Specs of the machine  is as follows
W x D x H:  36cm x 40cm x 9.4cm ( including rubbers on each bottom corner)

CPU      : DX2/66 or DX4/100, PODP ready.
socket3 ZIF, VRM not required, switchable   5V <-----> 3.45V using  6 x 2 jumpers..
System Clock- base clock is changeable  66MHz<----> 50MHz 

Jumper J50	Bus Clock
Pins 1-2	50MHz
Pins 2-3	66MHz

Memory : 4 simm slots. accept up to 32MB parity per slot max system memory 128MB

Video    : S3-864 1MB VRAM up-gradable to 2MB ( 2 DIP type sockets locates just beside of on-board VRAM like PC750 ) Original parts used in my machine are KM416C256BJ-6

L2 cache : 128KB silk shows 128K L2 SUPECACHE IBM 85G4865 labeled as EC:D61570B. also labeled IM96A003544 85G4865 498 Writeback/Writethrough selectable by jumper. CHIP is  SONY CXK78486 1Q-33 448B38EZ. it has also a marking " 80G5454" as if it is a IBM parts. (Ed. working on an outline)

Drives    : 1FDD, 1HDD drive bay,  (Sizes?)

CD-ROM drive bay (custom CDD required, slim hight and short depth )  I'm using a Toshiba 4x drive;  XM1202B, which is for notebook PCs (or laptops). EIDE interface.  This drive has a mini connector used in IDE 2.5" harddrive. so it is easy to connect to the standard-sized IDE cable using converter. One defect...its color. Gray color used in Toshiba laptops breaks the total atmosphere of my machine....

Bus slots Available : PCI/MCA shared slot x1,  MCA slot x1
>     ******modified ISA slot x1 for special PCMCIA /A with 2 sockets******.

E-IDE Controller.  I'm using 6.4gig seagate drive but not sure about the maximum capacity which this machine can handle.

Micro PCI Connector (?) 
   Further more this machine has a very unique connector onboard which is called Micro PCI connector. Only two devices are available for this connector, one is Micro PCI Ethernet /A and the other is of course Micro PCI TokenRing /A.  I unfortunately have never seen these adapters. One of my net-friend has one for Ethernet and  I really want to get TokenRing /a.

Small PCI vs. Micro PCI
   I do not know it is world-wide standard or not, but according to my friend, this connector was introduced as " kogata  PCI" in IBM's leaflet issued when PC720 was announced. In Japanese,  "kogata"  stands for "small" rather than " micro" though these two words are nearly same. So I think  " Small-PCI interface" would fit to this connector. 

(Ed. I have seen ONE adf for an adapter which hinted that it was a flippable PCI/MCA like the DCA ISA/MCA or the ATI 8514/A Ultra)

PCMCIA Adapter (s) 
   You may feel very strange with the adapter used in above mentioned machine.  The adapter of course has ISA connector edge to mate with the bus above. and  same adapter  is used for PCI/ISA  version of PC720.
(Ed. There is an ISA 2 slot adapter version of the PCMCIA Adapter /A)
    Adapter  has 2 PCMCIA sockets on the card and additional 2 devices are available through the connectors placed on motherboard. The PCMCIA controller chip is 54G0574 , compared with the 34G3547 used on the PCMCIA Adapter /A.

   The 2 slot MCA PCMCIA /A is not popular item here in Japan.I've never seen the adapter ever except the photo image in Don Peter's collection) .

PCMCIA Woes
    According to my  friend,  PCMCIA sockets of PCI/ISA version could be  used properly on Win98.  Hearing his comment, we all expected that  the problem was solved and developed driver was presented by  M$ or IBM Japan. But our poor PCI/MCA version couldn't run in protected mode and still  uses real mode driver only.
    This situation is same with TP720C. I have one but not yet checked inside of the machine. Anyway it is completely same  with yours. TP700/720 series were designed and manufactured in Japan conducted under Yamato research center and manufactured at  both the Fujisawa and  Nozu factories.