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Power Base-2 & 800CSL Amplifier Service Manual
20
Module Information
MODULE HISTORY
Since its introduction in 1986, the PB-1 has gone
through a number of updates and revisions. Over the
course of its history some of these changes have
resulted in upgrading to newer modules. What follows
is a historical breakdown of PB-1 modules. It should
also be noted that the 460CSL was introduced in 1992
and therefor modules obsoleted before that time were
never used in the CSL version.
OUTPUT MODULES:
Q42647-0
Original Output Module. No longer available.
Q42717-1
Output Module: 12 resistor small predriver. Last out-
put module for PB-2 for use with TO-220 package
driver transistors.
Q42871-6
TO-3P Driver Output Module. Not for use in THC units,
not retrofittable into TO-220 driver transistor units.
Q42966-4
TO-3P Driver #2 Output Module. Not for use in THC
units, not retrofittable into TO-220 driver transistor
units. May replace this or Q42871-6 only.
Q43015-9
THC Output Module with TO-3P drivers. Not retrofittable
to any older units. Does not require special main
module for THC ODEP recompensation. Also im-
proved bias stability.
Q43203-1
THC #2 Output Module. Replaces Q42967-2 only.
Electrically identical, but larger screw head plates
prevent shorting which could occur with the first THC
output module.
MAIN MODULES:
Q42665-2
Original Main Module for PB-2. No longer available.
Q42683-5
Main #2 for PB-2. No longer available.
Q42818-7
Third Gain Main Module. Same circuit board as the
universal PC board used in MT-600/1200, MA-600/
1200, and PB-1 (Q42776-7), except that PB-2 re-
quired some unique component values. Added third
gain stage and ground lift switch. Can replace all older
modules. Note that if this module is being used to
replace an older module, you may have to slide the
ground lift switch to the left (ground lift position) and
clip off the plastic switch protrusion in order for the
module to properly fit in the unit.
Q43059-7
THC Main Module built on D 7993-5 circuit board. On
this module the boost circuit has been deleted, the
third position (1.4V) is added to the Sensitivity Switch,
and additional fault circuitry has been added to the
module. Although it is possible to modify any older unit
to accept this module, it is recommended that the
Q42818-7 be used to replace main modules in all older
units, and this module be used only as a replacement
for itself.