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Details of Complete Restoration
Front
Panel (engraved panels only at this time)
 | Bead
blast to remove all existing paint |
| Sand
to smooth finish and fill-in any imperfections |
| Prime
and paint (usually satin finish gray) |
| Bake
the finish |
| Buff
and polish |
| Refill
engraved lettering
|
Knobs,
Dial Cover
| Bead
blast to remove old paint |
| Prime
and paint
|
| Refill
pointers on knobs (except Dial Lock and Calibrate knobs)
|
RF
Deck and Gear Train Reconditioning and Alignment
| This section includes the 2nd Crystal Oscillator section |
| Disassemble,
soak, clean, relubricate, reassemble, set split gear tensioning, properly
reset bandswitch timing. |
| Replace
all paper capacitors with Sprague Orange Drops
|
| Replace
C327 with NPO ceramic disk |
| Remove
slug racks and relubricate.
Realign slugs with cans upon reassembly. |
| Remove
RF and VIF coils
|
| Polish
all metal surfaces
|
| Re-solder connections in signal
path with silver-solder if solder connections are dull, including inside T207 and T208 |
| Add
any missing but necessary production
modifications (Prod’n Mod 2, 3, and 4)
|
| Check
resistor values and replace out-of-spec ones |
| Check
all tubes for both transconductance and noise |
| Tighten
all tube sockets and
metal-to-metal contact surfaces. |
| Apply
DeOxit to all tube and coil pins/sockets and to all wafer switch contacts
|
| Adjust
the calibration to zero-beat WWV |
| Align
all RF and VIF circuits, including the RF antenna balance (often overlooked) |
IF
Deck Reconditioning and Alignment
| Replace
all paper capacitors with Sprague Orange Drops
|
| Polish
all metal surfaces
|
| Check
all solder joints both under the chassis and inside the coil cans
|
| Add
any missing but necessary production
modifications (R504) |
| Check
resistor values and replace out-of-spec ones |
| Check
all tubes for both transconductance and noise |
| Tighten
all tube sockets and
metal-to-metal contact surfaces. |
| Apply
DeOxit to all tube and coil pins/sockets and to all wafer switch contacts
|
| Adjust
mechanical filter trimmer capacitors
|
| Neutralize
BFO circuit
|
| Stagger
tune IF coils
|
| Adjust
AGC coil for peak response
|
IF
Deck Options
| Optional:
Add the SSB/AGC modification (recommended) |
| Optional:
Add jumpers under 3TF7 socket to allow future replacement with 12BH7A
(recommended) |
| Optional:
Replace carrier meter potentiometer with a 10-turn precision potentiometer
(highly recoommended) |
| Optional:
If
the AGC oil filled capacitor is bad, a below-chassis replacement can be
installed or the new capacitor can be installed inside the existing can |
AF
Deck Reconditioning
| Replace
all paper capacitors with Sprague Orange Drops
|
| Polish
all metal surfaces
|
| Check
all solder joints and resolder dull or poor ones |
| Add
any missing but necessary production
modifications (Prod’n Mod 1)
|
| Check
resistor values and replace out-of-spec ones |
| Check
all tubes for both transconductance and noise |
| Tighten
all tube sockets and
metal-to-metal contact surfaces. |
| Apply
DeOxit to all tube and coil pins/sockets |
Filter
Capacitor Rebuild (C603 and C606)
| Cut
open can
|
| Clean
out inside of can |
| Cut
of connector stubs, drill, and tap |
| Add
small brass screws to aluminum posts to provide a reliable solder connection |
| Install
new components inside exiting can shells
|
| Reassemble
cans with J-B Weld |
PTO
Minor Refurbish with End Point Adjustment
| Polish
all metal surfaces
|
| Check
tube. If weak, substitute a strong but mature tube from another
location. Don't use a new tube here. |
| Tighten
all tube sockets and
metal-to-metal contact surfaces. |
| Apply
DeOxit to all tube and coil pins/sockets |
| Set
calibrate wheel to mid position with 35 KC at each end of bands
|
| Set
PTO endpoints. |
PTO
Options
| Optional:
Disassemble PTO, lubricate internals, renew desiccant, and reassemble.
Required if your Cosmos unit requires removal of one turn from internal coil
for proper endpoint adjustment. |
| Optional:
Adjust linearity throughout range on PTOs with external adjustment (i.e.
Cosmos) |
Power
Supply
| Polish
all metal surfaces
|
| Check
all solder joints |
| Check
all resistor values and replace out-of-spec ones |
| Check
tubes (if still in use) |
| Tighten
all tube sockets and
metal-to-metal contact surfaces. |
| Apply
DeOxit to all tube and coil pins/sockets
|
Power
Supply Options
| Optional:
Install diodes (3A, 1KV) and B+ dropping resistor, and return 26Z5W
rectifiers to owner
|
Chassis
| Polish
all metal surfaces |
| Remove
the covers from the antenna relay and apply DeOxit to contacts |
| Check
all solder joints |
| Check
all resistor values and replace out-of-spec ones |
| Relubricate
switches |
| Apply
DeOxit to all wafer switches and connectors and to antenna relay contacts |
Chassis
Options
| Optional:
Add CL80 inrush current limiter (recommended)
|
| Optional:
Install 3-prong power cord
|
Final
Alignment
Each
radio is operated for several hours before a full alignment of:
| 1st
and 2nd IF's (stagger tuned) |
| BFO
neutralization |
| Mechanical
filter impedance matching (where applicable) |
| Crystal
filters properly set (0.1 and 1 KC bandwidths) |
| 1st
and 2nd Crystal Oscillators peaked |
| Antenna
balance (often overlooked, but reduces common-mode noise significantly) |
| RF
alignments (twice) |
| VIF
alignments (twice) |
| IF
gain adjustment for maximum sensitivity |
| AGC
coupling |
| Carrier
Level meter |
| Sensitivity
Measurements (documented and graphed for your records and mine) |
| Optional:
Tweak sensitivity results via tube swapping and exchanges |
| Final
testing with weak signals and strong local stations, both SSB and AM |
Edited 12/17/2002
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