Memory SIMMs must be installed in groups of fours, J10-J13 and J14-J17.
Make sure all SIMMs in a group of four are the same memory size. When installing the groups of four SIMMs, install the SIMMs in descending order beginning with slot J13 and ending with slot J10 or beginning with slot J17  and ending with slot J14.

My 41T had a nice suprise- eight NEC 428000A36FJ-70, IBM P/N 74G1020, FRU 73G3235. 32MB 70nS P, for a total of 256MB.

Tablet Connector Pinout

Pin	Signal	Pin	Signal
1	Ground	5	Receive from device
2	Direct Current	6	Transmit to device
3	(dc) Return (Ground)	7	Reserved
4	+5 V Reserved	8	Reserved

Key Mode Switch Pinout
   OK position    - No connections
   Lock Position  - Blue-Black
   Maint Position - Blue-Red

  Thank God this has only three pins.  Key Mode Switch assembly (lock/switch) is 88G2671. Cheap looking ABS plastic, BUT the keys and lock are made by 

Medeco Security Locks, Inc.
PO Box 3075
Salem, VA 24153

J19 External SCSI Enable

  Optional security for SCSI is provided by five jumpers (J19) on the system board. These jumpers (when set to the disabled position) prevent communication through the external SCSI connector. The default setting of the jumpers from the manufacturer is SCSI connector enabled.
 
 
 
 

MCA Riser 88G2949 FRU P/N 88G2731

J1,3,4 32 bit MCA slots J2 32 bit AVE slot J5 Local bus header

J6 Video card bus U5 88G2501 U6-9 Motorola MCM67M618FN11

My SWAG- U6-9 are the .5MB L2 cache.

88G2539 Riser card (without L2 cache)
88G2731 Riser card (with L2 cache)

Open Case
  Set the key mode switch to the Service position and remove the key from the key mode switch. Remove the three cover screws from the rear panel. Grasp both sides of the cover, and then slide the cover toward the front of the system unit until the cover stops (approximately .5 inch (12 mm)).
  Grasp both sides of the cover, and then rotate the rear of the cover upward until the cover is tilted at an approximate 45 degree angle. While keeping the cover tilted at an approximately 45 degree angle, slide the cover forward until the cover clears the front of the system unit, and then remove the cover.