Does it reset (do a little movement) right at the start of booting, just before/after the beep?
A jumperless drive can be set to be drive B:
If in basic and disk is inserted type:
Files "B:"
I don't know if sony 900s require the ready signal. They can however work with drives which have that signal set. To achive that short pin 34 to pin 33. Can be done on the mainboard, in the cable and on the diskdrive. In the cable could be easiest since that would not require soldering, in case that's not your thing.
It was continuously lit the first time, when I inserted the cable the way it fit into the original drives. So this port is upside-down in comparison to the original drives. It stopped being continually lit after I flipped the cable, and then my computer would boot again. My replacement drive is also a Mitsumi.
There are no visible jumpers, and I don't solder.
Even though I just pulled this drive out of shrink-wrap, I don't even know for sure if it works. I guess I'll have to put it in a PC to determine if it's even a working drive.
Drive does work in older PC. I put in a Disc Station and loaded the files on a Windows 2000 machine. So I'm trying to figure out how to jumper and it seems like wrapping a thin wire on the pins on the drive might be the easiest way. I'd prefer not to modify the cable since it's made for the MSX and I wouldn't put it past myself to screw it up.
If you are sure you can wire pin 34 and 33 together without touching pin 32, that would work.
PCs normally do not use A: / B: jumper settings but cable select.
If the drive works in a PC can't work as is in the MSX. If there're no jumpers and you can't solder, you need to apply some changes to the cable to make it (probably) work:
1) Using a little flat screwdriver, carefully disassemble the cable female header you connect to the floppy and swap cables 10 & 12. Be careful, don't swap the wrong cables. Note: pin 1 is usually marked with a red line in the cable.
2) From the same connector, leave unconnected cables 33 & 34.
3) Remount again the female connector with the above cables left out.
4) Peel both cables and twist them, joining 33 & 34. Apply some non-conductive tape
Try it, now you have a drive A: with a constant READY signal. Not great; but usually works fine enough.
I feel pretty confident that I have the pins jumpered successfully, as long as I got the right pins. I have still not been able to boot from a floppy, and I'm having more problems with the MSX.
It boots with a red screen and "@ D" underneath the MSX logo. If I wait a long time and then press enter, it will flash a couple colors on the screen before going black. Shift + F1 doesn't work.
If I put a cartridge in, and I wait a minute on the logo screen, I can load the cartridge by pressing a key.
If I put a disk in, I do hear it spinning which I don't think it was doing before. However, it will not boot the disk. I've tried a few. Singular Stone, which is new, and a couple Disc Stations and Peach Ups that I checked for mold before inserting.
I think I mentioned it before but it seems your battery (the one that holds the RTC content like clock and screen settings) is dying. It is probably best to remove it, surely your MSX will com back to live afterwards.
