my PC-9801RA51
by quirble, last updated january 16 2025
the workhorse
initially i bought this machine with the excuse that i "needed another RA" to make sure my RA2's PSU wasn't dead. (it was dead). so after searching yahoo auctions i found a listing simply marked "PC9801RA Junk". hmm, what's this? "It won't start. It's junk. Before it died, it worked just fine"... interesting, a sudden failure?? looking through images, it had a PC-9801-26K soundboard, a PC-9801-55(compatible) SCSI card, a hard drive...? this machine was loaded! (i even found an expansion RAM card inside it!, giving it nearly 4mb of ram!) (and laughably somewhat cheaper than the RA2 despite having all this stuff, oops) so i got it.
when it arrived, it was almost impossibly clean. no dust or anything inside or out, basically no cosmetic issues! someone really cared for this machine. but when i tried powering it up... nothing. hm. yep, that seller didn't lie, this machine really won't start (just like the RA2!). in the meantime i ordered two sets of replacement capacitors for both the PU463 PSU out of the RA2, and this RA51, so i could at least get one machine working. this was my first mistake.
you see, the power supply in this machine was a Sanken PU463, not a Tokin PU463! that of course means IT'S ENTIRELY DIFFERENT! ･ﾟ･(｡>ω<｡)･ﾟ･ also, it had already been recapped, funnily enough - i noticed a little bit of burnt flux and some clearly not factory solder balls inside the board. odd, okay, let's try this PSU in the RA2. ...and of course it fired right up. okay??? now let's try the Tokin recapped PSU in the RA51! ...nothing. hm.
surely this machine wasn't... dead dead...? (｡•́︿•̀｡) the PSU wouldn't even do anything at this point. this was extremely similar behavior to an IBM PC/XT i had, which was solved by pulling an expansion board. i pulled both C-bus boards and boom, it fired to life. (the error turned out to be almost every tantalum capacitor on the 26K soundcard shorting to ground)
but it wasn't perfect. it wouldn't do anything when i tried using the keyboard, the colors were all wrong, etc. i looked up the symptom and apparently this was due to the dip switches being set incorrectly. (maybe the previous owner tried messing with them after it stopped working?) luckily the RA2 came with an owner's manual that detailed the correct dip switch settings, and after some trial and error, i got the machine to boot - not only to the "How many files(0-15)?" screen, but to the PC-9801-RA35L hard drive, which was still working!
there was a super primitive windowed file manager (from "TAXAN SYSTEMS Inc") pre-installed, as well as MS-DOS and tons of other cool random stuff! my plans for this computer are mainly just keeping it as clean as possible as sort of a "representation" of what people would do on their PC-98s - business stuff and windowed file managers during the day, and... strip hanafuda at night.
My 9801RA2 ｜ My 9801RA51 ｜ My 9821CX2 ｜ My 9821V166 ｜ other stuff