Complete Teardown, Cleaning/Lubrication, and Reassembly of the Olympus BH2-CH Substage Assembly
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used to clean most painted surfaces). Additionally,
many solvents will dissolve or damage plastic parts. Do
not allow untested solvents to contact the plastic
condenser-height knob or the plastic gear rack, as these
parts may be damaged by exposure to solvents. Before
using any solvent to clean plastic parts, test a small
amount of the solvent in an inconspicuous area of the
part (such as inside the knob) to ensure compatibility
with the plastic. Never use xylene to clean nylon parts,
as xylene dissolves nylon. Isopropyl alcohol and
trichloroethylene will cause swelling of nylon due to
solvent absorption. The list of solvents generally
considered safe for nylon includes acetone, diethyl
ether, heptane, mineral spirits, naphthalene, and
turpentine.
Common Problems with the BH2-CH Substage
A few of the more common problems which can affect
the BH2-CH substage assembly are discussed below.
Inability to Center the Condenser
Stiffness in the centering plunger or in the centering
yoke in the condenser-centering mechanism can cause
impaired condenser centering of the BH2-CH. This is
usually caused by dried, stiff grease in the centering
mechanism, and can be corrected by performing the
teardown,
cleaning/lubrication,
and
reassembly
procedure described in the relevant sections below.
Stiffness in the Condenser-Slide Mechanism
Stiffness in the condenser-slide mechanism can cause
damage to the plastic condenser-height rack if the
problem gets bad enough. This is usually caused by
dried, stiff grease in the condenser-slide mechanism,
and can be corrected by performing the teardown,
cleaning/lubrication,
and
reassembly
procedure
described in the relevant sections below.
Erratic Condenser-Height Adjustment
Erratic operation, no operation, or binding of the
condenser-height mechanism can be caused by dirt or
debris in the teeth of the pinion gear or in the teeth of
the plastic condenser-height rack, or by damage to the
teeth of the condenser-height rack. If the problem is
caused by dirt or debris in the teeth of the rack or
pinion gear, this can be corrected by performing the
teardown,
cleaning/lubrication,
and
reassembly
procedure described in the relevant sections below. If
the problem is caused by damage to the condenser-
height rack, this can be corrected by replacing the rack
1
,
but the rack should only be replaced as part of the full
teardown,
cleaning/lubrication,
and
reassembly
1
Parts for the BH2-CH, including the condenser-height rack, are no longer
available from Olympus.
procedure described below, since damage to the new
rack can be caused by dry, thickened grease in the
condenser-slide mechanism.
Teardown/Reassembly of BH2-CH Substage
The procedure for disassembling, cleaning/lubricating,
and reassembling the BH2-CH substage assembly is
described in the sections below. During the teardown
of the BH2-CH substage assembly, be sure to bag and
tag the various components, to prevent their loss and to
facilitate their proper identification during later
reassembly.
Remove the Condenser-Slide Assembly
The first step in the disassembly procedure is to remove
the condenser-slide assembly from the main housing of
the substage. To do this, use the condenser-height
knob to adjust the position of the condenser slide until
the hole in the condenser slide aligns with the slotted
stop screw (see
Figure 2 – Adjust condenser height until screw is visible
Next, use a suitable slotted screwdriver to remove the
M2.6x4 slotted stop screw (see
Figure 3 – Unscrew and remove the slotted stop screw
Rotate the condenser-height knob clockwise until the
condenser-slide assembly disengages from the bottom
of the main housing (see
