Editing IBM 5100 Maintenance Guide (section)

== Inspecting the Chassis ==

Inspection items (in order):

# '''PSU bulk filter capacitors''' — visual inspection for bulging tops, leaked electrolyte, or discolouration. Bulk caps on a 45+ year old linear supply are the highest-likelihood failure point.
# '''Series-pass regulator transistors''' — heat-sink-mounted; check thermal paste; replace if dried out.
# '''Flyback / deflection board''' — inspect for cracked solder joints around the flyback transformer (vibration over 45 years).
# '''DC300 tape drive belt''' — urethane perishes; if the belt is gummy, it must be replaced before any tape work.
# '''Keyboard''' — IBM beam-spring or capacitive sensing depending on revision; foam pads may have degraded.
# '''CRT''' — inspect for cracked phosphor, focus drift, weak emission (a fully warmed-up screen that's still dim indicates cathode emission loss).