Troubleshooting; Optional Accessories And Parts - National 400 Instructions Manual

2. To replace bottom light (TBL models only), you will require National part #800-400, same as above.
Remove stage plate and observe lamp held in place by pressure clips in base. Carefully grasp bulb
and remove from clips by pulling straight out. Holding new bulb with tissue or cloth to avoid getting
body oil on lamp, push into pressure clips. Replace stage plate.
3. Replacement of fuse (TL & TBL models only).
The fuse is located at rear left side of microscope base. To remove fuse from holder, insert a 6mm
screwdriver blade into slot located in rear of fuse holder cap. Slightly depress and rotate screwdriver
¼ turn in direction of arrow, release pressure on screwdriver to release the fuse. Pull cap and fuse
out of fuse holder.
screwdriver, rotate fuse cap assembly in opposite direction of arrow until guide slot engages, depress
fuse cap and rotate ¼ turn to lock into holder.

TROUBLESHOOTING

PROBLEM
Light fails to operate.
(TL & TBL models only)
Unable to focus.
Poor resolution
(image not sharp)
Spots in field of view.
***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.

OPTIONAL ACCESSORIES AND PARTS:

This series is designed to provide optimum optical and mechanical performance at minimum cost.
Therefore, the design is "complete". It does not incorporate provisions for changes or additions (which
would increase manufacturing cost without increasing the basic good quality performance for which it is
designed). The only optional accessory available is WF15x eyepieces, which serve to increase
magnification by 50%.
#615-400 WF15X Eyepieces (pair)
#800-400 Replacement bulb, 12v 10w, for all illuminated models
#801-050 Replacement fuse, 0.50 amp, for 400TL 120v version
#801-100 Replacement fuse, 1.0 amp, for 400TBL 120v version
#903 Penlight illuminator (for 400-10-2 non-illuminated model only). Requires 2 each AAA
batteries (not included).
#940-410 Replacement frosted glass stage plate, 80mm dia. (405 Series only)
#941-410 Replacement black/white plastic contrast plate, 80mm dia. (405 Series only)
#941-460B Replacement black plastic contrast plate, 80mm dia. (405 Series only)
#941-460W Replacement white plastic contrast plate, 80mm dia. (405 Series only)
Insert proper fuse into fuse cap.
REASON FOR PROBLEM
Outlet inoperative.
AC power cord not connected.
Lamp burned out.
Fuse blown.
Head of microscope drops from
its own weight.
Objective lenses dirty.
Eyepiece lens dirty.
Eyepiece lens dirty.
Insert fuse cap into fuse holder.
Have qualified service technician
repair outlet.
Plug into outlet.
Replace lamp.
Replace fuse.
Adjust tension control.
Clean objective lenses.
Clean eyepiece lenses.
Clean eyepiece lenses. ***
7
Using
SOLUTION