SMS, Genesis/MD1, and both Sega/Mega CD variants all use the same power supply. The 10V version of the Neo Geo AES also works with this power supply. The 32X and Genesis/MD2 use power supplies with lower amp ratings and positive voltage on the tip/center. Barring the Neo Geo, I don't have any other Japanese systems, and I have no European systems, so off the top of my head, I can't say if other systems or variants use compatible power supplies.
Could You please tell me exactly lenth for Sega 32x ribbon cables. I have one without it and need to find some replasemants. It seems like 20pins with pitch 0,5mm shood be fine. I have two options 6sm and 10sm to order.
Hi guys,
New member here just starting out with repairs and I'm reaching out to the community for a problem I'm having a lot of trouble finding info for. I couldn't find it here anywhere. If it's here I apologize in advance as well as possibly not knowing the correct terminology.
Long story short, I got a "working" Sega CD model 2 that ended up needing a new laser. The pots on the main board were all out of tune as well.
I replaced the SOH-OT4 laser (w factory laser w original glued pot) and used ohm settings for the main board pots that I found on another forum (with the help of Google translate, and deep scouring of any sources available)
https://picload.org/image/ripiddgr/messung22.jpg.jpg
I used these settings with the board completely removed while using an ohm meter on the pot contacts underneath the board and finely dialed these numbers in exactly.
I consulted the repair manual for this model but it wasn't much help without the special tools required for Sega techs so I had to use a multi-meter set to ohm resistance.
Everything I tried in the system worked fine after I replaced the laser and dialed in these numbers on the pots so I was truly grateful for whomever posted that but I'm wondering, have any of you run across this issue or may be able to confirm these as at least pretty close to stock settings using ohm resistance? It's for the variant of the Sega CD model 2 that has the Samsung SOH-OT4 laser and main board in the pic above.
Thanks for your time! <3
A very simple question from a newb. I'm trying to to take off the heatsink off of a model 1 JP sega mega drive to look at the capacitors underneath. But it's stuck really hard to one of the 7805 regulators. What can I do to loosen the dried paste?
I would try a small flat blade screwdriver (2.4 mm) and work it between voltage regulator and the heatsink, maybe lightly tap the top of the handle of the screwdriver with something like another small screwdriver straight down in between the heatsnik voltage reg. if it gave me a hard time. Could also try a small amount of isopropyl alcohol one use to treat cuts in the skin to re-hydrate thermal compound. You will need to replace this old thermal compound with new when you go to put all back together.Quote:
Originally Posted by toadhall
Thank you! That worked. Started by cleaning the excess paste from the edges of the 7805 with isopropyl alcohol, then I prodded gently with a small flat blade screwdriver. The heatsink eventually came off. I'll be sure to remember to put new paste when I put it together. Have already cleaned the old paste off from both 7805s and the heatsink.Quote:
Originally Posted by EyeDeeNo76
Hi all, I am new here (took me a while to be able to post) and I own a small but awesome game console collection. My highlight is without doubt my Sega Megadrive + Sega CD (mk1) + Sega 32X combo that I've been playing on for years. At some point it just stopped working, the machine boots up but gets stuck at the BIOS screen (as is not uncommon) and refuses to do anything. Once in a while the lights on the machine light up, but usually they dont. The CD tray does open with some persuasion, but that's about it!
This has nothing to do with the Megadrive or the CD inserted. I've also replaced the power supply. A friend of mine has already recapped and replaced fuses on the Mega CD but this didnt help at all. I need some pointers to be able to sort this out. Is there anyone here who actually managed to repair a mark 1 Sega CD with this issue?
Since you all like pictures I have included a picture of someone's Sega CD with a similar issue. It was either that or a picture of my cat, sorry.
Attachment 13327
Please help. I really want to get this machine fixed up.
So just recently, I noticed that my Model 1 Mega Drive has some distortion when playing music. It's more noticeable when playing Sonic 3's Ice Cap as an example.
I've checked most of the capacitors and from what I've seen(Having trouble removing the heat plate), I can't find any signs of leaks or the cap tops elevated. Though underneath parts of the board is some kind of yellowish stain of sorts with no signs of corrosion or damage(Flux maybe?). I've tried 2 PSUs as well, the Aussie PSU I bought recently and the original Japanese one with Step Down Converter and the audio distortion is still present.
Reading the post about the Mega Drive models, apparently the VA2 I have:That said, is the distortion that I'm hearing a result of owning a VA2 MD or could it be something else? If it is the former, would it be worth installing a Mega Amp or would that be overkill?Quote:
will be clear with very high bass and is prone to distortion with loud games due to excessive gain on the preamp.
I have a Sega Genesis Model 1 VA2 HDG Non-TMSS. It's an original launch console from 1989 and i have a question. Is it normal for VA2's to have low sound in RF Output but loud sound on AV? Also Sometimes my VA2 freezes randomly. Is it proably time for a recap or a cartridge cleaning.
Here is my board: Attachment 13390
Chaos Fusion - There is not always signs capacitors are bad they can dry inside and appear normal.
mariostar82 - With an Coaxial Radio Frequency Switch everything is mashed together the video picture and sound than the television needs to unpack this information and transmission of microwave signals/RF energy from console to the television stuff gets lost in this process and also depends on how good the television is at doing so.
Always try the easy stuff first. I would clean the cartridge slot and the games.
Using attachments on vBulletin can be tricky I suggest imgur or Postimages.
Always try the easy stuff first. I would clean the cartridge slot and the games.
I appeared to clean my games and it solved the problem, but plus, I'm not good with recapping. I accidentally destroyed another Model 1 VA2 by doing so that had a 39S29259 serial and the really early 800- number. My 39S6 console on the other hand is the one with the usual 1-800. So is the 800- the really early number? Because i see it all the time on SMS 1 consoles.
Well dammit.
Assuming that the problem is the Capacitors, Would I need to replace all the capacitors in regards to sound(Don't know which ones are potentially faulty so might as well just replace all of them) or all of the caps on the motherboard in general?
Edit: To avoid double posting, Reading this post about fixing the preAmp for earlier Model 1s, http://www.sega-16.com/forum/showthr...l=1#post601668
and I'm a bit confused regarding what you are meant to do. Since this is under the Motherboard, am I supposed to solder some new capacitors + Resistors underneath the board to those bits and cut the traces or are those points meant to be connected to Caps on the topside of the MB? This is mainly for future reference and not a priority.
I have a model 1 genesis revision VA6 that isn't outputting sound or video. On one occasion while fiddling with the AV cord I briefly saw the TMS screen, but I've been unable to reproduce this. I'm sure the power supply is good as I've tested it with a multimeter. I'm almost certain the cartridge slot is clean as it is both visually free from blemish and has been cleaned repeatedly with alcohol. I haven't used sandpaper on it yet which I've seen some people recommend, but I really don't think it's dirty. Using an rf connector the screen on the tv changes slightly when the console is turned on, but does not produce any picture. When listening to sound through the stereo port in the front there's a white noise buzz when the console is turned on, but no real audio. None of the capacitors are visually obviously bad, but I've read that a capacitor can be bad without showing it. There's no thermal paste connecting the heat sink to the voltage regulators, but that doesn't seem like it would cause this problem to me. Some of the solder points for the voltage regulators were a little thin so I reflowed them, but this didn't fix anything. Solder joints for the av jack and power jack seem good. No obvious scratches or damage to the board.
Any idea what is wrong with it or even how to proceed in troubleshooting? VA6 is the model I want and I got a really good price on this thing so if possible I'd really like to fix it, plus I'd like to learn more about trouble shooting and repairing pcbs in general.
Maybe the 7805 regulators are going bad?
I'd like to think it was just a cold joint somewhere, but it's hard to say without being able to see the actual unit for myself.
From my understanding, the Japanese Sega CD RAM cart will work fine in a US Genesis.... you just need some kind of passthrough (or to physically alter either your Genesis's port or the cart itself) to physically fit.
Are the insides of the cart the same as well? Would I just be able to buy some cheap Genesis game (Some places sell the Menacer carts for under $1) and put the Japanese RAM cart's PCB in the US game's shell?
Is there a way to test for the regulators going bad or for a cold solder joint with a multimeter or the like? Maybe using the continuity function or something?
Nevermind on the voltage regulator test, found an article on how to do that.
I think it might be the CXA1145 that might be going bad. Did you try checking the chip?Quote:
Originally Posted by Kashan
I haven't checked it, I'm not sure how to actually do that. Any pointers? Do I need a particular tool other than a multimeter for it?Quote:
Originally Posted by mariostar82
Both voltage regulators seem to be taking in about 11v and outputting about 5v which as far as I can tell means they're working correctly
Would the cxa1145 chip going bad also explain the lack of sound? As far as I can tell the cxa1145 chip only governs graphical elements, but I'm not familiar enough with electronics to know whether it could also cause the lack of sound
Actually on a VA6 Model I, the CXA1145P also serves as a buffer for the mono out. If the CXA1145 is malfunctioning (which is very rare, mind you, as they're generally pretty reliable chips but any given chip can fail on any computerized device given enough time) then it could be corrupting the mono audio. But I don't think it will affect Stereo audio through the headphone jack, as mono is tapped right before the CXA1034 headphone amplifier and run through an LM358 dual op-amp, before being sent to the BUFFER IN pin on the CXA1145 - unless it's a particularly nasty fault that's bringing the rest of the circuit down.
Alright so assuming it's not the cxa1145 that leaves what? Cold solder joint or bad capacitor?
Hi, new here, sorry to interrupt the no video problem, but quick question: can I use the conversion cable from the 32x to get video out of a genesis model 1? (I have the model 2 to 1 converter and a model 2 av cable.)
It's a shame eBay is a bit of a crapshoot getting replacement chips. If genuine CXA1145Ps (and Ms for that matter) could be purchased reliably for them, it'd be worth a shot to eliminate the CXA1145 as a suspect. I'm still leaning toward a cold/cracked joint someplace (and the fact that you once got it to display correctly for a brief period of time may also suggest that), but then I also used to think the KA2195D wasn't so bad... :P (to my defense that was before I realized my TV settings were to blame...)
Is it possible this is a grounding issue? The only part of the board that's visually damaged is the plating along the back edge of the motherboard which seems to have had some corrosion and seems to be involved with the pcb ground. I've checked and there's continuity between that plating and the ground on the a/c plug.
The crystal oscillator is also oddly elevated in the front, as though they didn't have it fully seated when they decided to solder it, but the solder joints on it look good.
There's a hole beneath the IC1 chip that looks like it could have a part soldered in and where there's a chip in the pcb, but from what I can see on various schematics the path to the left of this hole (which leads to pin 6 of the mc68000) is working as intended and the path to the right where the chip is located (Leading to C94) is a dead end and doesn't exists on any schematics. I found some discussion that this area was a misprint in the pcb that was corrected after the fact with the soldered on extra parts.
Sorry for another post, but this time it's an actual problem. I received a Genesis Model 1 recently and it works fine, but when I cleaned it I went over the expansion bay "Piano Contacts" with a q-tip dipped in rubbing alcohol. It looks a lot cleaner but now it's not working with both sega cds I have. I have a model 2 genesis which when attached both sega cds work. Anyone have an idea on how to fix the model 1's contacts?
Edit: nevermind, plugged it into a different outlet, suddenly feels like working.:D
Edit 2: Ok, for some reason it only works if I have a 32x attached. I don't even know anymore...:|
I think so. It's meant to send RGB to the 32x for processing, but I don't see why it wouldn't work.Quote:
Originally Posted by shewdew
You'll still naturally need the headphone jack to get stereo.
I tested it, and it works, but no mono audio. Whatever, I'll just get a new model 1 av cord for like $7.
Sorry for another post, but this time it's an actual problem. I received a Genesis Model 1 recently and it works fine, but when I cleaned it I went over the expansion bay "Piano Contacts" with a q-tip dipped in rubbing alcohol. It looks a lot cleaner but now it's not working with both sega cds I have. I have a model 2 genesis which when attached both sega cds work. Anyone have an idea on how to fix the model 1's contacts?
Edit: nevermind, plugged it into a different outlet, suddenly feels like working.:D
Edit 2: Ok, for some reason it only works if I have a 32x attached. I don't even know anymore...:|
Alright so now the Sega cd works with the model 1 genesis, but now the issue is the cd wont boot unless there's something in the cartridge slot. such as for example, a game genie or 32x. if i turn it off with the cd tray open and place a game (such as sonic 1) in the slot, the liscence screen comes up, but the genesis detects the cd and closes the tray! My only guess is the genesis doesnt check the expansion bay unless there is something in the cartridge slot. Help?
Are you using a mono model 2 av cord? on the model 2, mono audio is available as a separate pin.Quote:
Originally Posted by shewdew
stereo cables, or cables that combine stereo, would be using pins that don't exist on a model 1.
No, I'm using a stereo one. That's probably the issue.
Anyone? I can leave the game genie in but i would like to get this fixed!
EDIT: I'll just pick up another model 1, they're not that expensive, and it's an issue that would cost more than the genesis itself to fix with the connector.
I think I'm giving up on fixing this thing. Whatever is going on with it is beyond my skill
One short question, I haven't been able to find the answer :
Do all Genesis Model 2s have TMSS, or does a non-TMSS unit exists ? As for the Model 3, I would assume that all of them have TMSS, correct?
Thank you
All Genesis 2s and 3s have TMSS, only pre-VA5 Model 1s lack it. read here for more information: http://www.sega-16.com/forum/showthr...-from-bad-onesQuote:
Originally Posted by GameX
About to change the Caps on my Mega Drive and in regards to the heatsink that I removed. Does it matter what type of thermal paste I use as long as it doesn't have silver in it? I got some stuff from Jaycar: Nano Diamond thermal Compound for reference.
Pardon if this is common sense for others.
Bah, I'm a dumbass. Never mind
Hey guys I am having trouble with my genesis emulator. I am using the emulator called Gens. When I make a save state it saves it as the filetype "file" and these files cannot be loaded. In contrast the quicksaves do work and they have the file type GS(and a number). Does anyone know how I can load the save files I made?
Okay so I actually found the solution to this problem by searching this forum for gens emulator save state. Props to user The Jackal for the solution; Gens doesn't recognise its own save file format so when you load a state you have to change it from "save files" to "all files."