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Success Stories If you have successfully repaired or restored a piece of equipment, why not write up what you did and post details here. Particularly if it was interesting, unusual or challenging. PLEASE DO NOT POST REQUESTS FOR HELP HERE! |
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1st Jan 2021, 1:22 pm | #1 |
Octode
Join Date: Nov 2003
Location: Bath, Somerset, UK.
Posts: 1,804
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Masteradio 500 CarRadio
Its not often that I write up my success stories here, I am too busy getting them done, but this restoration covers some of the complexities encountered when working on vintage car radios which we may expect to encounter.
The Masteradio 500 was developed just after the war and was marketed from 1946. Although primarily for car use, it was also used by small charter airlines for passenger comfort. Masteradio called upon its wartime heritage when designing this as there are some elements of its design that are common to military and aircraft radios. Employing a synchronous vibrator in the power pack, there is no need for a selenium or hollow state rectifier, however this aspect made restoration a little more complex. After opening the vibrator, both sets of contacts were burnished and polished to ensure correct primary switching and secondary rectification after re-sealing. The under chassis view showing the original chassis view shows just how crammed the layout is, necessary to make the radio as compact as possible. When recapping, I decided to use small radial leaded capacitors in order to create more space. In addition to the main chassis re-cap, the power pack capacitors were replaced (the values of these are critical to correct operation of the unit) and the main reservoir and smoothing electrolytic was restuffed in order to preserve the above chassis view (this is also borderline in the "cram it in" design. The bowden cables to the remote panel freed off after a soaking with Plus Gas and apart from a little play work quite well. The concept of a remote panel is novel but messy as it makes the set difficult to display and store. I had to fabricate a replacement speaker panel as the original was missing, luckily I had recently scrapped an old Philips set which yielded an ideal speaker that fitted the void of the chassis perfectly. Using a length of RG58 co-ax cable suitably trimmed and terminated in the original bayonet antenna connector yielded good results relatively free of vibrator noise. Considering that this set was under a pile of rubble at the back of a damp car servicing workshop for over 60 years, I think it has survived rather well. Vintage car radios are a little different with some unusual design features but are quite restorable with care, give it a go! Neil
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preserving the recent past, for the distant future. |
26th Jan 2021, 9:52 am | #2 |
Dekatron
Join Date: Feb 2009
Location: Chesterfield, Derbyshire, UK.
Posts: 3,737
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Re: Masteradio 500 CarRadio
Nice one Neil, I see some of the old car radios are fetching good money these days, I used to have one of the HMV's the one with a box with the if's and audio stages in it ,the tuner had several push buttons /tuning and on off v/c, all in a nice little box with chrome surround , I had it fitted in my Triumph 2000 ,Happy days ,Mick.
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26th Jan 2021, 1:06 pm | #3 |
Nonode
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
Posts: 2,085
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Re: Masteradio 500 CarRadio
An interesting model to preserve: it shows the use of the established techniques at the advent of new requirements, like the tuning capacitor, vibrator, and "hollow state" technology
btw, you seem to have one of my BA nut spinners there, next to my solder sucker
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27th Jan 2021, 11:23 pm | #4 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,527
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Re: Masteradio 500 CarRadio
They look suspiciously similar to mine too. I'd blame RS in the '80s for their ubiquity
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28th Jan 2021, 5:20 pm | #5 |
Octode
Join Date: Nov 2003
Location: Bath, Somerset, UK.
Posts: 1,804
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Re: Masteradio 500 CarRadio
Thanks for your replies and your interest.
Shortly after completing the restoration, I approached the owner of the Avondale Garage to ask if he had any of the screen printed brass dealer labels from the 1930s. He still had a supply of these so I fixed one to the side (visible in the final image), the phone number is "Batheaston 66". Work on the set was briefly put on hold due to a shortage of a 6BAnut spinner (necessary to remove the power pack). Luckily I bought a BA set at the car boot whilst in the midst of the restoration. I buy all of my solder suckers at the car boot, I normally only go for the RS ones nowadays as these seem to last longer. When I left work a year ago I had a brief panic as I wondered if I had left anything useful behind there but I need not have worried, what I did not bring home on my last day I was easily able to obtain at the car boot. Neil
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preserving the recent past, for the distant future. |