Transcript Bendix 55P3 Restoration - Tube Radio Restoration

Bendix 55P3 Restoration
Paul Pinyot.
KB3LZP
You have to clean the
shop some times! I
choose between units.
Typical AA5. A Bendix 55P3.
Model, manufacturer and
tube location on sticker.
Sometimes the model
number is inside or only a
chassis number.
Tape or Gum Band a
hard cardboard cover
on the speaker to
protect the cone.
Screws in a pill bottle
Label Antenna wires
Ohm out antenna coil. It is
part of a tuned circuit.
Check all coils and
transformers for bad
unopbtainium
IF continuity primary and
secondary. Use schematic to
find pins not in series with
capacitors integral to the IF
can.
Touch a 9 volt battery on the primary
of the audio output transformer. If
the speaker pops all is well. The
primary, secondary and speaker
voice coil. This does not work with
eletrodynamic speakers.
Record you results. Green for good, Red for
open
This is an emissions tube tester. Quicker
than a Mutual conductance. The tube must
work in the unit.
SHORT!
Do not power up
in chassis!
This tuning shaft oxidized
concaved area would catch
the dial cord. Remove and
sand smooth 220 grit emery
cloth
A dab of hi temp lithium
grease give control a
smooth feel.
Flush the tuning gang’s
ball bearings with contact
cleaner or denatured
alcohol and replace the
grease.
Mr. Jingles left
his mark here
!@#%
Two section 40uf
electrolytic capacitor.
Wax/paper
capacitors
Two caps of 40 uf 160
volts and one 200 uf
at 50 volts
4 post terminal strip that is
screwed to the chassis. Do NOT
use the 4th post as it is chassis
ground and not B- or circuit
ground.
These caps do NOT connect to
chassis ground! Two caps are
parallel to make up 40uf. The
other is a singe 47uf 160v
standard value.
New electrolytic cap array screwed
to chassis using original capacitor
lead wires.
This is an UL rated
safety capacitor
used for RF bypass.
This cap and a parallel
220k resistor are
connected from circuit
ground B- to chassis
ground and makes this a
This cap will be
replaced using
hooks. Clip the
cap close to the
body leaving all
of the lead wire.
Form a hook
with the needle
nose pliers to
receive the
complimentary
hook of the
replacement
cap.
The new
capacitor is the
same or slightly
larger in
capacitance and
is 630 volt rated.
These wax/paper caps
will only see up to 120
volts. 630 volts are
used simply because of
bulk purchasing
discounts and
minimizing inventory.
Place new cap lead wires
in hooks, form into
reverse hooks clip excess
and crimp.
Crimp
Crimped
Solder the
connection.
Alligator jumper used to mark
original capacitor’s lead
wires.
This comes in real handy for
interruptions like the phone or
lunch.
Spaghetti
insulation is
added. The
replacement
is smaller
than the
original.
These lead wires will be
curled on a stiff wire
and slipped over the
original lead wire in the
chassis.
Home made tool using an Exacto
knife handle and a cut off safety
pin.
Roll lead around
the pin.
Ends curled and trimmed. Slip
these over the original lead wires
and solder.
When heated the coil will
often slip under the original
spaghetti insulation. The
spaghetti may close up over
the coiled and solder splice.
To maintain a vintage
appearance restuff the
original capacitor.
This technique is used for a
“museum” level restoration. An
example is the $21,000, 16
tube Zenith 16-A-63
Stratosphere.
The new cap fits right into
the original cardboard. Use
paper slivers to fill the
space. Seal with wax or
Hot Melt glue.
Seal the ends
with Hot Melt
glue or wax, fresh
or original.
This radio did not
have its capacitor restuffed. This is only
how you would do it.
You can melt down
all the cut out caps,
that you have in
your big jar, to
maintain vintage
wax.
Shined up the cabinet with a power buffing wheel, rouge,
Novis Polish and Glayzit.