Wurlitzer 1900 Jukebox Repair Journal, Page 2: Amp
Repairs
by Chad Hauris, Retro Electronics and Audio Lab, Midland, TX. 12/24/05
Page 1:
Wurlitzer 1900 Before Repairs
Page 3: Mechanism
and phono cartridge.
Page 4: Lighting and Electrical Wiring
Wurlitzer
Jukebox Page
Retro Electronics Home Page
The Wurlitzer 1900 amp had a lot
of corrosion and oxidation on it. We
tried a variety of solvents and found that Rid-Ox from Tech Spray was
the best at removing the corrosion. We were not able to remove all of
the oxidation but we did improve it a lot.
Top of amp before repairs.
Bottom of amp before repairs.
We replaced all capacitors, added a new power cord and mains fuse
holder, installed a new silicon bridge rectifier, and new tubes.
Top of amp after repairs.
Bottom side of amp after repairs.
New silicon bridge recitifier. A previous owner had installed 4 silicon
diodes under the chassis to replace the old selenium unit, but none of
the connections had been soldered! This new unit we installed is a 25
amp 400 PIV rectifier.
Here is the modification used to allow the amp to work with the
magnetic cartridge and preamp. We disconnected the .1 mfd capacitor
between the plate of the Cobra oscillator stage and the grid of the
6AN8 tube. The phono input jack was disconnected from the Cobra circuit
and connected through the .1 mfd cap to the 6AN8 grid circuit.
Page 1: Wurlitzer
1900 Before Repairs
Page 3: Mechanism
and phono cartridge.
Page 4: Lighting
and Electrical Wiring
Wurlitzer
Jukebox Page
Retro Electronics Home Page
