General: 
 
Batteries/chargers
Common problems and known issues
RS232 output protocol

Circuit Diagrams (alphanumeric list):
 
C401
C420
C450
C600 / C601
C700
C720
C800 series
C800 Raystar LCD
C800 upgrades
C800 bell button connections

D60B - Judge's remote display with start/stop/bell/countdown buttons
D504
D505 / D605
D510 / D610
D510 digit replacement
D510 pcb replacement
DX display radio link


K10 bell
K11 bell
K20 display test set
K30 time-of-day clock / marathon timer
K60 remote start/stop/bell/countdown buttons
K506
K515
K530R - wire-free receiver
K530T - wire-free head
K530 aerial replacement
K531 / K532
K5xx - head trouble-shooting
K5xx - head testing procedures

Q232 RS232 interface

Miscellaneous drawings