National 158-LED Instructions Manual - page 7
7
c.
Replacing batteries:
Your microscope includes 3 rechargeable AA nickel metal hydride batteries. These may be recharged up to 500
times, but if you observe that a recharge is providing significantly less than 40 hours of operation. It is probably time to
replace to batteries.
Note that your microscope can be used during recharging. Simply turn “on/off” switch on back of microscope base to
“on” position and proceed as follows. In case of equipment malfunction, see “Troubleshooting” procedure.
IMPORTANT WARNING: DO NOT USE REGULAR ALKALINE BATTERIES IN THIS MICROSCOPE. ANY
ATTEMPT TO RECHARGE ALKALINE TYPE BATTERIES COULD RESULT IN BATTERIES EXPLODING.
Gently lay microscope on its side. Using a Phillips (cross head) type screwdriver, remove 5 each 3mm Phillips screws
from bottom of base. Remove base, observe black plastic battery case located on bottom of base. Carefully remove
Phillips screw that holds battery case together. Slide lid of case straight out to remove and expose batteries. Remove
all 3 batteries and replace with new rechargeable AA nickel metal hydride batteries, making certain to insert with
correct polarity according to markings on battery holder. Replace battery case lid and install base to microscope.
Follow instructions on new battery packaging to determine if they are already charged, or if they should be charged
before initial use. If recharging is required, following directions in “3.b” above.
d. Replacing LED element:
An LED “bulb” will last up to 50,000 hours, so you don’t have to do this exercise very often.
To open the illuminator field lens housing, use hex wrench supplied with your microscope to loosen hex screw on side
of lens housing. Remove lens housing to expose LED “bulb.” Remove bulb by grasping the plastic base of bulb and
gently pulling straight up. Insert new LED “bulb”, replace lens housing and tighten hex screw to secure lens housing in
place.
TROUBLESHOOTING
PROBLEM
REASON FOR PROBLEM
SOLUTION
Light fails to operate.
Batteries fully discharged.
Recharge batteries.
Batteries fully discharged and will
not recharge.
Replace batteries or replace
charger.
Rheostat control not turned far
enough.
Turn rheostat to increase light
intensity.
Light switch in off position.
Turn light switch on.
LED “bulb” burned out.
Replace LED “bulb”.
Image does not remain in focus
Stage of microscope drops from its
own weight.
Adjust tension control
Image does not focus
Slide upside down.
Place slide on stage with cover slip
up.
Slide cover slip too thick.
Use 0.17mm thick cover slip
(No.1 cover slip)
Poor resolution
Objective lenses dirty.
Clean objective lenses.
(image not sharp)
Eyepiece lens dirty.
Clean eyepiece lenses.
Too much light, iris diaphragm not
adjusted properly.
Adjust iris diaphragm.
Too much light, iris diaphragm
Not adjusted properly.
Adjust iris diaphragm.
Too much light when using 4x and
10x objective lenses, swing out filter
not in optical path.
Place swing in filter into optical path.
Spots in field of view.
Eyepiece or condenser lens dirty.
Clean lens. ***
Specimen slide dirty.
Clean slide.
***Spots in field of view can also result from dirt on inside of eyepiece. It is recommended that you have service
technician clean inside of lens.