COBRA schematic diagram service manual circuit diagram wiring schema repair instruction guide user manual free pdf download

 Digital DC Voltmeter (high-Z, 1 M-Ohm/V)
 DC Ammeter
 RF Millivoltmeter
 AC Voltmeter
 RF Standard Signal Generator w/calibrated output and dB scale, 0 dBμ = 0.5μV
 Signal Generator with calibrated output
 Spectrum Analyzer good to at least 1 GHz.
 Frequency Counter
 50-Ohm Dummy Load (200 watts)
 100-Ohm Dummy Load (200 watts)
 150-Ohm Dummy Load (200 watts)
 In-Line Wattmeter (200 watts, 50-Ohm)
 Linear Detector
 RF Coupler

Alignment Preparation & Precautions

A 50-ohm RF Dummy load and in-line wattmeter must be
connected to the main antenna jack in all procedures that
call for transmission, except where specified otherwise.
Correct alignment is not possible with an antenna.
After completing one step, read the following step to determine
whether the same test equipment will be required.
If not, remove the test equipment (except dummy load
and wattmeter, if connected) before proceeding.

Correct alignment requires that the ambient temperature
be the same as that of the transceiver and test equipment,
and that this temperature be held constant between 68 °F~
86°F (20°C ~ 30°C). When the transceiver is brought into
the shop from hot or cold air, it should be allowed time to
come to room temperature before alignment.

Whenever possible, alignments should be made with oscillator
shields and circuit boards firmly affixed in place.
Also, the test equipment must be thoroughly warmed up
before beginning.

Note: Signal levels in dB referred to in this procedure are
based on 0 dBμ = 0.5 μV (closed circuit).

Under no circumstances should any alignment be attempted
unless the normal function and operation of the transceiver
are clearly understood, the cause of the malfunction
has been clearly pinpointed and any faulty components
replaced, and the need for realignment determined
to be absolutely necessary.

The following test equipment (and thorough familiarity
with its correct use) is necessary for complete realignment.
Most steps do not require all of the equipment listed,
but the interactions of some adjustments may require
that more complex adjustments be performed in a sequence.
Do not attempt to perform only a single step unless
it is clearly isolated electrically from all other steps.
Rather, have all test equipment ready before beginning,
and follow all of the steps in a section in the order they
are presented.