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Restoring a Crosley Model D-25
Gerry O'Hara VE7GUH
October 2011
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Crosley Model D-25:
repaired & polished.
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Occasionally the SPARC Museum is delivered a real 'gem' for repair (or restoration). In this case a near cosmetically-perfect Crosley Model D-25 in the rather rare darker blue colour was brought in for electronic repair. This model is the epitome of early-mid 1950's design - akin to the car dashboards of the era and looking every-bit as good! The appearance of this model is quite striking, featuring two circular dials: one is an electric clock/timer and the other the tuning dial (with speaker fitted behind).
The radio's controls are simply tuning and volume, and the three controls on the clock allow the radio to be timed to switch off after a pre-determined period or switched on as per an alarm. This circuit also controls an appliance that can be plugged into an auxiliary socket on the side of the radio (eg. light).
The radio circuit is a simple, classic Broadcast Band-only 'All-American-Five' (AA5) design of the period, using a 12BE6 converter, 12BA6 IF amplifier, 12AT6 detector/1st audio, 50C5 audio output and a 35W4 rectifier. A loop antenna is fitted onto the rear panel and there is also a switch and phono socket to allow an external audio signal to be fed into the audio stages of the receiver.
This article is also available in PDF form.
Restoration
The radio was making noise when brought into the Museum - a sort of buzzing, cracking hiss, but not receiving any stations at all and the clock was not functioning either. Inspection below the chassis revealed two waxed-paper capacitors that were 'spilling their guts'- the insides of the capacitors were poking out of the ends. The original (can) multi-electrolytic had been removed from the chassis some time ago and replaced with a twin 30uF unit and a separate 8uF unit fitted below the chassis.
All electrolytics and paper capacitors were replaced and the resistors checked (all found to be within tolerance). The radio crackled when the tuning control was rotated, however, cleaning and re-lubricating the bearings on the tuning gang, plus some Deoxit applied to the contacts on the tuning gang soon cured that problem. The line cord was replaced with one having a polarized plug.
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Clock removed from the set.
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Clock motor bolted to rear
of clock mechanism.
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The clock motor proved to be open-circuit. Luckily a working D-25 clock motor was located in the SPARC parts collection and was installed into the set's clock mechanism. The motor assembly can be installed without removing the clock mechanism from the case, however, when testing the clock after fitting, it was found to be intermittent in operating the mechanism. On removal of the clock from the case the motor was found to be misaligned as one of the screws that hold the laminations together was preventing full engagement of the motor (the end of the screw is supposed to fit into a recess in the mechanism's rear plate). This corrected, the clock unit was re-installed - removal/replacement is simple - just remove the three small knobs and the three nuts from the bolts located around the periphery and replacement is simply the reversal of this, but watch out for the rubber ring that sits around the periphery of the clock: this could be quite perished (luckily not too bad in this particular set).
A quick polish of the case with Novus #1 and the job was complete - looks and works great.
Chassis before restoration ...
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... and after.
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A paper capacitor
'spilling its guts'.
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The Crosley badge.
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Rear of the set after
cleaning and repairs.
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