Hammond C-3 Organ and Leslie 147 Speaker Repair Journal and Photos
by Chad Hauris, Retro Electronics and Audio Lab, Midland, TX. 4/30/06, Updated 5/28/06

This Hammond C-3 appears to date from the mid-late 50's and belongs to a church in Odessa. The C-3 and Leslie received a complete restoration job including replacing all capacitors in the Hammond amp chassis, re-doing the power line wiring, and adding fuses for better overload protection.

The Leslie amp received new 6550 and 12AU7 tubes and the paper and electrolytic capacitors were replaced. The motors were not working right so both of the motor mechanisms were completely dismantled, cleaned, re-lubricated, and re-wired. A new belt was installed on the top rotating horn.

Please click the pictures for larger views.


C-3 Hammond during repairs.
Front view of the C-3 during repairs.

Leslie speaker back view before repairs.
Rear view of the Leslie before repairs.

Leslie amp top view before repairs.
Leslie amp before repairs.  The cords going to the motors were in bad shape and were all replaced.

Underside of Leslie chassis before repairs.
Underside of the Leslie amp before repairs. The 10 K wirewound resistor, all electrolytic and paper capacitors, and the 6550 and 12AU7 tubes were replaced.

Rear view of Leslie cabinet with back off.
Rear view of Leslie with back off, before repairs.

C-3 Hammond amp before repairs.
C-3 Hammond electronics chassis before repairs.

New capacitors in C-3 electronics chassis.
New capacitors in electronics chassis.

Hammond c-3 electronics chassis with new capacitors.
New capacitors in electronics chassis (view 2).

Bad soldering at C-3 Hammond power line wiring.
Bad solder joints at the AC power input to the electronics chassis. A new power line cord was installed with a fuse.

Bad solder joints at C-3 power line wiring.
More sloppy soldering at the power line wiring. This wiring was all re-done. A 5 amp main fuse was added to the main power line and a 2 amp fuse for the electronics chassis.

Re-assembled upper Leslie motor.
Upper Leslie horn motor. The entire assembly was dismantled, all parts cleaned, and bearings re-lubricated.
Heat shrink tubing was used over the cloth covered wire for additional wire insulation protection and new power cords were installed.

The way the dual motor system works is that the large motor is the fast "Tremolo" speed motor and drives the horn belt through the pulley on top. When the switch is set to "Chorale", the large motor shuts off and the small motor turns on. When the small motor turns on, the shaft pops up and contacts the rubber drive wheel at the bottom of the large motor, thus providing a speed reduction drive through the large motor's shaft to the pulley.

When the small motor is off and the large motor is on, the small motor shaft retracts back out of the way.
The lower rotor motor received the same treatment.

Leslie amp after repairs.
Top view of Leslie amp after repairs, with new 6550 Electro-Harmonix tubes.

Side view of finished Leslie amp.
Side view of finished amp.

Leslie amp chassis with new capacitors.
Leslie amp chassis with new capacitors and resistor (left side).

Leslie amp chassis with new capacitors.
Right side of Leslie amp chassis with new capacitors.

Rear of finished Leslie cabinet.
Repaired motor at bottom of Leslie cabinet.

Upper Leslie motor repaired.
Upper Leslie motor re-installed.


Leslie amp re-installed in cabinet.
Amp reinstalled in cabinet with new motor power cords.

Finished C-3 Hammond console.
Finished C-3 console. A new "Start" switch, power indicator lamp, and power cord were installed.

Chad playing the C-3.
Chad playing the C-3.

Gregory playing the C-3
Gregory playing the C-3, returned to its church home.

Gregory playing C-3.
Chad and Gregory with the C-3.

Keyboard of the C-3.
C-3 Keyboards at church.

Side of the C-3.
Side view of Gregory and the C-3.

Leslie at the Church.
Leslie cabinet at the church.
Return to Organ and Piano Page

Retro Electronics Home Page