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Hello
I got a sega cd the other day and I just can't format it.
it says that the system has been formatted but it doesn't when I chick to see what data is on the system I get these random symbols and stuff.
when I format it again it says that 236997 or something free space and the same amount is being used.
I removed the battery and still no luck.
Any advice?
It is a old pal mega cd model 1. (Still has a eprom for a bios holder)
Post and search here for extra help:
http://www.sega-16.com/forum/showthr...-repair-thread
Maybe the battery is going out on it? If I couldn't figure it out I would probably try and remove the battery from the board, put in a coin cell holder, and then put the battery back in. If it still doesn't work then get a replacement rechargeable battery and give it a whirl.
I did that.Quote:
Originally Posted by xelement5x
I even left the CD to stand unplugged over night to make sure there was no power at all, but still corrupt issues.
Sometimes it doesn't even let me do a format.
During one of the times you can format, can you save a game immediately afterwards, and then come back to that save spot?
Hmm, have you tried running the system without a battery in there at all? From what I understand all the battery does is trickle power the RAM that holds the saves. Without a battery you should still be able to turn on the system and format the RAM. If you can't then I would assume that the RAM is messed up.Quote:
Originally Posted by PvtHinge
Yes I even tried that. I rsn the machine with out a battery. Still no luck. When ever I play again I get a screen tgat say internal ram not installed, there has been no way to get past there.Quote:
Originally Posted by xelement5x
I have a similar issue with my Sega CD model 1. Rather than start a new forum thread, I thought I would just chime in on here and see if anyone can help me.
I have replaced the battery as I thought this was the issue to start with but I'm still not having any luck. The issue is when I run Sonic CD it tells me when the game boots to "Please Format the Ram" or something to that effect. When I go into the options menu and try to format the ram I get an error with a loud beep. It simply says "Cannot Format" and I can't continue in any way.
In reading about this problem one thread said something about power and how the sega cd can lock the ram out if not enough power is getting to the system. When I bought this system on ebay the guy who sold it to me didn't give me the proper AC Adapters from sega. I have a model 1 genesis attached to this unit so I'm running two ac adapters. One AC Adapter is 9v but I know the mh is lower than the official sega adapter. The other adapter is from a Turbographix 16 which runs about 10v but I'm not sure on the mh rating. I have placed an order for official ac adapters in hoping it can fix this problem as I really don't want to replace the ram chips if it is as simple as a power problem.
My question is would proper AC adapters fix this problem for good?
Or are my ram chips gone and I need to get them replaced?
Has anyone had this problem from using the wrong type AC Adapter..?
I guess I'm looking for words of encouragement here as I've never had this issue even when I owned a sega cd back in the day of release. Obviously the guy who sold it to me didn't know about this issue or played games that didn't need to be saved to ram. Before he sent the system he forgot to get his Rebel Assault disc out of the cd tray, so in winning the auction I got a free copy of Star Wars Rebel Assault.
Mine did format (I was using a real 100% not 3rd part power supply too)Quote:
Originally Posted by qzack
I tried with a different power supply as well no luck.
I read that you need to leave the sega cd to "charge" if it was off for a long time and i only then got the odd has 0 free space of 0 space glitchy-ness .
I replaced the caps and the chip it's self and now it works... replacing the chip is not easy, it took a hell of a long time.
here are some links where you can find a replacement or can just be of use to you.
This chip I used but these are in South Africa like me... really made it hard to fix this. I swear I am the only person who has one here.
http://za.rs-online.com/web/p/sram-m...chips/0391719/
here is a website that has alot of useful info on the sega cd eg: part list
http://console5.com/wiki/SRAM_64Kb:_8K_x_8-bit
I recommend maybe buying a broken sega cd that can't ejected discs or some thing and just switch boards around.
or getting a A offical Sega Mega drive or Sega Genesis power power cable (I know that the sega CD is picky about it's power supply) to power up the beast up.
Maybe you will have more luck than me.
Thank you very much for the reply.
The information you have provided has helped me.
Now I just need to decide what direction I want to go.
Attachment 8681
Attached in a picture of a motherboard from a sega cd model 1. I currently have the problem where I can't format the ram and when I try to do so the unit just beeps and says "cannot format".
I understand from posting here earlier that the ram on the motherboard can be replaced but which chip is it..? Can someone take this image and make a reference mark on it for me identifying which chip is the sega cd internal ram..?
I get an "invalid link" message when I try to click on your attachment.Quote:
Originally Posted by qzack
I quickly tested the attachment when I first posted the message and it worked fine, so it must be a forum error or something.
Here is another image which should do the job.
http://img20.imageshack.us/img20/4789/dsc0439td.jpg
I need to know which IC's are the ram chips or the chips directly responsible for allowing the unit to save games or put saves on it.
In reading this article from console 5, they talk about this layout....
837-8952 IC BD MEGA-CD MAIN BD EXPORT (171-6326B)
IC1: CPU: MC68HC000FN12
IC2: 315-5548
IC3: PCM Sound: 315-5476A
IC4: ROM: MPR-15045B-T
IC5: DRAM: 424270-80
IC6: Battery Backup IC: MB3790
IC7, IC8: VRAM: TC611664Z-80
IC9: HC245
IC10, IC11: SRAM: 65256BLFP-10T
IC12: 74AC86
IC13: CDROM LSI: LC89515
IC14, IC15: SRAM (CD-ROM Decoder): MB8464A-90L
IC16: SRAM (Save Game): MB8464A-10L
IC17: 74AC74
When I look at this list I see more than one chip. I'm wondering if just replacing the IC16 would fix my issue or should I replace all of them while I'm doing just the one.
I know this job is going to be a PITA as I have never tried too or attempted too remove an internal controller chip from a board. I have watched a few youtube videos on this and they make it look easy
with the right equipment. I really don't want to put my entire life savings into getting this unit working.
https://www.dropbox.com/s/ij99nsobuh...0optimized.pdf
According to the above schematic on page 2, the BRAM is reference designator IC10.
This seems a bit odd to me seeing as how IC10, according to your picture, is quite far away from the Battery. I personally would've guessed at IC16 being the BRAM from the looks of your picture. However, I can't really read any of the IC markings from your picture, with the schematic in hand, you should be able to confirm that IC10 is in fact the BRAM.
Edit:
On page 8 of the service manual linked above, it shows that IC10, is located where IC16 is in your picture. We seem to be dealing with two different revisions here...
You should look into get a Hot Air Rework Station. You can get a pretty decent one shipped for under $100, it would make short work of lifting the surface mount SRAM chip.Quote:
Originally Posted by qzack
I would start by just replacing IC16 personally. Incremental troubleshooting is always best...Quote:
Originally Posted by qzack
Thanks for the reply.
As much repair as I do $100 for a rework station may be overkill. :)
I just do this as a hobby and solider basic stuff in college as part of coarse in electronics engineering.
I do however appreciate the advice.
I'm still thinking that this may be more of a voltage issue than one with the actual IC modules because of the fact that I can't format it at all and get an error.
I have a multimeter at home, what would be the points on the board to check for proper voltage..? Part of this problem (formatting the ram) has to do with the voltage regulator not giving enough
so the system locks the ram to battery and makes it so you can't access it. If I were able to access it and format it then discover that my saves are corrupt or won't save, this might
explain to me the modules going bad but this is not the case.
IC6: Battery Backup IC: MB3790 (referenced as IC9 in the schematic I linked earlier)Quote:
Originally Posted by qzack
This IC determines which voltage supply the BRAM operates off of: the internal +5V, or the battery (when the power is off). It has a comparator built-in which automatically switches the BRAM over to the battery supply when the console's internal +5V supply drops below a certain threshold (i.e. when you turn off the system). Important pins to measure on this IC, and they're expected readings are:
Pins 13,14 - Vin - should measure +5V when console is powered up, 0V when powered off
Pin 5 - VBat - should measure around +3V regardless if powered up or not
Pins 3,4 - Vout - should measure a bit under +5V when console is powered up, and a bit under +3V when not powered
A powered state might be hard to achieve with the cover off and what not...
This is the best I can do by simply looking at that schematic, I do have two model 1 Sega CDs at home, I can conduct tests in parallel to yours to help you out over the weekend if you require.
Here is a dropbox link with better pictures of the IC chips.
https://www.dropbox.com/s/e3uuevz5ebet63y/SegaCD-MB.rar
I appreciate the help that you have given me. I plan to open up my model one tonight and start checking voltages.
In looking at the pictures from the drop box download above, check image DSC04807.jpg as it is a nice pic of the model one motherboard.
This board layout is the same as mine I'm pretty sure.
This should give you the right IC numbers as they are clearly seen. Let me know if by some chance you want me to check another IC....
Thank you again for helping me.
Those pictures are of a different revision than your original picture. While most ICs look like they're in the same place, the reference designators are not the same, be weary of that. These new pics on Dropbox do line up with the schematics I provided however, hopefully this is the same revision as your unit.
Yay, thats my picture / Mega CD! :cool:Quote:
Originally Posted by qzack
I hope you don't mind me borrowing it then :)
I appreciate it as I wasn't at home to take pics of my board but it matches perfectly.
No problem! :cool: I always keep looking for my own pictures in case some one would use it for scam or claiming they took the pictures. But since you using it for "fair" use i don't complain. :cool: I hope you can get your Sega CD back together soon. Sadly i can not help since i am not smart enought to be at any help.
heres IC16 forsale http://www.mcmelectronics.com/product/P-MB8464A and I get a dealer price from there so if you want to try I will call and see how much it would be for me to buy for you
Ok. I totally messed up. F$!?ed up is more like it.
I had just ordered a cap kit to start replacing some of the smaller circle (game gear) caps.
When I went to remove C43 it pulled one of the solder pads off the board. Where can I run a jumper wire
to compete the circuit...? The pad is totally gone. I was careful in trying to remove the cap but apparently not
enough. This is on my unit with the ram issue.
On the other unit I have combed the board looking for damage and it's impossible to know where to start. So now
I have two dead sega cds. One that freezes on boot up and the other with a pad I broke off with no access to the ram.
Before I started the cap replacement on the one board I took voltage readings on the IC 16 and they are way low below 3 volts. The board that freezes on boot, I took voltage readings on it and got around 2.2v
always add solder to the pad before removing it, it lowers the melting point of the existing solder. do you have a pic ?
Yes.
It was the Positive Pad (+) on C43 that I messed up. The negative is fine and intact.
https://drive.google.com/file/d/0B_Y...it?usp=sharing
I fixed the damaged pad by "carefully" scraping the board to reveal some copper and soldered the cap. My sega cd behaves no different than it did before the cap replacement on the main board.
I have not replaced the caps on the power board as of yet.
I also left the two 100uf caps on the main cpu board alone as I don't think by replacing them my memory format problem is going to be fixed.
I am glad that my unit has returned to normal function. I did play a few games and it doesn't act any different than it did before. I'm not sure what C43 does but I must of fixed it
or I think I would be experiencing some king of additional problem than just being unable to format the ram at this point.
Hey qzack I responded to one of your threads regarding this issue a while back. Well I have an update. I did a full cap replacement and it didn't fix my ram problem either. I really didn't expect it to though. Then I tried re flowing the ram chip, again that didn't work. Then I used some chipquick and removed the old ram and soldered in a KM6264BLG-10, which I had researched a month or more ago. Fired up the system and was able to format the ram first try. So far it seems to be working great. Unfortunately I can't test the ram further because the system wont read any discs. I replaced the laser in it at the same time but that didn't seem to help in that regard.
There is a guy on ebay selling the ram chips for about US $10 shipped.
EDIT: Oh yeah thanks db electronics I used your information to check for voltage on IC6 to make sure that was working as well.
And for all you "pics or it didn't happen" people.
http://imgur.com/LOI6vj8
Not my best and I haven't cleaned up the flux, but the system is still essentially useless so...
The replaced chip did it format to 125 blocks or larger? if larger I might get one :)Quote:
Originally Posted by Xalphenos
No it wasn't any larger. It is exactly the same as the original. You got me thinking now though. Does anyone know of a larger memory chip that would be compatible?
I was looking for one too :) I was trying to find one that would give me 4096 kbit chip to get the max memory the Sega CD cart can do. but I dont know if the BIOS would read it correctly. I was trying to get an emulator to read more in the internal memory, but to no luck
The BIOS only allots so much memory for the internal Backup RAM. Even if there is any space left in the memory map, I'm not aware of a means to indicate to the BIOS the presence of a larger internal memory.Quote:
Originally Posted by Xalphenos
and that's what I was thinking would happen. Because of the Emulation running the BIOS I was not able increase the memory, it wouldn't work on the hardware. unless there is a custom SCD BIOS that would look for more memory.Quote:
Originally Posted by db Electronics
I appreciate the reply and advice given. I have since gone another route and purchased a model 1 with a good working motherboard. I can now access the ram no problem and played Sonic CD last night with no issues.Quote:
Originally Posted by Xalphenos
ic 16 is the back up ram ic as i had a bad ram chip.
i just used other and saves was fixed i recommend all sega mega cd/sega cd owners replace batterys and caps even if they are ok.
i do ever sega mega cd multi mega or even sega cd or cdx i do the same as stranded
i found what causes bios background no boot animation ic 5 but can be ic 8/ic8 cd-roms not working even the cd-rom drive works on other ic14 ic15
faulty pcm sound ic10 ic11
this is for 837-8952 boards
i have a stack pile of motherboards saved over the year me just having a mega cd repair addiction werid but i like it.
I am becoming the same :DQuote:
Originally Posted by raylyd