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PostPosted: March 8th, 2013, 11:11 pm 
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Hello everyone,

It's been quite some time, but my first two PC98 computers finally arrived from Japan yesterday and I've delved into learning about them immediately. I decided to get:

1) A PC98DO, with the DO keyboard, mainly for playing 5"inch Floppy Disks and for playing PC88 games as well and...
2) A PC9821 Ce2, for playing anything released on 3.5" inch Floppy Disks and CD-Roms.

I figure together, the two computers would allow me to play most of the PC98 library that I may come across perhaps. : )

The good news is! They turned on! And they read many of my games! :D

The bad news is, specifically on the Ce2, the CD-Rom appears to be broken. :?

Upon powering the Ce2 originally, I pressed what would be (I believe...) the eject disc/open cd tray button, and the button instead of doing something, went inside and got stuck....

So, I decided to take the case off and the front case as well and I noticed that right where the front case would align, the button would be hitting a small black/grey peg that is contained inside a small square-shaped housing on the CD drive. So I turned the computer on again, this time without the front case and hit that little black button and.....!!

The button went further in.... this time becoming completely stuck within the square housing it seemed and it was not showing any signs of coming back out....

So...

I took out all the screws and floppy disk drives and harddrive in order to eventually make my way deep into the case where I could finally pull out the CD-Drive, and then I took the drive apart so I could see what was inside and possibly causing an issue.

I noticed that this black button fell right out, and that was mainly due to it not being connected to anything that I could see inside that little square housing. Now, I do see that there appears to be some kind of copper disc inside the square housing, and the drive does power on with a orange LED light when the computer is first powered on, so that seems to indicate to me that this drive might be salvageable still as long as I can repair this button somehow.

Would anyone here be knowledgeable of how that is done perhaps or what I might try? If it doesn't seem like an easy enough fix, are there any CD-Rom drives that are easily obtainable from something like eBay that should work with the PC9821 Ce2?

I have pictures below to better showcase the issues I've run into. I've tried to show this visually as best as I can:

Image
Image
Image

Top of Case - Model Information
Back of Case - Port/Connector Information

Image
Image
Image

Some questions I also had about harddrives. Can pretty much any IDE harddrive work? The one that came with the Ce2 inside is this one:
Harddrive Model Information

I guess once I get the CD-Rom drive issue resolved, the next thing I would want to try learning about is how to install an operating system, and Dos perhaps... but I'll look for some beginner threads for that information.

I did have one question though, I played a bit of Brandish 3 last night on disk on the Ce2 and saw that it could handle the regular beeps sound, is this similar to PSG sound? And two types of FM sound, that I am familiar with having used an MSX computer before with FM sound built in. I guess my question is, would there be anyway to enable FM sound on my PC98DO via a C-Bus sound card of some kind?

Thanks very much for all of your help as always, and I look forward to getting into this hobby full steam ahead! : )

-Thomas

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PostPosted: March 9th, 2013, 3:13 am 
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Regarding the CD-ROM, it looks like the standard button-switch you'll find on virtually all CD drives. I figure if you can pick up a couple of old PC/Mac CD drives you could get an electronics person to desolder a switch off the old one and solder it onto your one. Get him to check which pins get switched when you press the switch and match with your one. Old drives are common and just about worthless - any shop doing PC repairs should have some lying around. Alternatively, is it an IDE ROM? If so you could set the master/slave jumper correctly and try an old one ( suggest testing whether it reads correctly on an old PC first so you aren't blundering too much about in the dark ). Just take off the front plate on the replacement drive.


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PostPosted: March 9th, 2013, 5:26 am 
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Hello Thomas,

the MESS developer team is still looking for a real NEC PC-98DO dump.
Are you willing to dump the needed ROMs? This will be great.
Just run the file "DUMP.EXE" on your NEC PC-98DO.
The DUMP.EXE read and write following ROM (files) on floppy disk:

2DDIF.ROM
2HDIF.ROM
IPL.ROM
SOUND.ROM

Not sure you are able to transfer files from PC to PC-98DO and vice versa.

The DL package contains:

Dump.exe (Dump tool)
Dump.png (Screenshot*)
Dump System.fdi (bootable Floppy Disk image with DUMP.EXE)

Download

Thanks in advance. : )

Anna

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PostPosted: March 10th, 2013, 5:00 am 
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Hi again Peter,

You've always been very helpful at this forum. Thanks for the advice again on my current issue. I think I will look for a few older replacement CD-Rom drive and perhaps try to see if I can get them working first and see if they'll be a viable replacement option, or I can do as you suggested and try to take a part from an existing unit and see if I can have a savvy electronics guy take a look at it. Never really thought about it before that a computer repair shop might have the expertise to repair something old like this, but you may be right about that!

I guess worse comes to worse, a friend of mine and I are planning on doing a 30th Anniversary MSX exhibit this April at the first Vintage Computer Fair Festival in Atlanta, so if I don't have it repaired in working order by then, I can always bring the drive with me to the fair. : )

----

Hi Anna,

Sure, I don't mind making a dump of the roms. I've not done something like this before, but I'm sure I can figure it out sometime. Is there an email or something you would prefer I send the files to?

-Thomas

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PostPosted: March 10th, 2013, 10:27 am 
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Hello Thomas,

a private message sent, check your inbox. : )
If you have any questions don't hesitate to contact me.

Anna

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PostPosted: March 14th, 2013, 5:50 pm 
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Hi Anna,

I haven't forgotten about your request to dump the needed from files from my PC-98DO, only I've hit a bit of a snag unfortunately. The only keyboard that I have on hand that is compatible with PC-98 computers is the very keyboard that originally came with the PC-98DO. I was planning on using this keyboard interchangeably with the PC9821 Ce2. However it appears upon further testing that many of my keys do not work currently and after having read some keyboard repair tutorials, this may take me some time to figure it out. lol I actually do not have the correct keys for calling the A: drive and running the executable file to launch the dump program! Worst comes to worse, I could at least see if there is an autoexec bat that could be written and simply saved onto the disk that you provided that would virtually to the same thing, but I'd really prefer to fix the keyboard if it is possible...

I mentioned this before, but I'll mention it again here. I'm a total beginner when it comes to working with electronics. I've repaired some things here and there, but I've also broken things too, such as the ribbon cable on my PS2 when trying to fix the CD-Rom once... Or ruining the traces on several cheap PSX controllers in order to try to make a custom Pop'N Music controller, only because the choice in wire I had selected tended was a poor choice and was much too stiff to work with. I think given my track record, I'm probably about 30/70 in success rate to utter project failure... So I'm trying to take things really slow especially with some of these more precious items that would be fairly difficult to replace. After reading the most current Keyboard repair tutorial, it has left me with a... "Whaaaat?", although I think I still understand the basic concepts, that bad keys tend to be aligned vertically and I need to somehow determine where the bad trace is and repair it with some kind of Trace Repair Pen. I think it's the in-between steps of figuring out just which traces are bad that has gotten me confused...

At any rate, it's no substitute for being able to hook it up to a virtual keyboard to test the PC-98DO keyboard, but I'm fairly sure that I've isolated the bad keys to the following diagram, although some keys such as function keys or others may not be working simply because they have no real function assigned when first starting up the PC98DO in 98 Mode:

LEGEND: RED = Confirmed BAD Key, BLUE = Not sure if BAD, or not assigned a Function on Startup Screen. Uncolored means that the key is working correctly as far as I can tell.

Image

In other news, I was able to finally repair my Open Tray button on the original PC9821 Ce2 CD-Rom Drive. However, I'm not sure it's working. I can boot up the computer, it beeps, counts the amount of available ram, and then a simultaneous orange LED light blinks right near the Green Power button and the Orange LCD light on the CD-Rom drive at the same time. I put in my CD-Rom, such as Xanadu Revival or Brandish Renewal for example and close the tray. I don't hear anything at first, and then I hear a faint noise indicating that I believe the CD is being read or attempting be read and nothing happens on the screen. The computer tells me that Dos 6.2 apparently is installed and is waiting for a command from me, of course with my keyboard troubles above, that is a bit limited to be able to enter commands at this point. lol

I've also tried resetting the computer with the Reset switch while the CD-Rom game is inside the tray and nothing happens still. There are also no floppies in the two 3.5" Floppy Disk Drives. Am I doing something wrong, or does a command need to be run first to allow a CD-Rom to play? I would think than an Autoexec.bat file would be on the CD somewhere and it would work once it is initalized... or maybe my CD-Rom drive just doesn't work.

What should the normal experience be for this when using real PC9821 hardware with CD-Rom support?

Thanks very much for any advice you all can give me. : )

-Thomas

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PostPosted: March 15th, 2013, 5:32 am 
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SkyeWelse wrote:
In other news, I was able to finally repair my Open Tray button on the original PC9821 Ce2 CD-Rom Drive. However, I'm not sure it's working. I can boot up the computer, it beeps, counts the amount of available ram, and then a simultaneous orange LED light blinks right near the Green Power button and the Orange LCD light on the CD-Rom drive at the same time. I put in my CD-Rom, such as Xanadu Revival or Brandish Renewal for example and close the tray. I don't hear anything at first, and then I hear a faint noise indicating that I believe the CD is being read or attempting be read and nothing happens on the screen. The computer tells me that Dos 6.2 apparently is installed and is waiting for a command from me, of course with my keyboard troubles above, that is a bit limited to be able to enter commands at this point. lol

I've also tried resetting the computer with the Reset switch while the CD-Rom game is inside the tray and nothing happens still. There are also no floppies in the two 3.5" Floppy Disk Drives. Am I doing something wrong, or does a command need to be run first to allow a CD-Rom to play? I would think than an Autoexec.bat file would be on the CD somewhere and it would work once it is initalized... or maybe my CD-Rom drive just doesn't work.


To get a CD drive to be accessible under MS-DOS you have to load drivers in the CONFIG.SYS and AUTOEXEC.BAT. I do not know what these are on a PC-98, but it will be similar to a PC. You can search: here is one helpful page I found:

http://www.computerhope.com/cdromd.htm

From what you say I can see nothing so far to tell me the drive is not working. The machine is unlikely to autoboot the CD - older PCs of that time did not boot CDs either.


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PostPosted: March 15th, 2013, 3:03 pm 
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Hello Thomas,

I think you donĀ“t need the keyboard or to type something on the keyboard for this case.
Just use my image (Dump System.fdi) which is bootable. The autoexec.bat will run the dump.exe and save the dumped files on the disk automatically.

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PostPosted: March 15th, 2013, 3:28 pm 
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You can try with some of these


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PostPosted: March 17th, 2013, 8:06 pm 
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Hi Wushu and Peter, thanks for the links and the drivers. I'll have to see if I can write a . FDI disk and try some of these settings and the drivers to see if one initializes my CD-Rom drive. It'll just be a trial and error type thing until I get the write combination. I also found a pre-existing CD-Rom Boot Disc for Neko Project II as an .FDI file, only I'm not sure which program will allow for me to copy this disk image to a 3.5" floppy disk using Windows 7. I've used a program called DiskManager before for writing MSX games and it's been great, only with this it does not seem to understand the format.

And this there is another complication Anna, in that currently in order for me to run that Dump program that should be a self-contained program with an auto-exec bat and everything I would need, I not only need a program above that can write FDI files, but I also have no current method of writing to 5.25" Floppy Disks. The BIOS on my motherboard P5QSE only allows a choice for Disabled, 3.5" Double-Density (720K) and 3.5" High Density. When connecting my internal 5.25" Floppy Disk Drive to my PC, it definitely sees the drive and attempts to read from it, but it thinks it is a 3.5" drive and won't read the contents.

So how do you all write to 5.25" disks these days? Is there something I'm missing? I've seen products like http://www.kryoflux.com/ available, as a means to offer a Floppy Disk Controller that will support some of these drives on newer PCs (Mine isn't that new... maybe 5-6 years old?) but it's just a lot of money to throw at something that may work out for what I want to do or may not. If I'm to spend that kind of money on something like a Kyroflux, maybe I should probably just go for an HxC2000 instead and just load diskfiles directly... if it works that is. Seems like it works for PC88 and the format of .FDI at least. Not sure if it would work with PC98 disk files for sure though.

What would you all suggest?

Edit: I had one additional question regarding FM Sound. From what I've experienced so far, I'm not entirely sure that the PC98DO comes with onboard FM Sound, but I do see that there are CBus FM Sound Boards that can be installed into PC9801 series computers. Could anyone tell me if such a board would likely enable FM sound on a PC98DO?

Thanks again everyone,

-Thomas

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PostPosted: March 21st, 2013, 9:44 pm 
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I've got another question that I hope I can ask here as well. Any help you can provide is much appreciated.

I may have mentioned this before, but I have a dual external 5.25" FDD drive that had a bit of an odd port on the end of it, that I just found out today is called a 50 pin Centronics Port. Apparently this is the same type of connector that is found on some FDD drive interface expansion cards for PC-98 systems, and better yet, I think I have found a model now that will be supported by my PC9821 Ce2 that should connect to the Dual FDD drive I have provided I can find a 50 pin male to 50 pin Male Centronics connector cable.

The Expansion card I found is the FDD-1MZ and this kit seems to come with many other cables I would need to somehow connect everything internally to the PC98 Ce2.

Image

So if I were to get this expansion board, what would be the general process for how I would hook this up? I see on the board there appear to be two IDE connectors on one side for the FELLOW / MATE and a separate set for the MULTI, which I would likely be using since the PC98 Ce2 is a MULTI I believe. So would I end up getting a FDD IDE Ribbon cable that is a chain and hook this up so that it connects to the 3.5" inch Floppy Drives as Secondary drives (slaves) and then the other IDE end would go straight into the motherboard? That's what it looks like I would need to do, and then something with the yellow cables too I suppose...

Am I thinking about this logically here or am I wrong in my train of thought on this?

Thanks very much for your time as always.

-Thomas

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PostPosted: March 23rd, 2013, 6:30 am 
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Interesting card; looks like it's a really really fancy breakout panel for the internal floppy bus.

Have you opened up the dead keyboard yet? From the sound of it, the membrane is disconnected or damaged.


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PostPosted: March 24th, 2013, 4:00 am 
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Papa_November: Thanks for your reply. I have not taken the keyboard apart just yet, but I have bought a product called CaiKote 44 which is used to repair membrane buttons, keyboard buttons and other silver & carbon based surfaces, or so it says on the package. It seemed like a decent enough product to try, only I had read that with this product at least, folks have had the best results when curing it with a hot lightbulb or some variant of for about a day to ensure that it doesn't flake off and cause a short somewhere. Just been researching the best methods first before really deciding to open it up and apply this since I've never done anything like this before. Not sure I quite have a setup for curing an open keyboard and buttons with a lightbulb either... so that's the other part. I wonder if hair dryer on a low setting would do the trick...

Yep! This board definitely looks like a good possibility for my Ce2 Multi to have access to both the internal 3.5" drives and possibly a external dual 5.25" drive, only I'm just not real sure how I would go about hooking all of this up if I were to get one of these boards. Any ideas of how exactly I would hook up these drives? I was thinking I might need to have IDE floppy cables (a chain type that has room for one primary and one secodary drive per cable), one from each port on the board (where it says MULTI) and run these to both the internal 3.5" drives and then on to the motherboard. Does this sound about right to you?

Thanks again!

-Thomas

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PostPosted: March 27th, 2013, 10:58 pm 
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Papa November:

I've taken my keyboard apart and found out to my surprise that the actual connections being made seem to be from tiny little NEC connector switches that make contact with the circuit board beneath. Doesn't seem like a membrane sheet between the two that I could just easily disassemble.

Image
Image
*Each one of these switches seems to work like this from what I can tell:

KEYCAP >> clip to plastic switch >>> Left contact point A, a Spring in the middle, and Right contact point B.


Back of PC98DO Keyboard Circuit Board (Large Picture)

The Good: I was able to test most of my keys without the caps on. Sometimes wiggling them so that both contact points A and a B touch to the circuit board contacts below, or a combination of hitting it repeatedly or holding it down long enough or tight enough resulted in the display of the character on the screen. That's the excellent part. The keyboard isn't dead, only perhaps the contacts are weak or have dust in between.

The Bad: I took what was left of an compressed air can I had and went to town on seeing if I could blow out some dust from the keyboard switches, but it's just so difficult to get to what lies beneath and it didn't seem to help much. I honestly have no idea how I would really be able to clean the contacts or apply new conductive material such as that CaiKote 44 to the contact points since each key's switch is basically soldered to the circuit board beneath. Has anyone ever worked with switches like this and are there method of opening these little switches outside of de-soldering each one from the board and hoping it gives me a better view?

The Ugly: Let's say I had to just throw my hands up and give up on this, at the very least, my PC98DO keyboard's special key, the Graph Key allows for me to hold it while booting the system to allow selection between different PC88 emulation modes, V1S, V1H and V2. If I were to buy another keyboard for these PC98 machines (Recommendations would be wonderful too if there are some cheaper, easier to work with keyboards out there!) is there any danger of taking one keyboard out of the PC while the PC is powered on and plugging another one in? Are these devices hot swappable?

Thanks for looking at this everyone.

-Thomas

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PostPosted: March 28th, 2013, 4:28 am 
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Gosh, it is ages since I pulled keyboards apart!

I think the problem is this. On the bottom under-surface of the cream/white sprung thingy in each key is a coating of conductive material. When you press the key, this closes the electrical connection across two or more solder tracks or points on the board underneath. The problem is that this coating wears off with use. You can buy this stuff in the US of A I believe, so if you can get the surrounding black part ( marked NEC ) out you might be able to do something - it looks like it is just clipped in, or get the big black plate holding the keys off the underlying board ( not sure how held on ), you might be able to fix. BE CAREFUL OF SPRINGS! At your own risk. :wink:

Good luck getting the big keytips ( space, enter ) back on LOL. :wink:

PS. Don't force anything, or it will be achey-breaky heart time.


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