BustedGear.com
Shop Repairs Manufacturers Resources IFAQs About
DIY Repairs
Amps
Ampeg
SVT CLASSIC
• shuts off
SVT-VR
• won't balance
Fender
DEVILLE
• bad input jack
MINI-TWIN
• convert to stompbox
PRINCETON 5F2-A
• re-cap
SUPER TWIN
• intermittent volume
Kay
703-C
• re-cap
Marshall
DSL100
• choke & o.t. install
Montgomery Ward
VALCO 62-9033
• 6973 tube substitute
• broken trem. control
Peavey
6505+
• tube filaments
CLASSIC-30
power resistor
Selmer
LITTLE GIANT MK 3
• loose transformer
Vox
AD50VT
• power resistor
VALVETRONIX
• pot replacement
Keyboards
Akai
MPC2000XL
• bad jog wheel
E-Mu
VINTAGE KEYS
• broken volume pot
Ensoniq
SQ-2
• battery change
Farfisa
MINI COMPACT
• divider problems
Korg
01/W
• keybed removal
KARMA
• key contacts
KRONOS
• key clacking
M1
• worn-out buttons
POLY-61
• envelope problems
• battery upgrade
TRITON
• disassembly
TRITON
• worn-out buttons
X3
• floppy drive belt
X3
• worn-out buttons
KEYS & CONTACTS
• m1, 01w, i2, i30, t3
• triton, trinity, oasis...
Kurzweil
PC88
• worn-out buttons
M-Audio
KEYSTATION
• broken USB jack
Moog
MICROMOOG
• dirty keys & controls
contour problems
• calibration & tuning
MINIMOOG
• key bushings
PRODIGY
• key contact cleaning
ROGUE
• broken power jack
Roland
D-50
• key contact cleaning
TR-808
• cracked ribbon cable
• worn-out switches
• new battery holder
JUNO-60
• battery upgrade
• key contacts
Sequential Circuits
PRO-ONE
• key contact cleaning
Vox
CONTINENTAL
• key contact cleaning
• drawbar problems
• new panel switches
Yamaha
MOTIF 6 & 7
• disassembly
MOTIF 6 & 7
• worn-out buttons
SY77
• battery change
KEYS & CONTACTS
motif 6/7, w5, kx76,
• dx7, sy77/85/99 ...
Technique
• IC Sockets
• Phone Plugs

Montgomery Ward 62-9033
Made by Valco
View
the
Repair
6973 Power Tube Substitution
6973 Tubes

9-Pin, 6973 beam power tubes are uncommon in guitar amplifiers but were commonly used in vintage jukeboxes by Wurlitzer, Seeburg and others.

Original 6973 tubes are now quite scarce.  A Russian remake is available but it's smaller and, to many ears, not as pleasing.

Among the vintage guitar amps using 6973 tubes are some 1950's - 60's amps made by Valco, many of them branded by Gretsch, Supro, Airline, Magnatone, National and Montgomery Ward.

On the right is one of the Montgomery Ward amps.

Montgomery Ward guitar amp

Its ID badge shows the complete model number:  62 GVC 9033A.

This model is equivalent to an Airline 62-9033.

ID Badge
View the Repair   >

The amp had one bad 6973 power tube and we wanted to install a pair of NOS American tubes.

It turns out, 6CZ5 tubes are quite similar to the 6973 in construction (see photo) and sound, and they aren't nearly as scarce.

We had to rewire the tube sockets slightly but afterward they accepted either tube type.

Tube Comparison

Besides the bad power tube, this Valco amp had a broken fuse holder (already replaced in this photo) and a broken shaft on the Tremolo Intensity control (right).

View the Repair   >
Shop       |       Repairs       |       Manufacturers       |       Resources       |       IFAQs       |       About

Page design and content Copyright © Richard Diemer - All rights reserved