Fender 68 Custom Deluxe Service Manual

‘68 Custom Deluxe® Reverb

ATTENTION:

WARRANTY SERVICE PROCEDURES

The “68 Custom Deluxe® Reverb Amplifier is considered to be field serviceable to the com­ponent level. As such stuffed PCB Assemblies are not readily available. Any Fender
Authorized Service Center in need of a warranty replacement PCB Assembly for this unit
should contact the Fender Customer Service Call Center, and ask to speak to an Electronic
Technician. You will be given instructions on how to proceed with the repair at that time.
Contact the Call Center by phone at [phone] or by email at [e-mail].

(This is the model name for warranty claims)

p/n 277-4000-000 (120V)

SERVICE MANUAL

Fender Musical Instruments Corporation, 17600 North Perimeter Drive, Suite 100, Scottsdale, AZ 85255-5440

Issued: October, 2013

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IMPORTANT NOTICE

 Copyright © 2013 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 CR = Ceramic Radial
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 MOX = Metal Oxide
RES WW = Wire Wound

‘68 Custom Deluxe

(This is the model name for warranty claims)

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 (**) indicate the

required 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

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Reverb

‘68 Custom Deluxe

3

(This is the model name for warranty claims)

Reverb

SPECIFICATIONS

Model Name: 68 Custom Deluxe Reverb

Release Number: PR 239

Part Numbers 68 CUSTOM DELUXE REVERB 120V 227-4000-000
68 CUSTOM DELUXE REVERB 110V TW 227-4001-000
68 CUSTOM DELUXE REVERB 240V AUS 227-4003-000
68 CUSTOM DELUXE REVERB 230V UK 227-4004-000
68 CUSTOM DELUXE REVERB 230V ARG 227-4005-000
68 CUSTOM DELUXE REVERB 230V EUR 227-4006-000
68 CUSTOM DELUXE REVERB 100V JP 227-4007-000
68 CUSTOM DELUXE REVERB 220V ROK 227-4009-000

Power Requirement: 100 W

Fuses: F 2A, 250V for 100V versions
F 2A, 250V for 120V versions
F 1A, 250V for 230V versions
F 1A, 250V for 240V versions

Input Sensitivity:

Input 1 High Level 10 mV – volume at maximum for 22 watts power. Tone controls centered.
Input 2 Low Level 20 mV – volume at maximum for 22 watts power. Tone controls centered.

Power Output: 22W RMS into 8 ohms @ < 10%THD, 1000Hz

Input Impedances >1M Ohms

Speaker Complement: 12”, 8 ohm

Dimensions Height: 17 1/2 in (44.5 cm)
Width: 24 1/2 in (62.2 cm)
Depth: 9 1/2 in (24.1 cm)

Weight: 42 lbs (19.05 kg)

Product specifications are subject to change without notice

®

‘68 Custom Deluxe

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(This is the model name for warranty claims)

SERVICE NOTES

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Reverb

CHASSIS REMOVAL is accomplished by first re-

moving the four (4) screws from the rear upper
panel. Unplug the white and red plugs on the Re­verb cable from the Reverb Input and Output
respectively and also the Internal Speaker Output

PCB EXCHANGE POLICY

Parts marked with a single asterisk (*) in the Part
Lists are not field replaceable. If a failure due to
one of these components is detected, please con-

CIRCUIT DESCRIPTION

This section provides concise information about new
or unusual circuitry designs incorporated into this
amplifier model. The purpose is to aid the service
technician by providing insight into the design areas
most likely to become obstacles in troubleshooting.
Information is focused for its effective use while
maintaining the security of Fender® proprietary in­formation wherever possible.

PRE-AMPLIFIER/REVERB

The preamplifier is configured in two parallel sec­tions – the Custom channel preamp & the Vintage
channel preamp.

For the Custom channel, the guitar signal is input to
J1 for high gain and J2 for lower gain. When both
inputs are used in a single channel, both signals re­ceive low gain. V1-A provides a single gain stage
that drives the tone stack. The Vintage channel tone
stack is composed of R7 and R8 and associated
components provide treble and bass tone control
respectively. R10 provides volume control. V1-B
provides gain lost in the tone stack.

For the Vintage channel, the guitar signal is input to
J3 for high gain and J4 for lower gain. When both
inputs are used in a single channel, both signals re­ceive low gain. V2-A provides a single gain stage
that drives the tone stack. The tone stack com­posed of R19 and R20 and associated components
provide treble and bass tone control respectively.

cable. Now remove the two screws (4 total) screws
on the left and right nickel plated chassis straps on
the cabinet top. Pull the screws completely out of
the cabinet. The chassis can now slide out to the
rear, giving access to the electronics.

tact the FMIC Customer Service Department to or­der the complete PCB Assembly.

R22 provides volume control. V2-B provides gain
lost in the tone stack.

The plates of V1-B and V2-B are tied in common.
This configuration allows both channels to utilize
the Reverb effect.

The output from V1-B & V2-B are fed via C12, cre­ating a high pass response to the REVERB drive
amplifier V3. The REVERB pan is driven by imped­ance matching transformer T1. The output of the
spring reverb signal is recovered and amplified by
V4-A. The V1-B & V2-B signal also couples to the
V4-B intermediate gain stage. This is the dry signal
which mixes with the wet Reverb signal at the grid
of V4-B.

TREMELO

V5-A is an R-C phase shift oscillator configured in a
classic vintage tube configuration. The oscillator
rate is controlled by SPEED control R42 in the first
leg of the phase shift network. The rate varies from
approximately 0.5 Hz to 5 Hz. V5-B amplifies the
oscillator output so that it drives either 1) the OP1
LDR opto-coupler assembly (for all non-European
models), or 2) the RoHS-approved LDR replace­ment PCB Assy (for European models). This circuit
modulates the input impedance of the non-inverting
input of the tube power amp. The modulating level
is adjusted with the INTENSITY control R48. This

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impedance modulation varies the effective input
level that drives the power amplifier.

POWER AMPLIFIER

Phase splitter V6-A&B is configured in a differential
long tailed pair topology with V4-B driving the non­inverting input and the feedback from the speaker
output attached to the inverting input. Output from
the V6-A drives the upper power amp tube V7. Out­put from the V6-B drives the lower power amp tube
V8. V7 and V8 act as a push-pull pair in the tube
class A-B power amplifier. T2 matches the 6L6 plate
impedances to the speaker load.

POWER SUPPLY

The line voltage is fed to T3’s primary through the
line fuse, F1, and the inrush current limiter, TH1.

‘68 Custom Deluxe

(This is the model name for warranty claims)

The red secondary output is full-wave rectified by
dual vacuum tube diode V9 and filtered to produce
the 415V (B+), 406V (Z), 324V (Y), and 270V (X)
DC supply voltages for the power and preamp
tubes.

A 6.3VAC secondary (green) powers the power in-

dicator lamp and the preamp & power amp tubes’

heaters.
The rectifier diode filament is supplied by a sepa-

rate 5.4 VAC secondary winding (yellow).
Negative bias for the output tubes is supplied by the

solid state half-wave rectifier CR1, a resistive divid­er circuit (R69, R58 and R59), and two filter
capacitors (C36 & C29). R58 is used to adjust the
output tube stage bias voltage to nominally set the
V7 & V8 idle currents at 24 mA for each.

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Reverb