HMV Smiths Radiomobile 100 – Restore & Upgrade
This 1947 HMV Smiths Radiomobile 100 was restored and upgraded to modern standards with an Aurora FMR2.7 AM/FM 4 x 45W Stereo radio and an Aurora HPC-1 high power positive earth converter unit.
It lives in a beautiful 1947 Bentley MK VI. The owner wanted it to function perfectly and look lovely, but return to the car with just the same connections and no more. That meant a single power cable and an aerial socket. We did sneak in an AUX input socket, tucked away discretely at the top rear of the case, but nothing more.
All the controls function as expected and the radio even takes around 20 seconds to ‘warm up’, accompanied by the ‘vibrator buzzing’ exactly as the original did.
The first challenge with a Radiomobile 100 restoration is to build the chassis of the radio and fit all the restored controls and switches.
This includes re-stringing the dial and tuning capacitor. It’s one of the most challenging jobs in classic car radio restoration, with at least 8 hands required, but we always fit a new cable. The original is invariably frayed and will almost certainly break when it’s put back into regular use, so a replacement is essential.
Of course replacement Radiomobile 100 dial cables aren’t available off the shelf these days. We make our own up using 0.8mm 7 strand cable which has a breaking strain of 24lbs. Much stronger than the original.
This upgrade included an Aurora HPC-1 high power positive earth converter which was fitted to a custom aluminium heat sink inside the case. As this upgrade only used a single speaker this was a bit more than required, but a future owner may want to use all four speakers and demand more power from the converter, so we built the radio to cope with any possible future requirement.
The Aurora FMR-2.7 AM/FM 4 x 45W RMS stereo radio unit was also fitted on a suitable heat sink in the upper part of the radio case. Note the high quality Audison PRIMA APX4 4″ 50W speaker fitted inside the case too. Space inside the case is very tight and this speaker is tricky to fit, but it’s well worth the effort as with only one speaker this radio needs a really good one to sound great.
The Audison APX4 is fitted securely using four 2BA bolts. The original fixing bolts are too far apart and won’t fit the new speaker. It would be easy to drill new holes in the front of the case, but that would just look wrong, so we fabricate special fixings that allow us to fit the new speaker on the old bolts. It takes time and effort, but the results are worth it.
Finally, it’s essential to get the details right, and so a period correct bakelite fuse holder was fitted to complete the restoration.
The finished radio will provide entertainment for many years to come and we always enjoy returning a beautiful and fully functional radio to the owner.
This one has been fully restored and looks like new, as this was what the owner wanted. However, we also restore many of these radios with the patina of their age totally retained. They simply look like they’ve been well cared for and are totally original … on the outside!