FM Towns II BP60PB60C CD-ROM and SCSI CDROM info

[sampson]

I've been working on repairing a FM Towns II MA and the last part is the CD-ROM which was unsuccessful. While the laser did burn out I grabbed pictures of all the components of the drive as well as identified all ICs/Capacitors I could. The motor for the CD-ROM is a Mabuchi RF-300PH-11400.

Gallery of pictures can be seen at https://imgur.com/a/fMIC1sH

IC/Cap list as follows:
CONTROLLER BOARD:
IC101 SHARP LZ95B32 9441U
IC102 TA7809F *3H

C101 16V 47uF
C103 6.3V 100uF
C114 16V 47uF

OPTICAL UNIT:
IC1 TECHNICS 8802SC 40.4
IC3 T94 17HB 4066BF
IC4 TECHNICS 8389S 499
IC5 C339G 9503RM18
IC7 358 446
IC9 TA78M05F *44
IC10 T94 22H 74HC74A
IC11 T94 27H 74H03A

C2 16V 22uF
C4 6.3V 100uF
C5 16V 100uF
C8 6.3V 100uF
C13 50V 1uF
C24 6.3V 100uF
C39 16V 47uF
C72 16V 47uF
C83 6.3V 100uF
C89 16V 47uF
C91 50V 4.7uF

As for the SCSI CD-ROM I came across a post on the internet which used the same driver used for the SCSI image here - http://ysflight.in.coocan.jp/FM/towns/cdsd/e.html

The difference however with this driver is that it provides fixes to CDSD.SYS and allows it to work perfect with CDDA. Since my CD-ROM is functional laser-aside I do not get the system halts with this setup unlike the previous image. There's still the same limitations as before with Ving games and various titles, I'm still investigating ways around that as a replacement laser doesn't seem possible. I also was able to restore the hard drive from the MA I purchased which came with a system setup for Towns OS 2.1 as well as Windows 3.1 including the capture software which is working with my card. It also has applications I haven't seen elsewhere like Photoshop 3.0 however I am working on cleaning out all identifying information before it can be posted. Currently I have it re-setup to take 2GB on SCSI2SD with a 128MB system partition, 800MB DATA/GAMES partition and 800MB Windows partition as well as moved the games from the SCSI image over to it.

Anyways I wanted to make sure this list made it somewhere and I can't be bothered to figure out how to post on a wiki so here you go.

[sampson]

It's also worth noting that the Towns II CD-ROM and Marty CD-ROM share the same laser. I was able to harvest the laser from my Marty and my drive now reads music cds/data but cannot boot cds.

Edit: The computer is now fully repaired! Turns out a utility I had used to decrease boot times was rendering the CD-ROM un-bootable. I use FT16 (https://www.vector.co.jp/soft/towns/hardware/se052966.html) to force my memory check to complete instantly as it has 100MB in it. Turns out the -F flag enables FIFO mode which breaks the CD-ROM booting.

Aaaaaaaand the laser stopped working already. God these things fucking blow.

[sampson]

So as far as the 2x cd-rom model is concerned I give up.

Fun things I've learned with regards to the fm towns cd-rom drive and the ever mythical laser:
All drives used the same mechanism that were black fm towns modules from what i can tell

All of these drives use the same optics which is misidentified as a RAE0111Z

laser has no real name however RAE0111Z is a full assembly with motor assembly that isn't actually drop-in

https://www.aliexpress.com/item/Replacement-For-PANASONIC-RXF-T600-CD-Player-Spare-Parts-Laser-Lens-Lasereinheit-ASSY-Unit-RXFT600-Optical/32898158368.html is an example of the laser in these drives and they're commonly listed as <blah> for some random cd player so searching is best done by looking up cd player optical pickup and referencing the capacitor layout on the ribbon cable

All of these drives are 16-bit and single speed

All white fm-towns and the marty have a 32-bit dual speed cd-rom with the unknown laser module

I have successfully transplanted a black towns drive into my MA so it is now tepairable and working. The only gotcha is the drive requires changing the cd-rom driver in Windows 95 as it is a 16-bit drive.

[parodius]

Wow lots of useful information and links here, thanks.

What's that bit about Ving games ?
Is that the reason why New Zealand Story needs a boot floppy to help it work properly on Martys ?

[sampson]

I haven’t looked at New Zealand Story specifically, is the boot floppy in neo kobe?

I’m still not fully certain on how fm towns handles IPL but have minimal grasp. From what I understand the system’s bios hands off to the cdrom to have IPL loaded and programs all have their own customized towns os environment. MS-DOS can’t recreate them all as there are various customized portions. For example Ultima 1-3 uses a customized font that is pure gibberish in DOS.

Part of the IPL process is the loading of tbios.bin that sets some portion of accessibility to the hardware. As an example on FM Towns II MA modes 15khz is not upscaled to 31khz while 24khz is. You can change a flag in TBIOS\TBIOS.INI which enables the feature but breaks window accelerators. Ving specifically use this portion of the IPL process to inject their own code which flat out does not work in MS-DOS.

[sampson]

Hey you know what? Just kidding about the earlier models having the easier to find laser. Turns out they ALL use that weird unknown laser except for the very first models. Oh well, it works now so I don't care.