Bullet 15 DSP Schematic

(This is the model name for warranty claims)

SERVICE MANUAL

BULLET® 15 DSP

p/n 2267700020 (120V)

CONTENTS:

Notices .............................. 2

Specifications.................... 3

Service Notes.................... 4

Circuit Description............. 5

Parts Lists:

PCB Assembly............ 6

uDSP Assembly ......... 8

Chassis Assembly ...... 8

Cabinet Assembly ...... 9

End Item Assembly .... 9

Service Diagrams ........... 10

Fender® Musical Instruments Corp. 8860 East Chaparral Road Suite 100 Scottsdale, AZ 85250

June, 2002

IMPORTANT NOTICE

2

BULLET® 15 DSP

(This is the model name for warranty claims)

Copyright © 2002 FMIC. All rights reserved. All
information contained herein is CONFIDENTIAL
and PROPRIETARY and is the property of Fender®
Musical Instruments Corporation. It is not to be
sold or assigned to another party and is disclosed
solely for use by Fender Authorized Service Cen­ters for purposes of product service and
maintenance. All information is not to be disclosed
to others without the expressed permission of
Fender® Musical Instruments Corporation. All

PARTS LIST CODES

The description codes used in the itemized Parts Lists are defined below:

CAPACITOR CODES

CAP AE = Aluminum Electrolytic
CAP CA = Ceramic Axial
CAP CD = Ceramic Disk
CAP MPF = Metalized Polyester Film
CAP MY = Mylar
CAP PFF = Polyester Film/Foil

RESISTOR CODES

RES CC = Carbon Comp
RES CF = Carbon Film
RES FP = Flame Proof
RES MF = Metal Film
RES WW = Wire Wound

specifications are subject to change without notice.
This information and any copies produced elec­tronically or otherwise must be surrendered upon
demand of Fender Musical Instruments Corpora­tion.

Parts marked with two asterisks (
quired use of that specific part. This is necessary
for RELIABILITY and SAFETY requirements.

DO NOT USE A SUBSTITUTE!

HARDWARE CODES

BLX = Black Oxide
CR = Chrome Plated
HWH = Hex Washer Head
M = Machine Screw
NI = Nickel Plated
OHP = Oval Head Phillips
PB = Particle Board
PHP = Pan Head Phillips
PHPS = Pan Head Phillips Sems
SMA = Sheet Metal "A" Point
SMB = Sheet Metal "B" Point
SS = Stainless Steel
TF = Thread Forming
ZI = Zinc Plated

) indicate the re-

**

SPECIFICATIONS

Model Name: Bullet 15 DSP

Release Number: PR 241

(Not a model number)

Part Numbers (120V, 60Hz) US: 2267700020

(110V, 60Hz) TW: 2267701020

(240V, 50Hz) AUS: 2267703020

(230V, 50Hz) UK: 2267704020

(230V, 50Hz) ARG: 2267705020

(230V, 50Hz) EUR: 2267706020

(100V, 50/60Hz) JPN: 2267707020

(220V, 60Hz) ROK: 2267709020

3

BULLET® 15 DSP

(This is the model name for warranty claims)

Power Requirement: 38W

Power Output: 15W RMS into 8 ohms @ 5%THD

Nominal Input Level: 100mV for 15W into 8 ohms @ 5%THD

Impedances Input (Pre-Amp): 1M ohms

CD Input: greater than 30k ohms

Speaker Complement: One (1) 8", 8 ohm,

Fender Special Design Speaker
(P/N 0025421000)

Dimensions Height: 12.4 in (31.4 cm)

Width: 13.25 in (33.7 cm)
Depth: 7.13 in (18.1 cm)

Weight: 15 lbs (6.8 kg)

Product specifications are subject to change without notice

(This is the model name for warranty claims)

SERVICE NOTES

4

BULLET® 15 DSP

1. CHASSIS REMOVAL is accomplished by first

removing four (4) screws from the Rear Cabi­net Panel and two (2) screws from the top of
the Cabinet; detach the speaker wires from the
speaker and then slide the Chassis toward the
rear of the Cabinet.

2. uDSP PCB ASSEMBLY REMOVAL is accom-

plished by disconnecting the Ribbon cable on
the uDSP PCB Assembly, releasing the tabs on
each of the plastic Stand-offs which the uDSP
PCB Assembly is mounted. Removal of the
uDSP PCB Assembly may be necessary should
any of the Digital Effects operate improperly.

PCB EXCHANGE POLICY

Parts marked with a single asterisk (*) in the Part
Lists (starting on page 9) are not field replaceable.
If a failure due to one of these components is de­tected, please contact the Fender® Dealer

3. BULLET 15 DSP MAIN PCB REMOVAL is ac-

complished by removing the following items: All
Knobs, one (1) screw at the CD Input Jack, two
(2) nuts and washers at the Input and Head­phone Jacks, two (2) screws at the Heatsink
which attaches to the Chassis. Desolder the
Transformer Leads at P1, P4, P5, P6 and P7.
Disconnect the Yellow and Black wires at the
Power Switch leading from P2 and P3. Discon­nect the Ribbon Cable at P8.

Customer Service Department to order the com­plete PCB Assembly.

CIRCUIT DESCRIPTION

5

BULLET® 15 DSP

(This is the model name for warranty claims)

This section provides an overview of any new or
unusual circuitry incorporated into this amplifier
model. The purpose is to aid the service technician
by providing insight into the design areas most
likely to present a challenge in troubleshooting.
This overview is focused for the efficient use and
security of Fender® proprietary information.

PRE-AMPLIFIER

The guitar input signal is fed into the high pass filter
at U1–B before splitting into two signal paths. The
Normal Channel signal path (U1–A to U3–B) is ac­tive until the Drive Select switch is pushed “IN” to
change the signal path from the Normal Channel to
the Drive Channel (U2–B to U3–B). Differential
amplifier U4–A and follower U4–B adjust the signal
level and provides +1.65VDC bias voltage to the
uDSP effects card. The preamp is in series with the
digital effects card, therefore, disconnecting the
card breaks the overall signal path. The signal from
the uDSP card is recovered at U6–A. It is neces­sary to bring the signal back to its level prior to
entering the uDSP card. This is accomplished by
increasing the signal gain at U6–B. The signal is
fed through the Passive Tone Control circuitry to the
summing amplifier at U3–A, where it is mixed with
the CD/Tape Input. The signal is fed through the
Headphone buffer amplifier (U8–A and U8–B) and
on to the Power Amplifier. FET Q2 is used to mute
U6–A at power shutdown, preventing any uDSP
card signal transients from getting through to the
Power amplifier.

POWER AMPLIFIER

Current Feedback topology is used for the Power
amplifier. The Power amplifier IC (U5) is configured
as a non-inverting amplifier. Diodes D7 and D8 are
used for common-mode protection of the amplifier.
Current feedback is achieved by sampling current
at the negative speaker terminal and feeding the
signal back to the inverting node of the Power am­plifier through R41 and series capacitor C25. The
negative speaker terminal is referenced to ground
through resistors R42 and R43. FET Q1 provides a
mute function at the Power amplifier input.

POWER SUPPLY

Standard bridge rectifiers for high voltage (+/-22V),
with zener regulation (D14–15) for the +/–15V sup­plies. +15V supplies U7, 7805 regulator for +5V
supply for the uDSP card and digital user–interface.

DIGITAL USER INTERFACE

The uDSP Effects control (R65) is a linear pot that
sets a DC level (0–5V), which is read by an A/D
converter located on the uDSP card. These DC
levels determine which desired Effect is selected.

DIGITAL NOISE

The uDSP effects card generates some high fre­quency noise (>50kHz), which is a normal product
of DSP processing. This does not affect amplifier
performance, but may be visible when observing
the output of the amplifier on an oscilloscope.

.