PC-9821 Error Beeps

[Tw3ek]

Hello everyone!

I have a PC-9821Ce2 that I finally finished cleaning up (thing looked like it had been buried in a landfill) and got it all hooked up. The machine powers on, but just emits a long solid beep. I know in certain other machines, this indicates a bad mainboard, but I was wondering if anyone knew if it meant the same/something else on the PC-98? Thanks!

[98digger]

The error your machine may be having is a "MICON ERROR".

https://www.youtube.com/watch?v=yu7pf0njB_8

From what I've read, it generally means a hardware error. Try unplugging any expansion peripherals from the computer and rebooting. If removing the peripherals does not work, then the main-board is likely fried.

[RobIvy64]

My Cs2 does this when no HDD is connected.

[SkyeWelse]

Hi Tw3ek,

I also have a Ce2 and as RobIvy64 said, when I have no hard drive connected it and the system is trying to boot from the HDD, it could generate a high pitched beep, but usually for only a few seconds. The only time I ever had an issue where the beep was constant and I received a no system files error was when my front-left IDE BUS board became loose from the connector to the main motherboard. Since my plan is to replace all the capacitors in the computer I have most of the screws loose and tugging on the hard drive power cable must have accidentally dislodged that smaller board. Once I turned that off and pushed that forward more to seat it properly (you may check the ram board too and see if that is seated properly as well since it also plugs into a similar style connector) that beep went away.

Edit: This could also perhaps be related to an I/O Error as well. I had one these errors last night and after the computer attempted to read from the FDD with a few flickering access check lights and no actual reading/spinning noises, it came back with "I/O Error" in the top left corner and a constant Beep sound.

Good luck!

-Thomas

[Tw3ek]

Thanks Thomas.

No errors show up on screen, just a blank screen and one long beep. I'm pretty sure I should just take a sledgehammer to this thing

[SkyeWelse]

Tw3ek - Definitely don't do that! I'm sure there's still possibly a way to get it to work with a bit more research, but if you have given up, please send me a private message or an email before you decide to get rid of it. I've been having some issues with my Ce2 getting the CD-Rom to work and I just recently fried one of my floppy drives in an attempt to try and dump something from the PC98DO, so if you were going to get rid of it, I'd probably want to work out something with you at least for parts perhaps. I've been finding that it's a bit difficult to find compatible parts. I live in Georgia, United States btw.

Now are you sure you have this hooked up to a proper monitor that can support a 24 KhZ signal? I noticed that on some widescreen Dell monitors I did not get any display results, while some 4:3 resolution dell monitors did display a picture. Perhaps have you tried different monitors to see if perhaps it displays an error message on one of them? Then you might be able to diagnose the problem better.

-Thomas

[Tw3ek]

Haha, I would never actually smash it. Hardware is not my forte however, as it makes me quite grumpy. More of a software side of things person.

I have hooked it to a trisync monitor set to 24KhZ with no effect. I do notice that the access light on the IDE to CF module I have set up does not appear to flash, indicating to me the issue is probably in that area.

[SkyeWelse]

Well that's good to hear then! Because you never know and even if the computer is pretty messed up, there are bound to be parts that can be still used. 

If you don't mind, lets start from the beginning regarding your tests so far. You've mentioned that you've cleaned it, that it's generating a constant beep and that it hasn't displayed anything on the monitor as of yet, but that it seems to possibly be taking issue with the IDE to CF Module.

Have you tried writing a floppy disk with Dos 6.2 on it yet and seeing if the Ce2 will read from the disk? In my case, the original owner had set something within the Bios of the Ce2 to make the computer always try and boot from the HDD first if it found one and since my HDD currently does not work, I currently have to unplug the HDD even if I have a valid Dos disk inserted or the system will freeze when it cannot read the HDD. Fortunately, Kobushi just mentioned a solution to this problem in my other thread. I've yet to try it but I have no doubts that at least one of the restoration methods will work.

This is an excellent guide I've found for writing 1.25 disk images to 3.5" floppy disks and for the most part it has worked like a charm so far:

http://www.assemblergames.com/forums/showthread.php?42533-Writing-and-reading-PC9801-disk-images-for-real-machines

Next, have you tried holding the HELP key down when powering on or resetting the computer to try and access the Bios?

Also if any CBus cards are installed, go ahead and remove those. One of my original CBus cards was causing an issue originally after installing it as it had a conflict with another CBUS card that was already in the system for allowing SCSI interfaces to be hooked up to it.

Lastly, you might try some keyboard commands when booting the PC.

http://www.amy.hi-ho.ne.jp/nakajima-jr/com/appendix/uracom.htm (In Google Translated English Below)

Command * 1    Compatible models    Effect
RESET + [STOP]    All models    I will start with no memory check.
RESET + [TAB]    With HDD (connection) machine    Display the OS selection menu.
RESET + [ESC]    With HDD (connection) machine    Display the OS selection menu.
RESET + [COPY]    RAM drive loading machine    Booted from the RAM drive. (Auto mode)
RESET + [SHIFT] + [STOP] + [CTRL]    PC-9801VX later    I recorded in the FD a memory dump. * 2
RESET + [CTRL] + [CAPS] + [Kana] + [GRPH]    PC-9801RA, RX later    CPU name, operating frequency, screen resolution display. * 3
RESET + [CTRL] + [SHIFT]    Only NOTE machine    I want to initialize the memory SW of the body.
RESET + [GRPH] + [SHIFT]    PC-9801DA, DS, DX or later    I want to initialize the memory SW of the body.
RESET + [HELP]    PC-9801DA, DS, DX or later    Display the setup menu.
RESET + [HELP] + [RETURN]    CPU machine retrofit of some 4 *    Display the setup menu.
RESET + [GRPH] + [1]    A MATE and later    The 24kH view the display.
RESET + [GRPH] + [2]    A MATE and later    The 31kH view the display.
RESET + [HELP] + [ESC] + [1]    PC-9821 and later    Display the BIOS revision of the body.
RESET + [HELP] + [ESC] + [5]    PC-9821 or later    The start sending memory refresh signal to the C bus.
RESET + [HELP] + [ESC] + [6]    PC-9821 or later    The stop sending the memory refresh signal to the C bus.
RESET + [HELP] + [ESC] + [8]    PC-9821 or later    View the BIOS update menu of the body.
RESET + [HELP] + [ESC] + [9]    PnP-compatible devices    I want to initialize the PnP BIOS.

* (PC-9821Xa / W, Xv / W, Vxxx, etc.) models no 1 RESET SW, Please replace the POWER SW.

* Press the 2 [COPY], and then recorded in the FD a memory dump from being 1.2MB FORMAT forcibly.

* There may not be displayed correctly when being replaced with a standard 3 CPU.

* 4 PC-9821 Xa / W, in Xv / W, etc. VRM socket mounting machines, body retrofit to K6 series, such as the AMD CPU is intended for.

You might try the commands pertaining to the 24hHZ and 31 hHZ modes.

Hope this helps!

-Thomas

[caius]

I have the same issue with my PC-9821AP2/U8W : noithing on screen and a constant beep.Before doing this, the computer worked fine (except for the fact I had to RESET it to properly boot) then I connected a DB9 to the YM2608 in order to use a joystick and I got interferences (wavy lines) on the screen.I shut down it and now all I get is a beep.
I also replaced all capacitors on motherboard (most of them were bad) but issue persists.How is it possible to damage the motherboard by only soldering some wires to the YM2608 sound chip?I'm still wondering how...

P.S.
My pc mounts an Overdrive CPU @83MHz, I read this is not really reliable.

P.P.S.
I dumped the BIOS (a NEC 27C4000) , tomorrow I will send it to MESS team

[SkyeWelse]

That sucks to hear Caius. I did take a look at that guide and it does give instructions for soldering directly to the YM2608. I wonder if it's possible that the chip got damaged somehow? Have you by chance desoldered the DB9 and booted it in it's original state?

If it is the chip there might be some places where a YM2608 chip could be still be ordered online, but likely in bulk.

Maybe if you took pictures of what the mod looks like now that could be of more help. I'm not an electronics person myself, but there are a few of us that are that might be able to give feedback or tips to try. I still need to replace the capacitors in my Ce2 as well. I'll be honest in that I'm kinda scared to do it, but it must be done if I want to preserve it.

Good luck with getting this working again!

-Thomas

[caius]

That sucks to hear Caius. I did take a look at that guide and it does give instructions for soldering directly to the YM2608. I wonder if it's possible that the chip got damaged somehow? Have you by chance desoldered the DB9 and booted it in it's original state?

If it is the chip there might be some places where a YM2608 chip could be still be ordered online, but likely in bulk.

Maybe if you took pictures of what the mod looks like now that could be of more help. I'm not an electronics person myself, but there are a few of us that are that might be able to give feedback or tips to try. I still need to replace the capacitors in my Ce2 as well. I'll be honest in that I'm kinda scared to do it, but it must be done if I want to preserve it.

Good luck with getting this working again!

-Thomas

Hi,
I fear the motherboard is fried.I soldered the wires directly to the YM2608 IC on the solderside and for that little I could play game it worked, I could correctly use my FM-TOWNS joypad connected to DB9.Then I got some scrambled white lines on screen so I immediately turned off the pc and removed the mod but now all I get is a beep.I'm a bit uncertain on what to do, if try to repair replacing the Overdrive CPU or accelerator card or put a new YM2608 (the best would be use a new motherboard but it's nearly impossible to get it) or get a new pc.Regarding replacing capacitors I higly recommend it since they were almost all bad, my PC-9821AP2/U8W uses strange SMT capacitors that look like tantalum but are electrolytic instead.Anyway thanks for your interest, I'll keep you informed about

[caius]

Here's the PC-9821Ap2/U8W BIOS dump (from a 27C4000 EPROM):

https://drive.google.com/file/d/0B0oZORLQc26xeXd0Y292QjFVYVk/edit?usp=sharing

[98digger]

Hi,
I fear the motherboard is fried.I soldered the wires directly to the YM2608 IC on the solderside and for that little I could play game it worked, I could correctly use my FM-TOWNS joypad connected to DB9.Then I got some scrambled white lines on screen so I immediately turned off the pc and removed the mod but now all I get is a beep.I'm a bit uncertain on what to do, if try to repair replacing the Overdrive CPU or accelerator card or put a new YM2608 (the best would be use a new motherboard but it's nearly impossible to get it) or get a new pc.Regarding replacing capacitors I higly recommend it since they were almost all bad, my PC-9821AP2/U8W uses strange SMT capacitors that look like tantalum but are electrolytic instead.Anyway thanks for your interest, I'll keep you informed about

The motherboard components are too small really for anyone to solder correctly (unless you had some really precise and professional equipment. I guess that in 1994, companies kept trying to shrink the technology any way they could, which unfortunately makes it hard for us people who actually enjoy things like the PC-98 to repair them.

I'm really sorry to see that your PC-98 is also experiencing hardware-related issues. But I guess, as people involved in the beginning of a new PC-98 fanbase, its kind of up to us to find out things like "the CD caddy can scratch the motherboard" and "Soldering the OPNA can wreck the motherboard" so that no future PC-98 owners have to deal with these problems.

Hopefully you can get your 9821 working again, as I am also trying to fix mine. The problem mine is having is most-likely fixable, however (it looks like all I have to do is reapply the solder mask, I see no trace cuts). Using multimeters to test the components is not really an option for PC-9821 owners (but probably is for PC-9801 owners due to larger trace/component sizes), however.

Could you maybe take some pictures of the soldering-job you did on the motherboard? I'll open my 9821 Ce2 and see where some of the traces near the OPNA lead to (you may have gotten solder on multiple traces at once and fried them; probably ones regulating the voltage going to the Chezrith chip, assuming that the insides of the Ce2 are similar to the Ap2). Like my Ce2, I'm pretty sure that if you remove all the solder and inspect the traces, you could possibly find and fix the problem.

Bye the way, does anyone know of any PC-98 programs that can test the hardware? Does the ITF test the hardware and, if so, how do I use it? I'm sure that if we could get a program like this running, PC-98 problems would be somewhat easier to find and fix.


Good luck!

-98digger

[98digger]

That sucks to hear Caius. I did take a look at that guide and it does give instructions for soldering directly to the YM2608. I wonder if it's possible that the chip got damaged somehow? Have you by chance desoldered the DB9 and booted it in it's original state?

If it is the chip there might be some places where a YM2608 chip could be still be ordered online, but likely in bulk.

Maybe if you took pictures of what the mod looks like now that could be of more help. I'm not an electronics person myself, but there are a few of us that are that might be able to give feedback or tips to try. I still need to replace the capacitors in my Ce2 as well. I'll be honest in that I'm kinda scared to do it, but it must be done if I want to preserve it.

Good luck with getting this working again!

-Thomas

I looked at the capacitors in my Ce2 today and noticed that they may be too small to be replaced easily, but I think I might have found a safer way to replace them. If no fluid has leaked from them, you could bend them upward, and cut the capacitor legs near where they connect to the actual capacitor. This would leave you with two legs sticking up out of where the cap was, and you could just solder the new caps onto the old legs. That way, you aren't actually touching the motherboard with the soldering iron. I'm pretty sure this would work, but you might want to check with someone who knows about caps and soldering before actually trying it on the real machine.