First post, by Pawlicker
- Rank
- Newbie
So here's the thing, for the past year or so I've gotten back into PC-98 collecting. I originally dabbled with it in the mid-2010s with a Ce2 and later a V16 (which didn't have a sound card) and I never exactly had money to spend on it. Unfortunately I wound up getting money from a job. I first wound up buying a PC-9821Cx3 which proved to be a mistake as I've wound up getting everything from a H98 to a PC-9821 laptop. However none of the PC-98s I got had a YM2608b based PC-9801-86 sound card, either installed or onboard. This is important as compatibility is better with these cards. It's not like you can find them in PC-98s for sale anymore if they're not built-in, they wind up getting pulled out as the sound card can go for more than a PC-98 with one installed.
I decided I wanted a 98MATE A model (or A-Mate, depending on where you go online) but the problem is nearly all of them have bad cap leakage. So I decided to do something stupid and I bought a PC-9821An. The An is a very weird model, featuring Intel cache chips (like PS/2 machines) and as a result the bus is locked at 60mhz. Furthermore the motherboard is very notorious for being hard to upgrade without instability issues. Basically if you want a faster PC-98, it's a lot easier to buy a regular Socket 5/7 model. I wound up buying a 9821An on Yahoo Japan tested to post only, with two floppy drives (some booters require this) and I ended up swapping a HDD carrier from a 9821Ae in it as well. The first thing I noticed once I got it plugged in was the system came with the infamous FDIV bugged Pentium chip, which I would later swap out for a Pentium 100 with the bug fixed.
Surprisingly the machine worked, but the sound section caps and motherboard were starting to leak, so I recapped that section of the board. It was a mess but I was able to get it done even after a trace detached from the PCB but didn't break. Unfortunately the system has rust on the ports and whatnot but the motherboard of this machine is truly weird. Instead of a true Intel chipset there are numerous NEC custom ASICs and I mean tons of them. There's even a daughterboard PCB with GALs on it as well. I also read that you had to replace 2 caps in the cache area so I did those. The reason the caps are bent in the image is also because the power supply literally clips onto the motherboard as well, and it's also known that if you use a CPU upgrade that grabs voltage from a floppy drive connector you can actually burn out the motherboard due to how the PSU regulates itself when it's not having 3.3v drawn from it. If you're curious what's on the board, this site has a diagram of it commented.
The machine worked after the recap, it's just not good for Windows 95 as you're stuck with only 256 colors unless you install a window accelerator card that works similar to the old 3dfx cards (you plug in the onboard video to that card and it switches over) but it's great for DOS stuff. The reset switch also physically does not function and the volume pot doesn't work properly unless you "push" the pot in physically. But it works and here it is next to my H98 (another oddball machine, with a high res DOS prompt).
