BASSMAN 100
SERVICE NOTES
1.
HORN REPLACEMENT
requires speaker removal in order to access horn wiring. If wire ties,
clamps, etc. are removed for ease of connecting/disconnecting horn wires, these must be replaced to
prevent buzzing at higher power levels.
2.
RIBBON CABLES
running between rear panel board and preamp board should be routed next to
the chassis, underneath the power-amp board.
3.
CHASSIS REMOVAL
is accomplished by first removing six (6) screws from the top, and one (1)
screw from each side of the cabinet; then slide the chassis toward the rear just far enough to provide
access to the speaker wiring.
Note: the speaker wires are bundled and shrink-wrapped with the
power transformer secondary wiring, and this configuration must be restored after servicing (for
safety compliance).
Locate the speaker wires (white goes to P1, black goes to P2 of the power-amp
board) and disconnect them. It will be necessary to cut the shrink wrap (take care not to cut the
transformer wires) so that the speaker wires can be pulled from the opening in the bottom of the chassis.
It should be noted that the speaker wires have been glued in place inside the speaker baffle (for sound
quality reasons), if this is disturbed during disassembly, it should be restored by removing the speaker, and
working through the speaker hole; leave sufficient slack to allow reassembly of the speaker leads to the
chassis.
For reference, the red wires from the transformer go to P3 & P5. The red/yellow wire goes to P4.
PARTS LIST
NOTE: SHADED ITEMS ARE FOR REFERENCE ONLY
PRINTED CIRCUIT BOARD ASSEMBLY - PREAMP
QTY PART # DESCRIPTION REFERENCE DESIGNATION
1
26517001
CAP AE AX 2.2uF 50V 20%
C40
2
38691001
CAP AE AX 4.7uF 50V 20%
C2 C6
9
25960001
CAP AE AX 22uF 16V 20%
C5 C13 C20 C25-27 C30-31 C33
1
38693001
CAP AE AX 47uF 16V 20%
C64
4
42001001
CAP CA 33pF 100V LL
C8 C19 C21 C32
1
39256001
CAP CA 68pF 100V LL
C22
1
38699001
CAP CA 100pF 100V LL
C39
2
39261001
CAP CA 330pF 100V LL
C11 C37
2
38703001
CAP CA .1uF 50V
C38 C41
2
51405003
CAP CD 120pF 500V 5%
C28-29
1
51960003
CAP CD 180pF 500V 10%
C1
16
34788003
CAP CR .1uF 50V 20% .2" LS
C44-45 C52-63 C65-66
1
27256003
CAP MPF .0015uF 100V 10%
C10
1
27257003
CAP MPF .0022uF 100V 10%
C23
1
27259003
CAP MPF .0033uF 100V 10%
C17
2
27260003
CAP MPF .0039uF 100V 10%
C36 C67
1
27261003
CAP MPF .0047uF 100V 10%
C18
1
27262003
CAP MPF .0068uF 100V 10%
C12
1
27264003
CAP MPF .01uF 100V 10%
C15
