off so many times. I didn’t care - I buy them faulty then fix them. So they were “faulty” to begin with. It completely revived the other system and its been working normally. I was just messing around tbh