Restoring a Marconi Model 142 Table-Top Radio
Gerry O'Hara VE7GUH
Sep 2008
 

 

Restored Marconi 142.
 
 
This Marconi Model 142 table-top dating from 1938 was acquired from a local second-hand store and was in rather a sorry state, with the cabinet having been the subject of long-term abuse from a plant pot or similar. This had resulted in bad discolouration and warping of the veneer on the upper surface, with some areas becoming detached from the underlying plywood. The chassis was also in a poor state: rusty and with many tired-looking components. Even so, the set looked like it had potential and those Marconi dials look just great when lit-up...

The chassis and speaker were removed and the cabinet taken to SPARC as a Sunday afternoon project there for a few weeks. The old lacquer was painstakingly scraped off (no stripping chemicals were used), the detaching and warped veneer glued down, and the surface prepared for re-lacquering by sanding with lemon oil as a lubricant. Three coats of shellac were then applied, each being rubbed-down with super-fine steel wool. The cabinet was then masked, exposing only the shoulders, front trim strips, flutes in the lower front panel trim strip, magic-eye/dial cut-outs and the edges of the loudspeaker cut-outs. These areas were sprayed with several coats of dark brown semi-gloss lacquer to act as accents as per the original finish. Once this stage was completed, the masking was removed. Using an air-brush loaded with brown-tinted lacquer, a slight remaining dark discolouration on the centre of the cabinet top was colour-blended into the surrounding wood and the entire cabinet then given one coat of brown-tinted lacquer and three coats of clear semi-gloss lacquer. The knobs were similarly treated.


 
 
   

Before restoration.
 
   

 
 

The chassis was fairly straightforward to restore - mainly cleaning, re-capping (to replace the electrolytics and paper capacitors), plus a few resistors replaced, some minor re-wiring and the bias-cells replaced with alkaline 'button-cells'. Otherwise just a general clean-up and realignment was needed.

The set took quite a bit of effort to re-assemble though - the new speaker cloth was glued onto its wire-mesh form and tacked it into the cabinet. The speaker baffle was then mounted into its 'proper' place (ie. where the screw holes on the cabinet indicated it should be), the speaker fitted, but then it found that the chassis wouldn't quite fit in the cabinet. After a lot of fiddling about, it was assessed that the speaker baffle needed to be pushed a half an inch further in towards the case (on closer examination, there were more screw holes at this location) - it eventually became apparent that the speaker fitted in this unit was a replacement (and likely belonged to another radio) and the guy that had fitted it long-ago had re-located the speaker baffle to accommodate the (larger) electro-dynamic magnet assembly and output transformer beside the chassis.

The result is a fine-looking and sounding table-top with a great-looking dial and that oh, so magical 'eye'!


The restored chassis ...
 
   

... and wiring.
 


The restored receiver.
 
   

View into the back.
 


Slide-rule dial.
 
   

The Magic Eye
tuning indicator.
 



  Marconi 142 Restoration
Projects
SPARC