SERVICING INFORMATION
THE INFORMATION THAT FOLLOWS IS INTENDED FOR QUALIFIED SERVICE TECHNICIANS.
Locating the Test Points
Whenever possible,
take the voltage readings on the large connector on the
main printed circuit board. You will have to remove the front cover to access
it.
The DAX60 has a single 16-pin connector labeled "T" on the schematic; the
pins are numbered from bottom to top on the board.
The DAX120 has two 16-pin connectors: the top connector and the top half
of the bottom connector are referred to as "Jl" on the schematic, and the rest
of the bottom connector is referred to as "J2" on the schematic. The pins are
numbered l-24 and l-8, from top to bottom on the board.
Measuring DC Voltages
DC voltages are printed in rectangular boxes at various points on the
schematic. When measuring these voltages on the amplifier, use a DC meter with
a resistance of 1 megohm per volt and proceed as follows:
Step 1.
Place the amplifier on a suitable work surface and make sure that no
signal is present at the input terminals. Disconnect the speakers and con-
nect a suitable resistive load in their place:
DAX6O: The load should have at least a 60-watt power rating and a value of
10.4 ohms across the 25-volt output or 83.3 ohms across the 70.7-volt
output).
DAX120: The load should have at least a 120-watt power rating and a value of
5.2 ohms across the 25-volt output or 41.6 ohms across the 70.7-volt
output).
Step 2. Plug the amplifier into a 120-VAC, 60-HZ source.
Step 3. On the DAX6O: Connect the meter's negative lead to the amplifier common
at Connector "T-14." As you locate each DC voltage on the schematic,.note
the number of the nearest "T" terminal in that leg of the circuit and, if
possible,
take the readings between such a "T" terminal and "T-14."
On the DAX120: Connect the meter's negative lead to the amplifier common at
Connector "J1-13."
As you locate each DC voltage on the schematic, note the
number of the nearest "J" terminal in that leg of the circuit and, if possi-
ble, take the readings between such a "J" terminal and "J1-13."
Measuring AC Voltages
AC voltages are printed without boxes at various points on the schematic.
When measuring these voltages on the amplifier, use an AC meter with a one-
megohm impedance and proceed as follows:
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