Alignment - Yaesu VL-1000 Technical Supplement

Introduction
The following procedures cover adjustments that
are not normally required once the amplifier has left
the factory. However, if damage occurs and some
parts must be replaced, realignment may be required.
If a sudden problem occurs during otherwise normal
operation, it is most likely due to component failure;
realignment should, therefore, not be attempted un-
less normal amplifier operation is thoroughly under-
stood, the cause of the malfunction has been clearly
diagnosed to involve part failure, and the faulty com-
ponent has been located and replaced.
We recommend that servicing be performed by
authorized Yaesu service technicians, who are ex-
perienced with the circuitry and fully equipped for
repair and alignment. If a fault is suspected, con-
tact the dealer from whom you purchased the am-
plifier for instructions regarding repair. Authorized
Yaesu service technicians will, at the completion of
the repair process, perform a complete performance
check to ensure compliance with all factory specifi-
cations.
Those who undertake any of the following align-
ment procedures are cautioned that they are doing so
at their own risk. Problems caused by unauthorized
attempts at realignment are not covered by the war-
ranty covering this product. Also, Yaesu must neces-
sarily reserve the right to change circuits and/or align-
ment procedures, in the interest of improved perfor-
mance, without notifying owners.
Required Test Equipment
The following test equipment (and thorough fa-
miliarity with its correct use) is necessary for com-
plete realignment. Correction of problems caused by
misalignment resulting from unauthorized adjust-
ments and/or made with improper test equipment is
not covered by our warranty. Although most align-
VL-1000 Technical Supplement
ment procedures documented below do not require
all of the listed test equipment at any one time, the
interaction of some adjustments may require that
more complex procedures must be accomplished lat-
er. Do not attempt to perform only a single step un-
less it clearly is isolated electrically from all other
steps. It is better to have all test equipment ready
from the beginning, and follow all of the steps in a
section in the order they are presented.
The following test equipment is required:
Ì
VP-1000 Matching Power Supply
Ì
FT-920 or other 100W transceiver
Ì
DC Ammeter
Ì
Control Cables
Ì
ALC (RCA-RCA) Cable
In-line Wattmeter (50 Ω, 2 kW)
Ì
(Connect between Antenna Jack 1 and 50 Ω
Dummy Load)
50 Ω Dummy Load (2 kW)
Ì
(Connect to In-Line Wattmeter)
75 Ω Dummy Load (2 kW)
Ì
(Connect to Antenna Jack 2)
Preparation & Precautions
A 50 Ω Dummy Load and the in-line Wattmeter
must be connected to Antenna Jack 1 during most
all procedures (except for the Reverse ALC Adjust-
ment procedure, which utilizes a 75 Ω Dummy Load,
which can be connected to Antenna Jack 2). Correct
alignment is not possible using an antenna. Except
where specified otherwise, the exciting transceiver
should be set to 14.2500 MHz, FM or (key-down)
CW mode, and the VL-1000 controls should be pre-
set as indicated:
Ì
OPERATE and REMOTE switches: both ON.
Ì
DIM, LOW, ATT, and TUNER: all OFF.
Ì
DISPLAY SELECT: MULTI-METER 1.

Alignment