A Collins 75A-4 Receiver Restoration Project
Page last updated May 18th, 2019
I acquired this 75A-4 receiver with serial number 1360 around 2006 in very good condition at the time. However it was badly damaged in 2010 when some home intruders knocked it off the shelf where it resided. There is a photo below showing it on the floor. Most of the damage occurred to the cabinet paintwork as well as the two glass dial windows and the S-meter. It sat idle for four years until 2014 when the case was removed from the radio, packed up and sent to Howard Mills, W3HM in the U.S.A. Howard specialises in radio restorations including refinishing Collins 75A-4 enclosures. The refinished cabinet panels arrived a few months later but no further progress was made on the restoration until 2019 when I developed some interest in this receiver again.
The multi-section power supply electrolytic filter capacitor has been replaced as well as all of the black 0.1uF capacitors which are used mainly for D.C. supply rail bypass purposes. I have acquired a replacement S-meter as well as a two new pieces of dial glass. A replacement dial label was also fitted to the revolving dial drum as the original was very yellowed and tired looking.
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Below images show the drum dial before and after the original overlay being replaced with a new one. The front panel is being reassembled and the eleven black 0.1uF capacitors have been replaced.
I decided to have a go at producing a new dial drum overlay for my 75A-4 receiver using Express PCB software again. The result was quite good in my opinion. I had a template to work from to make all of the measurements. The 15 metre band was different between early and later model receivers. Later models started at 20.5 MHz and earlier production models started at 20.8 MHz as I understand it.